PDA

View Full Version : TRS80 - Model 4 disk error



Lorne
January 19th, 2009, 03:14 PM
I just got what was supposed to be a working TRS80 - Model 4. It's real clean on the outside (no yellowing at all - good thing as I'm getting worn out on the de-yellowing).
It asks for a disk, I insert what is supposed to be a new boot disk, and I get "disk error".
I've searched the forums, and read a few posts, but haven't found anything that exactly matches my problem.
Is "disk error" more likely to be a problem with the disk, or a problem with the disk drive?

I opened up the TRS and found a dead spider, a web and a couple small styrofoam balls hanging off the web.
1209
Maybe that was part of the problem? Probably doesn't help, huh? I'm about to vacuum those out.

patscc
January 19th, 2009, 03:33 PM
There's two drives, right, one's just taken out for the pic, right ?
Can you tell if the drive is spinning & the head going in and out ?
You might need to clean the rails & lube them a bit if the thing has been sitting for years and hosting spiders.

patscc

tezza
January 19th, 2009, 03:37 PM
Yes, "disk error" could mean anything. The Drives, or maybe the floppies themselves.

I don't suppose you have a working Model 4 you could test the disks on? This would eliminate faulty disks anyway.

Do the usual. Clean the heads and then if that doesn't work open it up and clean the rails. It's probably little point in going any further than that until you can verify the disks themselves are ok.

Could you test the disks in an emulator which reads floppies (e.g. David Keil's)? Or did you make them using an emulator?

Tez

chuckcmagee
January 19th, 2009, 03:43 PM
I usually drag out my 5.25 inch wet cleaning diskette and the provided bottle of strong alcohol that came with it. I keep accessing the drive to keep the cleaning disk spinning, for around 1 minute most times.

I had a Kaypro II where I stuck what I knew was a good disk. I just kept doing a "dir" command over and over after the heads had had a chance to dry out from alcohol. After like 30 or more retries, it finally started working with no errors. That was on the drive A:. I tried the same trick on the bottom drive and after more than 50 retries, I gave up.

Those do look like styrofoam balls. Hope they weren't spider egg cases!! You could end up with 300 tiny spiders coming out of the vacuum.

Lorne
January 19th, 2009, 04:21 PM
There's two drives, right, one's just taken out for the pic, right ?
Can you tell if the drive is spinning & the head going in and out ?
You might need to clean the rails & lube them a bit if the thing has been sitting for years and hosting spiders.

patscc
There's two drives and they're both in place - there's just a load of room between them.
The drive spins - I only took the cover off after the "disk error". I check and see if I can see the head moving.
Last time I removed a drive to clean and lube the rails, I screwed up and it didn't work at all (that'll be my last resort).

patscc
January 19th, 2009, 04:26 PM
Lorne said...I screwed up and it didn't work at all (that'll be my last resort).
If it comes to that, make sure you take pictures as you go along. They're great to refer back to.
What is the disk you are trying to boot with, anyway ? TRS-DOS, LS-DOS, what ?
patscc

Lorne
January 19th, 2009, 04:27 PM
I don't suppose you have a working Model 4 you could test the disks on? This would eliminate faulty disks anyway.

Do the usual. Clean the heads and then if that doesn't work open it up and clean the rails. It's probably little point in going any further than that until you can verify the disks themselves are ok.

Could you test the disks in an emulator which reads floppies (e.g. David Keil's)? Or did you make them using an emulator?

Tez

I wish I had another Model 4 !
I cleaned the heads two times using a cleaning disk, and no luck.
I don't have a working emulator yet - that's something else I have to work on.
I bought the boot disk off an EBay company that provides operating system disks for TRS-80's.

I'm thinking maybe I switch the phyical A disk with the B disk, as maybe the B has had less use, and then I can test it with the operating system disk, and see if it will boot with that disk drive.
That could tell me that either both disk drives are no good, or the boot disk is no good.

Lorne
January 19th, 2009, 04:28 PM
[QUOTE=chuckcmagee;85096]
I had a Kaypro II where I stuck what I knew was a good disk. I just kept doing a "dir" command over and over after the heads had had a chance to dry out from alcohol. After like 30 or more retries, it finally started working with no errors. That was on the drive A:. I tried the same trick on the bottom drive and after more than 50 retries, I gave up.
QUOTE]

Tried two times, for about 45 seconds each time.
Maybe a couple more goes, will do the trick.

patscc
January 19th, 2009, 04:29 PM
Do you have a DOS or Windows box with a 5.25 drive ?
patscc

tezza
January 19th, 2009, 04:30 PM
Have you tried switching the drives around?

That might help ascertain if it's a drive problem. You'll probably need to reset jumpers if you do this, and move the terminator.

First thing is a head clean of course. I would clean both drives. If that doesn't work, try swapping them. If the disk doesn't boot on the swapped drive, suspect the disk of being faulty.

There is a small chance BOTH drives are non-working of course, especially if they have been neglected.

Tez

Lorne
January 19th, 2009, 04:31 PM
If it comes to that, make sure you take pictures as you go along. They're great to refer back to.
What is the disk you are trying to boot with, anyway ? TRS-DOS, LS-DOS, what ?
patscc

I'm using a disk labelled TRSDOS/LS-DOS 6.3.1 J

I've also just ordered a bunch of different operating system disks from: http://www.trs-80.com/. Maybe one of those will work better.

Lorne
January 19th, 2009, 04:38 PM
@patscc
The only other 5.25" machine I have is an Altos 5/15 running CP/M.

@TEZZA
Can't I just disconnect and remove the drive, out it in the other location, and then reconnect the wires, or is there something on the drive that tells it that it's an A or a B?

I can olny clean the A drive. Until I get the A working, I can't do a DIR on B, and B won't do anything when I insert a disk.


I'm off to try a couple more cleanings, and see if I can see the heads moving.

chuckcmagee
January 19th, 2009, 04:40 PM
As Tez noted, there are jumpers set on the A and B drive. The drives don't actually have to be moved, just the jumpers redone. This can get very tricky, depending on how cheap they were. Most of the time, they just cut the connection between the 2 sides or pull one pin out of the socket so it sticks out at a 90 degree angle. Do that a few times and the jumper leg fatigues and falls on the floor. Better drives have a dip switch block which is much easier to change.

chuckcmagee
January 19th, 2009, 04:47 PM
Ok, looking at some of my floppy drives. The jumpers are usually close to the edge connector. I have one that is configured as drive B and it has ONLY one signal joined together. If you count FROM THE RIGHT OF THE DIP BLOCK, it is the 3rd one. If you connect THE SECOND ONE and not the 3rd one, it will be Drive A. I keep reading that ALL the other signals are not required on drives that have a mechanical head loading mech. like I am sure yours does.

chuckcmagee
January 19th, 2009, 04:50 PM
And finally, it does NOT matter where drive A and drive B are on the cable. So, it is usually the easiest to change the jumpers, put everything back like it was originally, and it will attempt to boot off the bottom drive, not the top one.

Lorne
January 19th, 2009, 04:51 PM
@TEZZA
My mistake - the B drive spins when I put the disk in - I game it and the A a couple cleanings.
I didn't see any heads moving - there's room between them but not enough to get a good view. I'll need a little dentist mirror.

@Chuckcmagee
I'll look for those pins.

Thanks guys.

tezza
January 19th, 2009, 05:00 PM
If you can ascertain who made the drives (Tandon, TEAC, etc) you can sometimes find info on the web as to where these jumpers should be.

However, they are usually easy to spot. Look for pins and jumpers labelled 0,1,2,3 or 1,2,3,4. Trouble is every drive manufacturer put them in a different place and often used a different method of switching them. Look at the circuit board on both drives. The boot drive will have a jumper or connector set to the lowest number (either 0 or 1). The second drive will be the next highest number up.

Tez

Lorne
January 19th, 2009, 05:14 PM
OK, here's a couple pics of the boards mounted to the drive B.
I'm not sure what I'm looking for.
1211
1212
Just got back from taking these, and saw Tezza's reply.
The drive is manufacturered by Texas Peripherals.
This is a photo of the model number? of the board attached to the drive.
1213

patscc
January 19th, 2009, 05:20 PM
If you have the drive out( and unpowered ), see if the head assembly moves in and out reasonably easily by hand. Since it's a stepper motor, you'll feel a very slight 'stepping', almost small indents. This is ok. If the head sticks, or is hard to move, then it's time to clean & lube the rails.

You should try to get your hands on a 5.25 for a modern machine as you can often download/borrow boot disk images from various folks.

The problem is you've no way of ascertaining the quality of the boot disk, although I think it's the drive that's going to need a bit of work.

Do the rails & band, or whatever connect the stepper to the head, look like they've old, stale grease, or grease & dust on them ?

As always, pictures are welcome.

patscc

chuckcmagee
January 19th, 2009, 05:20 PM
Ok, right next to the edge connector, see how there is an open slot in the edge connector. Now look directly toward the front of the drive, right next to that open slot. See the solder blobs with 1, 2, 3, 4 printed next to them. Each one has a trace that goes to another blob in the same position.

It looks like THE CABLE DOES DETERMINE THE DRIVE ORDER!!

All the traces are connected! Which means the drive doesn't select which drive it is.

Lorne
January 19th, 2009, 05:24 PM
It looks like THE CABLE DOES DETERMINE THE DRIVE ORDER!!

All the traces are connected! Which means the drive doesn't select which drive it is.

So, I'm good to just switch the physical drives (or the cables), and see if it boots then, right?

(If so, and it boots from that drive, then I'll do the proper cleaning on what was the A drive).

chuckcmagee
January 19th, 2009, 05:27 PM
Yes, I could NOT find anything in the picture that selects which drive it is. On new PCs, they have a half twist in the floppy cable so that one ends up as A and the other ends up as B even tho each drive is configured as B.

So, yes, just move the cable connections or the drives and try some more.

Lorne
January 19th, 2009, 05:44 PM
OK, I switched the physical locations of the drives.
There must be something on one of those boards somewhere.
I turned it on, an instead of asking for "diskette?", it displayed "cass?" (for cassette, I assume), I hit enter and it displayed "size?".
I think it wants a cassette, seeing as it can't find A where it thinks A should be.

Any other way to fool this thing into thinking B is A?

patscc
January 19th, 2009, 05:52 PM
Take a look at the connectors on the drive cable. Does it look like some of the contacts have been pulled ? Some Tandy's handled drive select that way, although I can't remenber if the 4's did or not.
The drives are both the same, right ?
patscc

tezza
January 19th, 2009, 05:53 PM
Hmm...

Lorne, is there any way you can supply a large picture of the top circuit board. Attach it as a file perhaps? That way we can have a good look at the board.

Tez

tezza
January 19th, 2009, 05:55 PM
check there is not a dip swtch under the circuit board opposite those soldered connectors chuckcmagee noted.

Tez

chuckcmagee
January 19th, 2009, 05:56 PM
I sure can't see any drive select on the one picture you did. Those blobs with the short traces are for the drive select (the ones numbered 4 3 2 1). And none of the traces are cut. Normally only one would be connected, not all 4.

So, checking over the connector is a good idea, where they pull out some of the connection metal so it will NOT make a connection. Achives the same effect of blocking the signal.

Lorne
January 19th, 2009, 05:59 PM
The drives look exactly the same to me.
I'll inspect some more, and take some pics of the top of the board.
I can't attach them as a decent image, as the file size will be too large.
Let me see if I can take a couple, and if they aren't big enough, I'll send Tezza an email with a larger file. If Chuckcmagee would PM me your email address I can send it to you too.
Thanks.

chuckcmagee
January 19th, 2009, 06:00 PM
Nope Tez. If there was a normal "dip switch" soldered in that position, the traces would be gone. The dip switch would provide the path for the signal, not the trace.

chuckcmagee
January 19th, 2009, 06:02 PM
my email is chuckcmagee at msn dot com. Yes yes, replace the at with @ and dot with . We do that so stupid bots can't harvest them.

tezza
January 19th, 2009, 06:05 PM
Nope Tez. If there was a normal "dip switch" soldered in that position, the traces would be gone. The dip switch would provide the path for the signal, not the trace.

Fair enough. It's weird then. I've also looked (squinted) over that picture and it does seem those solder points and links are the drive select area. I can just make out 1,2,3,4. Strange that they are all connected?

Perhaps the Model 4 behaves differently to earlier TRS-80s and there is another way of drive selection? Is there a twist in a part of the cable Lorne? Similar to the old 5.25inch connections on older PCs?

Any Model IV owners reading this who know how the drives are selected?

Tez

patscc
January 19th, 2009, 06:06 PM
Lorne, if you want, cc me on the pics as well. You should still have my email address somewhere.
patscc

Lorne
January 19th, 2009, 06:14 PM
Here's 3 pics - best I can do at the moment.
1214
1216
I've emailed Chuck for higher res images.
Tez: I have your physical address, but not your email address, and I can't wait three weeks for the post !

tezza
January 19th, 2009, 06:18 PM
Email is terry-at-webweavers.co.nz (replace the -at- with @).

Yup, they do look like the drive selectors. And they appear to be all linked??

Tez

Lorne
January 19th, 2009, 06:27 PM
Take a look at the connectors on the drive cable. Does it look like some of the contacts have been pulled ? Some Tandy's handled drive select that way, although I can't remenber if the 4's did or not.
The drives are both the same, right ?
patscc

I just checked the large grey ribbon connectors on the drives.
The B drive has no connector in pin position 5, which would be the #4 (of the 1,2,3,4) on the board. The A drive does have a connector in that position.
So maybe I hookup the B drive to A's ribbon connector?

Lorne
January 19th, 2009, 06:33 PM
So maybe I hookup the B drive to A's ribbon connector?

OK, so that din't work.
I hooked up what was the physical B drive to the A drive's ribbon cable, and it's looking for the "cass?" again.
This is weird.

patscc
January 19th, 2009, 06:33 PM
The drive select would then be driven by the cable.
Swapping drives should work, but you might have to move the termination pack.
On one of your pics, near the connector, there's something called 'R51'. Is that just a socket, or a black lumpy single inline part with 8 or 9 pins ?
But I'd try it without swapping term packs first, maybe you'll get lucky.

patscc

chuckcmagee
January 19th, 2009, 06:33 PM
Ok, it has to be something in the drive cable. Like the pulled connector theory. Also, do the " pencil eraser " trick to clean some of the oxide of that one darker one. Don't erase real hard or for long periods of time. Just trying to get to the shiny metal again. I used too much force once and actually erased the traces altogether (on one of those super cheap ribbon cables where the connector is "painted" on).

You can also try just hooking up one drive at a time, using the same location on the cable for each drive (one at a time).

I have to go clean up my dog. He has poop all stuck in his fur.

Chuck(G)
January 19th, 2009, 06:37 PM
I know that Texas Peripherals was a joint venture between Tandy and Dataproducts, but man, do these drives look like Tandons! I wonder if they are Tandon mechanicals with TPI's electronics board.

At any rate, the furthest drive from the CPU on the cable should have a terminating resistor installed; the near one should not. Looking at the drive photos, I'll guess that the terminator is that SIP package near the connector, though I can't be sure. At any rate, only one drive should have the pack installed.

Cable problems on the TRS-80s were legend. Pull the cable off the CPU side and clean all contacts and then give it a try.

Lorne
January 19th, 2009, 06:44 PM
OK guys - thanks alot :)
(With all your tips, I'll be up for another three hours !)
I'll post results tomorrow.
Thanks again.
Lorne.

chuckcmagee
January 19th, 2009, 06:52 PM
Yes, it is a SIP resistor pack. Only one installed on the B drive.

The missing connector (#5) would be the Drive A select signal. So, the one with the missing connector 5 is the B cable.

That SIP pack pulls straight up out of the connector. Should be easy to move back and forth if careful to not bend the pins while removing it.

Terry Yager
January 19th, 2009, 08:01 PM
So much helpful advice, but apparently not much experience with TRS-80s here.<where's that damn smiley button...???>

Yes, the drives (in most Trash-80s) are 'selected' by removing pins from the cable connectors (or never installing them actually), and yes, simply swapping the drives around should work. Why is there a large space between the drives? Are the drives half-height? If the drives have been swapped out from another kind of machine, you may need to do some extra work with the drive selects (can't recall exactly, I'll try and check my sources), unless it's been done already by a prior owner. Or, perhaps the cable is not the original one. Are both connectors missing pins, and are they different pins? Texas Peripherals supplied RS with many (all?) of their drives, so that sounds kosher. They are pretty much Tandon clones.

If everything is connected and working, the bottom drive is :0 (the boot drive), and the top one is :1.

When it's prompting for Cass?, is the disk in the drive? Either way, just hitting 'return' a couple times at that point should boot it into BASIC. Does it work that much?

Report back, and we'll take it from there.

--T

Druid6900
January 19th, 2009, 08:20 PM
Actually, that's not entirely true, T.

The TPI drives were the only ones used in the Model 4 that did NOT have jumpers on the board (I know, I have several of them here). All other drives were dipshunt selected.

Drive 0 would have pin 10 removed from the connector, 1 would have pin 12 removed, 2 would have pin 14 removed and 3 would have pin 32 removed (2 and 3 would, of course, be external). It's the same setup as the Model I drives. Any TPI drive should work in any position, just as it is.

The Cass? Prompt would show up when the system didn't detect any drives in the unit (or when you turned the unit on while holding down the break key).

The drive speed is also important and check the strobe disk under a flourescent lamp which adjusting the speed control (usually a long blue object on the PCB with a little slot screw on the end)

Terry Yager
January 19th, 2009, 08:31 PM
Actually, that's not entirely true, T.

I was wondering where you were, D. Glad ya finally chimed in. I can't recall if I've ever seen any other than the TP drives in a Mod I/III/IV, but you've seen a whole lot more of 'em than I have.

--T

Druid6900
January 19th, 2009, 08:42 PM
Basically, the Model I used (OEM) Shugart 400s and Tandon 35 track drives (don't recall the model off the top of my head).

The Model IIIs used the same Tandons and the very last of them used TPIs as did the Model 4s (until they used up their stock of Tandons) except for the 4D which used some really weird 40 track DS drives which I have one of but can't recall the make or model right now)

A lot of people changed the stock drives though and, in the IIIs and 4s, you could use 2 DS drives (35 or 40 track, depending on the operating system) as your 4 single sided drives. You could even pull this off with the Model I with the right OpSys.

Lorne
January 19th, 2009, 08:59 PM
Jeeze, I step away for two hours to do the stuff from the last list, I come back and there's another batch of stuff to check :)

OK, first stuff first:

Here's a photo of the FDD ribbon connectors:
The one on the bottom is the A (or drive 0), and the one on the top is the B (or drive 1).
1221

@patscc
"there's something called 'R51'. Is that just a socket, or a black lumpy single inline part with 8 or 9 pins?"
It's a black inline part with 6 pins. I don't know if it's a push-on, pull-off thing or not. There's 6 wires soldered below it. There's one on each of the FDD boards.

Here's a photo of both boards, side by side. B on the left, A on the right.
1220

@chuckcmagee
I cleaned up those connections with a pencil eraser. That is a very neat trick.

@Chuck(G)
Not sure what a SIP package is. If it's the thing patscc calls a "black lumpy single inline part" , then there's one on each of the boards.

I dug into the CPU area.
I found some more things with 4 pins and numbered from 1 to 4.
One of them has four wires and the other has only three.
Only one of them was connected.
Here's some photos:
Both boards:
1219
Left side closeup:
1217
Right side closeup:
1218

Now after doing all these other tests, and putting the FDD back in, I only get "cass?" on the screen. I think that happened right after the neat little pencil eraser trick, but I don't remember anynmore. The connections all look good.

@Druid6900
From what you said, I'm not detecting any drives now.
I think the drives are original, and full height. They've got all kinds of factory stickers on them (now almost falling off), where the techs tested them and then initialed the sticker. The drives are almost 3 1/2" (89 mm) high.

@Terry Yager
When it prompts for "cass?", the disk can be in the drive or not, it doesn't even look for a disk at that point. If I hit return after "cass?", it displays "memory size?".
It doesn't boot into Basic or anything.
The farthest I got was "disk error" on the A drive, when I tried to get it to boot up. That's what started the whole thread.


Thanks guys.
I'll get back to this tomorrow.

Druid6900
January 19th, 2009, 09:08 PM
The board on the left is the Floppy Drive Controller and, if that connector isn't attached, it's getting no power (which could explain the Cass? prompt)

The board on the right is the RS-232 board.

If you hit enter at the Cass? Prompt, and then at the Memory Size? Prompt, you will go into Basic in ROM

tezza
January 19th, 2009, 09:22 PM
Those drive connectors have a few pins missing in each one, and one is different from the other. So that's how the drives are selected in these Model IVs yes?

You learn something new everyday!

Tez

chuckcmagee
January 19th, 2009, 09:30 PM
Well, we are getting there. Obviously, a power connector got accidently pulled off the main floppy control card, likely early in the process. Does explain the Cass prompt. It also means that most of the drive moving around had no meaning as the main controller card was powered off.

And yes, bottom connector has pin for drive select 1 and the others are missing. Top connector has pin for drive select 2 and the others are missing.

So, plug the power back in and move drives or connectors and see what we get out of the "new" drive 0 (A).

Terry Yager
January 19th, 2009, 09:33 PM
Those drive connectors have a few pins missing in each one, and one is different from the other. So that's how the drives are selected in these Model IVs yes?

You learn something new everyday!

Tez

That's what was confusing you about all 4 DS traces being intact. The missing pins correspond to the unused select lines, rather than cutting the traces on the board.

--T

Lorne
January 20th, 2009, 04:53 AM
@Druid6900
"If you hit enter at the Cass? Prompt, and then at the Memory Size? Prompt, you will go into Basic in ROM"

You are correct. At the "cass?" prompt, I hit enter and get "memory size?", hit enter again and it boots into "Model III Basic".

@chuckcmagee
So, plug the power back in and move drives or connectors and see what we get out of the "new" drive 0 (A).

OK, I connected the disconnected part back onto the floppy drive controller.
I put the drives back in their original positions (A in A's slot and B in B's slot). I started it up and I'm back where I was before: "disk error", which is better than "cass?"

I then reversed the drives, connecting what was physical drive B to A's FDD ribbon connector, and A to B's connector (and made sure the floppy drive controller connector was still attached).
Started it up again, and got the "cass?" message.

Put it back to original, and I get the "disk error" message.

There's got to be something else that decides which drive is in which position.
Ideas?

I don't have to switch the power connectors to the FDDs as well do I?

Thanks.

chuckcmagee
January 20th, 2009, 04:56 AM
No, you don't have to move the power cables! Power all comes ultimately from the exact same point in the power supply so which one is plugged into what doesn't matter at all.

chuckcmagee
January 20th, 2009, 05:04 AM
It is was me, I would disconnect drive B altogether. I would then try and position drive A in such a way that I could see the head mech. under the top controller board while everything was powered on and attempting to access the drive. As you found out, you really need to be able to see under that top controller board.

At that point, you can do several things. One is you can physically push the head mech. towards the front of the drive when it is off. Then, when accessed, it should move the head all the way back towards the back of the drive (track 0).

chuckcmagee
January 20th, 2009, 05:09 AM
I suppose there is a small possibility that the drive B power connector has a loose wire somewhere, so switching them around would be a good plan at some point. It does sound like either drive B isn't getting all the proper power or the controller board on drive B has some other problem. The power cable provides +5 and +12 volts.

patscc
January 20th, 2009, 05:11 AM
Lorne, have you tried moving the head asssembly in and out a few times by hand to feel how freely the assembly moves ? It the rails are sticky wih old grease, that's going to cause trouble.

Can you take a picture of the top mechanicals of the drive, so I can see what head transport looks like ?
Also, when you have a drive out, does the spindle (what the belt on the bottom does to) move freely ?

You have, I believe, a multimeter, and a logic probe on order. Has the probe arrived yet ?


Chuck(G) said...SIP
patscc said...black lumpy single inline part with 8 or 9 pins

I probably should have said black lumpy single inline part with 8 or 9 pins( SIP )

patscc

chuckcmagee
January 20th, 2009, 05:29 AM
It is pretty clear that if the computer doesn't see a drive A connected, it gives up looking at that point and defaults to the cassette interface. So, you hook up drive B in the A place, computer doesn't see the drive for some as yet unknown reason and acts like there are no drives at all.

Lorne
January 20th, 2009, 05:31 AM
OK thanks guys - have to go out for a couple hours.
I'll try taking photos of, and moving the heads when I get back.

I have rec'd the logic probe (I have no idea how to use it, but I've got it).

Meanwhile, in response to Druid6900's suggestion about timing, I've attached a photo of the top and bottom of the FDD.

1223

1224

Is this the thing (white screw thing in the center of the blue square) that I turn to change the timing? It's on the FDD board.

1226

Thanks.

patscc
January 20th, 2009, 09:30 AM
If you take a multimeter and measure the resistance between all the DS pins (the solder dots with the straight traces running to another row of solder dots) it will tell you if they're all connected together ( which means drive select is done only with the cable )
I'm looking at an old Tandon single-sided drive that looks a lot like yours, except the motor control is mounted on the bottom of the drive.

Looking at your pic of the connectors, the top one is wired as 'Drive 0', the bottom connector is wired as 'Drive 1'

The other missing pins are ( from left to right ) head select, which, since you have a single-head drive... and motor select for Drive 1, not used.

You might want to try this:
With only the 'dead' drive hooked up, jumper between the solder dots that connect to pins 12 & 14 on the connector and see if the drive is recognized. It shouldn't make a difference, not if the drive is wired correctly, but it doesn't hurt to try.

patscc

Chuck(G)
January 20th, 2009, 09:41 AM
I don't think that's the timing pot--more likely part of the read/write circuitry. I suspect that the tach pot is the 10-turn long blue one near the bottom of your first photo. At least it's on the side nearest the TO-220 power transistor that should be driving the spindle motor.

For those of you with a Tandon TM-100 handy:

Take a look at the photo of the bottom of the drive and compare it to your TM-100. Is that not a Tandon drive?

Terry Yager
January 20th, 2009, 10:00 AM
For those of you with a Tandon TM-100 handy:

Take a look at the photo of the bottom of the drive and compare it to your TM-100. Is that not a Tandon drive?

They look very similar, but the Texas Peripherals sticker is pretty much a dead giveaway.

--T

Chuck(G)
January 20th, 2009, 10:09 AM
They look very similar, but the Texas Peripherals sticker is pretty much a dead giveaway.

I suspect that Jugi Tandon sold them drive bodies sans PCBs. Even that TPI sticker looks like it was printed at the Tandon plant.

It would not surprise me one bit if parts could be interchanged between TM-100s and these TPIs.

chuckcmagee
January 20th, 2009, 10:13 AM
I was thinking the long blue rectangular pot myself, for speed control.

patscc
January 20th, 2009, 10:16 AM
The old Tandon single-sided I'm looking at (no lable) looks a lot like Lorne's, it's almost eerie.
I betcha his TO-220 transistor is a Motorola TIP110, and the speed precision trimmer is a 1 kOhm.

Didn't Texas peripherals end up getting absorbed by Tandon, who then ended up under Seagate ?

patscc

Lorne
January 20th, 2009, 10:45 AM
I haven't read all the latest replies, but I have these photos to post:

I pulled the little plastic pins out of the front of the FDD boards, slipped the boards back, and took these photos of the inside of the drives.

Drive A:

1230

Drive B:

1229


I tried moving the black pastic thing noted in the drawing above and it needed a real good push, and is stiff when moving. I've slid these on other drives and they slide nicely. This one doesn't. I tried the same thing on the A drive and it was even stiffer.
I think these may need a lube job.
It's the shiny rails I lube correct? (this is where I secrwed up another drive - lubing too much stuff).
I was using sewing machine oil and a Q-tip.
Is that the correct kind of oil?
If I get these lubed, maybe that will get rid of the disk error.

Thanks.

Lorne
January 20th, 2009, 10:53 AM
If you take a multimeter and measure the resistance between all the DS pins (the solder dots with the straight traces running to another row of solder dots) it will tell you if they're all connected together ( which means drive select is done only with the cable )

patscc

I checked, and not only is dot 1 connected to the other end of dot 1, (and so on, for 2, 3 & 4), but 1 is connected to 2, 3 & 4, and so on, and so on.....
I can try the pin jumpering in a bit.
I am going to wait and see if lubing the rails helps (once I hear that my lube is OK to use).

Terry Yager
January 20th, 2009, 10:56 AM
I was using sewing machine oil and a Q-tip.
Is that the correct kind of oil?
If I get these lubed, maybe that will get rid of the disk error.

Thanks.

Silicone grease is better, if you have any on hand. Otherwise, my next choice would be vasilene, or perhaps white lith?

--T

patscc
January 20th, 2009, 10:57 AM
I usually put some degreaser on a Q-tip (I'm assuming you don't want to mess with pulling the rails), and first clean old gunk from the rails.
Then a light oil, just a bit, use a q-tip, move head back and forth, repeat. Or you can try a wax-based lubricant, they don't trap dust & grit as much. I just recently started using those. But sewing machine oil should work.

The head assembly will feel a bit stiffer due to that particular stepper. I'm trying to figure out if the stepper spindle should have a drop of oil applied or not. Anyone ?

The disk error, possibly. The other drive not getting recognized, probably not.

patscc

tezza
January 20th, 2009, 11:01 AM
I tried moving the black pastic thing noted in the drawing above and it needed a real good push, and is stiff when moving. I've slid these on other drives and they slide nicely. This one doesn't. I tried the same thing on the A drive and it was even stiffer.
I think these may need a lube job.
It's the shiny rails I lube correct? (this is where I secrwed up another drive - lubing too much stuff).
I was using sewing machine oil and a Q-tip.
Is that the correct kind of oil?
If I get these lubed, maybe that will get rid of the disk error.

Thanks.

Yes, it would be a very good place to start. Two non-working drives I had started working after I cleaned the rails.

Make sure you get rid of all black, sticky deposits both on top and underneath the rail. Then add a very SMALL amount of light oil. I applied mine with a cotton bud (which I think is the same as a Q-tip in your language).

Then move the head assembly back and forwards until it runs smoothly. You will still feel a bit of resistance due to the stepper motor but it shouldn't be too hard to move.

Some folks recommend something like graphite instead of oil. To my mind, oil should be ok so long as it's light oil and it's applied sparingly (Also, I didn't have have any graphite at the time).

There is still a chance the disk is damaged and it would be good if that could be checked out somehow. Do you have another drive you could hook up to the unit? It doesn't even need to be full height so long as it's the right track number. A 40-track 360k 5.25 inch drive from an old PC should do I think? I'm not sure how you would alter the switches to configure the drive for drive 0 though so it's compatible with the cable. Find where the switches/jumpers are and close them all I guess?

If the repacement disk boots it will at least show the fault is with the drive and nothing else.

(Edit: I see you are getting some good advice. Ok, I'd better get off these forums for today and go and earn a living (: )

Tez

Terry Yager
January 20th, 2009, 11:01 AM
Whatever lube you do use, less is more.

--T

chuckcmagee
January 20th, 2009, 11:03 AM
Ok, get somewhat complicated at this point. I have a floppy drive sitting right here, next to me. It has the same kind of stepper motor as your drives. The stepper motor OBVIOUSLY has permanent strong magnets in it, to help with the proper step size. When I move the head on a known working drive, it is fairly hard to move the head and you can feel the magnets resisting the movement in a studdering kind of motion.

So, when they work, they are somewhat hard to move in the first place.

Yes, light oil is an excellent choice.

What I did was hook up the drive with the controller board not fastened down. I moved it towards the back of the drive and canted it up against a non-conducting part of the drive. I then moved the head all the way towards the center post, powered machine on and watched the drive access arm working. If it moves in a jerky fashion or doesn't move at all, that is the problem with the drive.

Lorne
January 20th, 2009, 11:10 AM
It is was me, I would disconnect drive B altogether. I would then try and position drive A in such a way that I could see the head mech. under the top controller board while everything was powered on and attempting to access the drive. As you found out, you really need to be able to see under that top controller board.

At that point, you can do several things. One is you can physically push the head mech. towards the front of the drive when it is off. Then, when accessed, it should move the head all the way back towards the back of the drive (track 0).

With both drives now out, I put drive A back in and connected the power & ribbon cables (no drive B hooked up).
Turn on the power and it gives the Cass? message. Seems it wants both drives hooked up all the time.

With the power on, I looked underneath and the the spindle and pulley things spin freely.

Lifted the board off the top, turned the power on and the heads (if that's the black plastic thing), doesn't move forward or back. It kind of jumps though, like it wants to go somewhere but it's stuck. There's a clicking sound that goes along with it trying to move. I don't know if those rails were ever lubed - they feel dry as a bone, and not slippery.

chuckcmagee
January 20th, 2009, 11:13 AM
Ok, the results are IN. Sure sounds like remove gunk, lube, move around a bunch, etc. time.

Just before that, move the head all the way to the center and see if it returns to track 0 when power is back on. If it just sits there and clicks, then it is for sure gummed up.

chuckcmagee
January 20th, 2009, 11:25 AM
Remember the R51/SIP thing? Appears to me that there IS one installed on the B drive and NOT INSTALLED on the A drive. People here are always saying those " termination resistor packs " thingies. Here is a pretty clear case where if the electronics doesn't " see " the termination pack, it doesn't see a drive at all.

Lorne
January 20th, 2009, 11:34 AM
Just lubed the drive A rails (only had sewing machine oil around).
They moved better than before lubing, but still some clicking resistance.
Hooked up just the A drive again.
Turned on the power.

Got a "Cass?" message (heads were positioned at the inside of the drive = middle of a disk), and heard a clicking sound as the motor tried to move the heads.

Pushed heads to what would be the outside of a disk, turned the power back on, and got a "Diskette?" message, with no clicking of the drive. Inserted a disk (now couldn't see the heads moving, but suspect they were not, as there was no clicking), and I got a "disk error" message.

This ones a riot !

Now, where did I put that damn sledge hammer?

Lorne
January 20th, 2009, 11:39 AM
Remember the R51/SIP thing? Appears to me that there IS one installed on the B drive and NOT INSTALLED on the A drive. People here are always saying those " termination resistor packs " thingies. Here is a pretty clear case where if the electronics doesn't " see " the termination pack, it doesn't see a drive at all.

Is this what we're saying is the thingie?
1231
There's one of these on both drives !

patscc
January 20th, 2009, 11:44 AM
Lorne, could you post a link to the logic probe you bought ? I want to look at the capabilities of it. My next suggestion was going to check the drive lines for the stepper to see if the stepper is being pulsed properly, or if perhaps the drive circuit is toast, but I figure I better look at your tools first before I throw out undoable suggestions.

Anyone, would a few drops of oil against the drive shaft of the stepper do more harm than good ?

Lorne, the drive doesn't seem to have a lot of corrosion, correct ?

patscc

Lorne
January 20th, 2009, 11:44 AM
Just realized I've got a full height drive from an Osborne 1a parts machine I could try, but it doesn't have a "termination resistor pack thingie" on it.

The rails on that one Osborne drive (Micro peripherals Inc) move much easier than the one I just lubed.

And I've just been lubing the rails - I haven't taken the heads off the rails. I guess that might make it slide a bit easier no?
But is that a dangerous job? (removing the heads from the rails)

Lorne
January 20th, 2009, 11:48 AM
Lorne, could you post a link to the logic probe you bought ? I want to look at the capabilities of it. My next suggestion was going to check the drive lines for the stepper to see if the stepper is being pulsed properly, or if perhaps the drive circuit is toast, but I figure I better look at your tools first before I throw out undoable suggestions.

Anyone, would a few drops of oil against the drive shaft of the stepper do more harm than good ?

Lorne, the drive doesn't seem to have a lot of corrosion, correct ?

patscc

C-S Sales - search for "Digital Logic Probe with Beeper # LP-560"

The drive doesn't appear to have any corrosion at all, or any gunk to clean up off the rails. It looks real clean.

chuckcmagee
January 20th, 2009, 11:49 AM
The one on the A drive seemed to me to just be the connections available for the SIP to plug into. While the B drive actually had one installed.

Am I misinterpreting those hires pictures? It really looks like the one drive just has the connectors and not the resistor pack.

When you moved it to track 0, there is a very small microswitch that gets pressed in by a plastic piece. This lets the drive know that it has indeed moved all the way "in" to track 0.

chuckcmagee
January 20th, 2009, 11:53 AM
Just sliding the heads back and forth on the rails should be good enough.

Don't think I would lube the stepper motor part at all.

Lohmeyer
January 20th, 2009, 12:02 PM
Did you ever confirm if the floppy boot disk you have is good or bad? Unfortunately, you might have ruined the floppy the first time you used it, so confirmation really means seeing a disk work in one machine, and then trying it in yours. Of course, I know you can't do that because you don't have another machine, but I can't stress enough the importance of knowing that your boot floppy is good before you try anything else like disassembling a machine.

I tried to read through this entire thread, but I may have missed some details. Sorry if my comments are out of sync.

The question you have to ask is did the machine not boot because of a) a bad floppy disk, b) a bad floppy disk drive or controller electronics, or c) because the disk drive head/rails, etc. needs cleaning and lubrication.

My point is, you have touched, manipulated, and disconnected many things now, and possibly caused additional problems without confirming the most simple thing - is the floppy disk OK. Just trying to keep some perspective because I have made the same mistake - even when I should have known better.

Lorne
January 20th, 2009, 12:02 PM
The one on the A drive seemed to me to just be the connections available for the SIP to plug into. While the B drive actually had one installed.

Am I misinterpreting those hires pictures? It really looks like the one drive just has the connectors and not the resistor pack.



Here's a new pic of A:

1232

And one of B:

1233

Am I supposed to be looking at something else - is it the long black thing near the ribbon connector?

Lorne
January 20th, 2009, 12:07 PM
Did you ever confirm if the floppy boot disk you have is good or bad?

Unfortunately no - it was a new disk purchased online from a company that makes boot disks for the TRS's.
I haven't got a replacement from another source yet - that could be a few days. I suppose I could stick the disk in an Osborne, and make sure there's even a file or two on it.

In any case, the disk drive heads (for A) should be moving, and they are not.
I was trying to use the B drive as it has probably had less wear, but we haven't been able to figure out how to fool the TRS into acepting the physical B drive as an A drive.

patscc
January 20th, 2009, 12:08 PM
The socket is correct, but you should have the SIP that actually plugs into it on one them.
So it looks like you don't have a termination pack SIP ?
Although that'll cause problems, I'm not convinced that it'll completely screw up the boot.
Lohmeyer's suggestion has merit, at this point it might be worth while waiting for a known good boot disk.
Unless, of course, the eBay boot disk is warranted...
patscc

chuckcmagee
January 20th, 2009, 12:08 PM
Hey, they both look the same! Really looks like just connectors to me! Not sure if there are resistors in there or not. Time for someone else's knowledge.

Lorne
January 20th, 2009, 12:12 PM
I suppose I could stick the disk in an Osborne, and make sure there's even a file or two on it.


Well, that doesn't work - the Osborne "can't recognise diskette in drive B"
Differeent formatting for Osborne vs TRS-80 ?

chuckcmagee
January 20th, 2009, 12:15 PM
Well, on drive A, when you moved the head manually to track 0 (all the way towards the back of the drive) you got a "diskette" prompt instead of "cass". Could try the same thing with the B drive. Manually move the head all the way to track 0 and try it in the A position.

You can also watch how the microswitch works. On my drives, there is a block of plastic with a slope on the front. As the head moves backwards towards track 0, it slides over the tiny switch and pushes it in. Microswitches have a distinctive "click click" as you push the little tab in and release it.

So, maybe you will get some action out of B in the A position with the heads at track 0.

patscc
January 20th, 2009, 12:17 PM
Lorne, is your stepper motor (the one attached to the head assembly) a KP4M4-001, by any chance ?
patscc

chuckcmagee
January 20th, 2009, 12:24 PM
And, Lorne, I am only about 2 weeks ahead of you. I went thru all of this same stuff trying to get 3 Shugart drives to work. Eventually, it became clear that the electronic control boards on all 3 were defective. The stepper motor mech. on the Shugarts is a much worse design than the later stepper motors. It's a hard rubber circle with a groove cut into it. The head has a little metal piece that rests in this groove and thereby, moves the heads. Really poor design!

Lorne
January 20th, 2009, 12:33 PM
Well, on drive A, when you moved the head manually to track 0 (all the way towards the back of the drive) you got a "diskette" prompt instead of "cass". Could try the same thing with the B drive. Manually move the head all the way to track 0 and try it in the A position.

So, maybe you will get some action out of B in the A position with the heads at track 0.

Yep - I see the microswitch - I'll try B in there with the heads back at the microswitch and see if I get cass? again.

On the same note - is this anything special?

1234
1235

These two photos are of the underside of the FDD boards under the ribbon connectors. One has a lump of solder on the edge of it (joining some pins?), while the other has no solder, but has green stuff.
If that's something, maybe I just take the board off B and switch it with A's board?

Lorne
January 20th, 2009, 12:34 PM
Lorne, is your stepper motor (the one attached to the head assembly) a KP4M4-001, by any chance ?
patscc

My stepper motor is a:
Type 17PS-C007-10
TPI P/No. 47-0002-01 Rev B

Terry Yager
January 20th, 2009, 12:36 PM
Well, that doesn't work - the Osborne "can't recognise diskette in drive B"
Differeent formatting for Osborne vs TRS-80 ?

Yes, very different. The Osborne won't see anything on the TRS-80 disk, or vice-versa. Physically swapping out the drives is also not going to work, as the O1 drives are even stranger than the ones in the TRS (which are really rather standard).

OTOH, when you do get the M-IV running, you'll be able to run Montezuma Micro CP/M on it, then have the ability to read/write many CP/M formats, including the O1, but that's a whole different issue.

Just don't waste your time tearing down the Osborne, trust me, it won't work.

--T

chuckcmagee
January 20th, 2009, 12:40 PM
All the signals on the bottom go to the same place. So, the fact that the underside is more or less a solid sheet of metal is fine.

chuckcmagee
January 20th, 2009, 12:45 PM
Yes, switching the control boards around would be fine. As we all can see in hires color, they are the same.

Druid6900
January 20th, 2009, 12:47 PM
From practical experience, unless your floppy is unshiended and sitting right next to CRT, it doesn't matter if either of the drives are terminated, they should still work.

Don't touch anything on the FDC board. Turning those pots will detune the circuit and you'll never get them back right without some specialized software.

The speed adjustment is that long blue plastic thing on the edge of the drive PCB.

The TPIs had Tandon mechs and TPI (which I believe Tandy owed, at one time) PCBs.

The drive uses a "cam follower" type of head positioning mech, as described by someone else and the little metal plate they mentioned should have a small ball bearing under it that rolls in the groove on the round plastic part.

Make sure you get all the excess lubricant off the rails.

I sure wish I had those drives here, I could probably have them fixed, aligned and working in about 20 minutes each.

tezza
January 20th, 2009, 12:54 PM
Yes, very different. The Osborne won't see anything on the TRS-80 disk, or vice-versa. Physically swapping out the drives is also not going to work, as the O1 drives are even stranger than the ones in the TRS (which are really rather standard).
--T

This is indeed true. I found that out when I explored using an Osborne drive on the Kaypro, during the drive problem on the latter machine. It seemed very different.

Tez

patscc
January 20th, 2009, 12:56 PM
The connector on the underside of the PCB has everything grounded. The solder blobs are ok. The green stuff is a protective coating over the traces to keep them from oxidizing.

I second Druid6900, don't twiddle the pots with only a multimeter & ttl/cmos switchable logic probe. Better to wait until you know you've a good boot disk, at least.

patscc

Lorne
January 20th, 2009, 01:00 PM
@Druid6900

I haven't turned anything pots on the FDC board (& won't now).

Be careful what you wish for.
I was thinking of asking for a you for a good boot disk.
This keeps going like this, and you just might receive a package in the mail.
BTW - Thanks very much for the offer :)

I'm going to try switching those FDC controller boards.
Any adjustable pots on one board, shouldn't be different for the other one should they?

patscc
January 20th, 2009, 01:04 PM
Lorne asked...Any adjustable pots on one board, shouldn't be different for the other one should they?
The settings are probably different, yes. The pots are there to adjust for component tolerances, in essence.
The pots, by the way, are at least 15-turn pots, so the relative position of the slot means nothing.
patscc

Druid6900
January 20th, 2009, 01:07 PM
Ok, just to straighten out the terminology for you, the FDC controller is that board that the connector was off. The board on the floppy drive is called the drive logic board.

If worse comes to worse and you do have to send them, I have a couple of working, tested and aligned drives in case they are toast.

Wish I had some bootdisks to send you, but, until I get MY Model 4 worked up, I have no way of copying one.

Terry Yager
January 20th, 2009, 01:10 PM
The settings are probably different, yes. The pots are there to adjust for component tolerances, in essence.
The pots, by the way, are at least 15-turn pots, so the relative position of the slot means nothing.
patscc

To clarify, the pots are adjusted to compensate for differences on the logic boards themselves, but should make no difference in swapping the whole board to a different drive.


--T

Chuck(G)
January 20th, 2009, 01:20 PM
The drive speed is also important and check the strobe disk under a flourescent lamp which adjusting the speed control (usually a long blue object on the PCB with a little slot screw on the end)

You get much sharper resolution using either a neon or LED night-light (the cheap LED ones don't have enough filtering to keep them from flickering at 60Hz).


The drive uses a "cam follower" type of head positioning mech, as described by someone else and the little metal plate they mentioned should have a small ball bearing under it that rolls in the groove on the round plastic part.

No, I don't think so--these are taut-band units, not the follower style used on Shugart SA-450s. Take a look at the bottom-side photo.

chuckcmagee
January 20th, 2009, 01:22 PM
I might have misread Dru's post, but these drives don't use the rotating cam trick to move the heads. I see the stepper motor and the metal drive band that moves the head assembly. Well, it doesn't move a large drive cam like the Shugart drives do, anyway.

chuckcmagee
January 20th, 2009, 01:23 PM
Chuckle, I see the two Chucks agree and posted close together too.

Lorne
January 20th, 2009, 01:31 PM
Ok, just to straighten out the terminology for you, the FDC controller is that board that the connector was off. The board on the floppy drive is called the drive logic board.

If worse comes to worse and you do have to send them, I have a couple of working, tested and aligned drives in case they are toast.

Wish I had some bootdisks to send you, but, until I get MY Model 4 worked up, I have no way of copying one.

Thanks for the terminology lesson (I'm making notes as we go)- it's all new, as you can tell, to me.

Let's see if switching the logic board from B to A's FDD works (provided Terry Yager's reply is correct. At least if I have one drive working, I'll know if it's the boot disk or not.

Lorne
January 20th, 2009, 02:07 PM
Let's see if switching the logic board from B to A's FDD works (provided Terry Yager's reply is correct. At least if I have one drive working, I'll know if it's the boot disk or not.

OK I put A's board on the B FDD and tried it.
When the heads were toward the middle, I got a "cass?" message.
When the heads were toward the back, I got a "diskette?" message.
I inserted a disk, and nothing. I don't think the heads moved.

I put B's board on the A FDD and tried it.
When the heads were toward the middle, I got a "cass?" message.
When the heads were toward the back, I got a "diskette?" message.
I inserted a disk, and got a "disk error" message. However, the heads had moved slightly from the back to the middle, because the heads were no longer touching that switch.

I don't know what else to do now, other than get a package ready to ship to Druid6900.

Anyone else have any more comments/ideas?

chuckcmagee
January 20th, 2009, 02:15 PM
I think we have beaten this one to death. Seems like we (you) are at the "let's get this thing outahere". I know I would be at that point also. Don't get me started on trying to get one of my Horizons working. I have been beating on that wall off and on for over 1 year now.

Terry Yager
January 20th, 2009, 02:16 PM
Now you're getting a 'diskette?' prompt? That's a very good sign. At least the computer is seeing the presence of a drive. At this point, my best guess would be, (along with others), a faulty boot disk. My recommendation, do nothing more until you have a known-good disk in hand.

--T

tezza
January 20th, 2009, 02:23 PM
OK I put A's board on the B FDD and tried it.
When the heads were toward the middle, I got a "cass?" message.
When the heads were toward the back, I got a "diskette?" message.
I inserted a disk, and nothing. I don't think the heads moved.

I put B's board on the A FDD and tried it.
When the heads were toward the middle, I got a "cass?" message.
When the heads were toward the back, I got a "diskette?" message.
I inserted a disk, and got a "disk error" message. However, the heads had moved slightly from the back to the middle, because the heads were no longer touching that switch.

I don't know what else to do now, other than get a package ready to ship to Druid6900.

Anyone else have any more comments/ideas?

Hmm..I'm not sure of the significance of the above. I am suprised you get a "cass?" message when the heads are towards the middle though. I would have thought the disk controller would have returned to the back and asked for a disk!

Would the disk controller have issues?

One thought. Can you connect these drives on another machine just to check them? I'm not sure what they would be compatible with (an old PC?), or how you deal with drive selection considering there are no jumpers to select.

The problem could be the disk, the (two!?) drives or the drive controller. We really need to figure out exactly what is faulty. If your very unlucky it could be more than one problem.

There is no-one nearby with a working Model 4 you could visit?

Another option is to try to make a boot disk from one of the emulators detailed at www.trs-80.com. If you have an old MS-DOS PC and a 5.25 360k drive it's possible (apparently).

Tez

chuckcmagee
January 20th, 2009, 02:31 PM
You did say something earlier about getting more boot disks in soon? Waiting until they arrive and trying that last combo where the heads move would be a good next move (cheap anyway). I got out a good flashlight and would sit there with my face about 3 feet above the drive, carefully watching what the head did. Does sound like it is seeking some anyway.

chuckcmagee
January 20th, 2009, 02:37 PM
I just had a "yikes" thought. As we all know, you should NOT get a Cass? prompt when the head is in the middle. It should turn on the drive, move the head backward in single steps until the track 0 microswitch gets tripped, then read the diskette directory and go get the file.

I already noticed that if the "track 0 active" signal is missing, the computer doesn't think there is a diskette drive present. This is very strange behavior!! As in " Floppy Controller is messed up ". And I do mean the floppy controller board, not the drive logic board.

Lorne
January 20th, 2009, 02:43 PM
You did say something earlier about getting more boot disks in soon? Waiting until they arrive and trying that last combo where the heads move would be a good next move (cheap anyway). I got out a good flashlight and would sit there with my face about 3 feet above the drive, carefully watching what the head did. Does sound like it is seeking some anyway.

I've ordered some but haven't heard anything back yet. Not sure when they'll arrive. I requested them from: http://www.trs-80.com/ and I don;t know how long he takes to make/ship them.

The thing that's bugging me, is that the disk heads don't seem to move much. The one that did move off the switch, moved maybe 1/8th of an inch. I think it could be the disk drives.

@Tezza
That seems to be the problem. The heads don't seem to move (or be able to move to the back and ask for a disk. There's just a lot of clicking from what I think is the stepping motor. I don't know anyone else with a TRS-80 and I don't have the hardware hooked up to make a boot disk from an image.

chuckcmagee
January 20th, 2009, 02:52 PM
Time for that flashlight trick.

If the head moves ONE tiny step and dies, what is likely happening is the floppy controller card issues a seek, the microswitch goes off because the head moved slightly in, and then the controller gets totally confused because the beloved "track 0 active" signal goes away.

If the head moves MULTIPLE times before dying, then so much for that theory.

tezza
January 20th, 2009, 02:53 PM
I just had a "yikes" thought. As we all know, you should NOT get a Cass? prompt when the head is in the middle. It should turn on the drive, move the head backward in single steps until the track 0 microswitch gets tripped, then read the diskette directory and go get the file.

I already noticed that if the "track 0 active" signal is missing, the computer doesn't think there is a diskette drive present. This is very strange behavior!! As in " Floppy Controller is messed up ". And I do mean the floppy controller board, not the drive logic board.

This is what I'm wondering too. In all the drives I've played around with, the disk head returns to the beginning to read whatever is on the disk as soon as the drive is activated. Given that BOTH drives exhibit the Cass? behaviour and do not reposition the head, points to a floppy drive controller problem, yes?

Tez

chuckcmagee
January 20th, 2009, 02:54 PM
My thoughts anyway.

Lorne
January 20th, 2009, 03:06 PM
@ chuckcmagee & tezza

I switched the boards on the drives and the same thing happened with both.
They couldn't both be bad, could they. Well, maybe they could, but wouldn't that be unlikely?
That's why I'm thinking maybe the heads aren't moving as they should be. Maybe the stepper motor, maybe gunked up movements (although they look real clean).

chuckcmagee
January 20th, 2009, 03:07 PM
hehe, repeat after me, floppy controller card, floppy controller card. Remember that card mounted inside that had the 4 wire connector that was unplugged? Yes, yes, THAT floppy controller card.

chuckcmagee
January 20th, 2009, 03:10 PM
Of course, I don't have a clear plan of action at this point. Well, I do. Let's replace the floppy controller card. Of course, that is usually pretty tough to do.

tezza
January 20th, 2009, 03:28 PM
Yes, we are not talking about the circuit boards on the individual drives. The floppy controller is not on the drives. It's in the machine itself. It's the thing at the other end of the drive cable.

Tez

Chuck(G)
January 20th, 2009, 03:34 PM
...or the cable/connections. There are 2 movement signals "DIR" and "STEP". DIR specifies the direction; STEP says to do it. It could also be the 7438 drivers, but that would exhibit the same as a bad cable.

In my experience, FDCs don't fail a whole heckuva lot. If that were otherwise the case, I'd be in a world of hurt trying to find another WD1781 for a couple of my systems.

Lorne
January 20th, 2009, 04:11 PM
Oh, crap.
The FDC, not the FDD boards.
That doesn't sound good!

But if it's soldering a few chips, I think I can do that better than I can fixing a drive.

What are the possible problems:
- a bad boot disk (that wouldn't be causing the "cass?" message though, would it?)
- bad FDDs (both of them?)
- bad FDC

Two of you are thinking it's the FDC.
What's the concensus from all the experts?

tezza
January 20th, 2009, 04:14 PM
...or the cable/connections. There are 2 movement signals "DIR" and "STEP". DIR specifies the direction; STEP says to do it. It could also be the 7438 drivers, but that would exhibit the same as a bad cable.

That's a thought. Any sign of damaged/missing pins inside the card connector on the cable at the floppy controller end?

Tez

Lorne
January 20th, 2009, 04:16 PM
I just had a "yikes" thought. As we all know, you should NOT get a Cass? prompt when the head is in the middle. It should turn on the drive, move the head backward in single steps until the track 0 microswitch gets tripped, then read the diskette directory and go get the file.

I already noticed that if the "track 0 active" signal is missing, the computer doesn't think there is a diskette drive present. This is very strange behavior!! As in " Floppy Controller is messed up ". And I do mean the floppy controller board, not the drive logic board.

I think the FDC does try to turn on the drive, and move the heads. I can hear the clicking from the step motor, and I can see the heads jumping in same position like their trying to move. I just think it can't move it because there's too much friction. Maybe I do a small, up close video (with sound) of the heads jumping, and then email it to the interested parties - what do you think?

Lorne
January 20th, 2009, 04:32 PM
That's a thought. Any sign of damaged/missing pins inside the card connector on the cable at the floppy controller end?

Tez

I'll get out my magnifying glass tomorrow, and check that.
I need to do some real money making work now too !
I think I'll do the video at the same time - I still think the heads are trying to move.

chuckcmagee
January 20th, 2009, 04:39 PM
Here's a fun one. Using the configuration you have that is closest to working (drive B hardware, drive A logic board), push the head to somewhere in the middle. Then take a long pensil or something and push down on that little microswitch nub that sticks out and gets pushed down when the plastic slides over it. So, you have the heads in the middle and the switch pushed down. Then turn on or reboot the computer with the diskette in there. See what the head does. It might keep moving towards the center of the drive or might do one of it's clicks and just sit there.

EDIT: NOTE-NOTE- If the head does start to rapidly step towards the front of the drive and keeps stepping, QUICKLY release the microswitch which should stop the head movement. Don't want the thing overdoing it on the higher track movements. Altho, likely has some failsafe mech.

chuckcmagee
January 20th, 2009, 04:44 PM
That kind of stepper motor on my drives is VERY VERY strong! Hard to believe it would have any trouble moving the heads. On the one drive I have, I put it on a regular PC. It grinds away, back and forth to track 0 to get the directory, then back out to read part of the file, jumps a few to get the next part of the file, etc. The stepper motor in your drives is exactly the same kind of motor.

Lorne
January 20th, 2009, 07:07 PM
Here's a fun one. Using the configuration you have that is closest to working (drive B hardware, drive A logic board), push the head to somewhere in the middle. Then take a long pensil or something and push down on that little microswitch nub that sticks out and gets pushed down when the plastic slides over it. So, you have the heads in the middle and the switch pushed down. Then turn on or reboot the computer with the diskette in there. See what the head does. It might keep moving towards the center of the drive or might do one of it's clicks and just sit there.


I don't think I can get anything under a disk to get to the switch, when the disk is in there. Would it do the same thing without a disk, but with the floppy door closed?

Druid6900
January 20th, 2009, 07:32 PM
You get much sharper resolution using either a neon or LED night-light (the cheap LED ones don't have enough filtering to keep them from flickering at 60Hz).

You want the 60 cycle flicker from the flourescent, that's why it's called a 'strobe pattern'. It's even possible to set the speed using incandescent bulbs, if you unfocus your eyes a bit.




No, I don't think so--these are taut-band units, not the follower style used on Shugart SA-450s. Take a look at the bottom-side photo.

You are, of course, correct. The statement should have said "On units with a cam follower (which someone was mentioning)...." I'll leave it in the original post so that your post makes sense.

patscc
January 20th, 2009, 07:35 PM
Lorne, have you had a chance to take your logic probe to anything yet ?
In particular, pin 8 of the floppy cable should pulse when the index hole in the floppy is picked up by the sensor.
Pin 20, head step, should pulse as it tells the head to step in the direction set by
pin 18, dir select.
Time to put the probe to work. (You want it set to TTL level).
Couldn't find a manual for it,so I don't know the specs.
patscc

Druid6900
January 20th, 2009, 07:49 PM
One thing to check for is that the flex-cable between the main logic and the FDC board is in the connectors well. I've seen one end of these come loose before and screw up the signal paths.

You can put these drives in a PC on the cable after the twist and it will, on a full pin cable, default to drive A: (set it in the BIOS as a 360K). On boot-up, it should flash the drive's LCD and, if the head isn't at track zero, reset the drive. You should be able to pull up a directory of a 360K diskette since the directory track is the same even though it's only a SS 35 track drive.

If it works for both drives (one at a time), then the drives are good and it's an FDC problem, in which case, you're screwed.

Chuck(G)
January 20th, 2009, 08:40 PM
[QUOTE=Druid6900;85493]You want the 60 cycle flicker from the flourescent, that's why it's called a 'strobe pattern'. It's even possible to set the speed using incandescent bulbs, if you unfocus your eyes a bit.

Yes, technically, it's 120Hz flicker, since the fluorescent conducts on both half-cycles. But there's a bit of persistence from the phosphor afterglow. A neon has no such persistence (nor does an LED if, as in a typical night light, the LED is run through a half-wave rectifier with very minimal filterintg). The net effect is that the edges of the bars are much sharper and well-defined than with fluorescents. And the strobe trick will *not" work with many newer fluorescents using high-frequency electronic ballasts (or compact fluorescent bulbs for that matter).

patscc
January 20th, 2009, 08:41 PM
Let's hope Lorne can get his hands on a PC old enough to still use edge connectors instead of headers for the floppy connector.
patscc

Lorne
January 21st, 2009, 11:12 AM
Let's hope Lorne can get his hands on a PC old enough to still use edge connectors instead of headers for the floppy connector.
patscc

OK - I bought an old HP Vectra a while ago with the intention of using it to makes disks from images. I've never even started it up.
I am going to now. It's got a hard drive, a 1/2 height 5 1/4" floppy and a 3 1/2" floppy.
I checked - It's got the right power conns for a FDD, but the FDD connectors are 40 pin things.
Screwed again?

chuckcmagee
January 21st, 2009, 11:29 AM
Well, ebay item # 5164718773 I purchased 3 of these cables from the guy. Cost $1 a piece + shipping. They arrived fast and in perfect condition.

If you have some DS DD 5.25 diskettes available, you could try to make more boot diskette images. Or try and image the diskette you already have. See if the image software can read all of it.

Lorne
January 21st, 2009, 12:07 PM
Well, ebay item # 5164718773 I purchased 3 of these cables from the guy. Cost $1 a piece + shipping. They arrived fast and in perfect condition.

If you have some DS DD 5.25 diskettes available, you could try to make more boot diskette images. Or try and image the diskette you already have. See if the image software can read all of it.

The two last available cables are on their way to me.
Thanks.

Lorne
January 21st, 2009, 01:03 PM
What do you think is the best operating system to use on an HP Vectra for doing disk image stuff? Windows 3.11 or Windows 95 ?
Or, can I use something like MS-DOS 6.22 ?

chuckcmagee
January 21st, 2009, 01:06 PM
http://www.classiccmp.org/dunfield/img/index.htm

Looks like Dave recommends straight DOS (in the readme.txt file).

patscc
January 21st, 2009, 01:18 PM
Straight DOS anyday.
Lorne, if the cables don't work, I'll dig through the ol' junk box, PM me if you need a floppy cable.
patscc

Lorne
January 21st, 2009, 01:37 PM
Straight DOS anyday.
Lorne, if the cables don't work, I'll dig through the ol' junk box, PM me if you need a floppy cable.
patscc

Ordered a copy of MS-DOS 6.22 and Windows 95. The Vectra software needs reloading.

Thanks, but I should be OK on cables. I just checked again, and the 40 pin cable I was looking at was going to the 3 1/2" floppy. The one going to the 5 1/4" flopy looks like the one on the TRS-80. I have to take some more stuff apart to get at it and be sure it's exactly the same. I think I'll be leaving the Vectra apart forever, seeing as I'll be needing to make conns all the time.

Now I just need to get the DOS.

patscc
January 21st, 2009, 01:43 PM
Lorne said...Vectra apart forever
Covers are only for when you need to stack computers on top of one another, and they're different sizes, or for when they start interfering with your TV reception. Of course, now with ATSC...

patscc

Chuck(G)
January 21st, 2009, 02:11 PM
Ordered a copy of MS-DOS 6.22 and Windows 95. The Vectra software needs reloading.

Thanks, but I should be OK on cables. I just checked again, and the 40 pin cable I was looking at was going to the 3 1/2" floppy. The one going to the 5 1/4" flopy looks like the one on the TRS-80. I have to take some more stuff apart to get at it and be sure it's exactly the same. I think I'll be leaving the Vectra apart forever, seeing as I'll be needing to make conns all the time.

Now I just need to get the DOS.

Count the conductors in the cable--there should be 34, not 40. 40 is for IDE drives.

Lorne
January 21st, 2009, 02:22 PM
Count the conductors in the cable--there should be 34, not 40. 40 is for IDE drives.

There's 34.
So those cables I ordered should do the trick, right?

chuckcmagee
January 21st, 2009, 02:51 PM
They will. My full sized Gateway tower is using one of those cables as I type. Hooked up to a 5.25" 360K drive even. I am still looking for my 3.31 diskettes. They got pu somewhere and of course, I can't remember where. The Gateway almost boots from the 3.31 floppy but is getting read errors late in the game, which is why I am looking all over the place for another copy.

When you get them, the far end with the 2 connectors on it is for the A drive, the middle 2 are for the B drive and the other end goes to the FDC.

patscc
January 21st, 2009, 03:02 PM
If you plan on hooking the 5.25 from the TRS up to the Vectra, make sure you set the drive to 360k in the BIOS.
patscc

Terry Yager
January 21st, 2009, 03:06 PM
If you plan on hooking the 5.25 from the TRS up to the Vectra, make sure you set the drive to 360k in the BIOS.
patscc

No, 180K. It's single-sided.

--T

patscc
January 21st, 2009, 03:43 PM
Terry Yager said...No, 180K. It's single-sided.
But most BIOS have 360, 1.2, 720, and 1.44 as settings.
It should still work on 360, at least to see if the drive works. I can't remember if you need to load a patch to 'fix' the parameter block so that DOS sees only 1 side, or what.
patscc

Chuck(G)
January 21st, 2009, 03:51 PM
If you're running MS-DOS 6.22 or earlier,

FORMAT A: /1 should do the trick if it's been set as a 360K drive.

patscc
January 21st, 2009, 04:33 PM
And the BPB on the boot record then subsequently tells DOS it's single-sided, right ?
For re-imaging stuff like CP/M disks, though, this shouldn't matter, right ? As long as the BIOS is set to 360k so the controller doesn't start treating the drive as a 1.2 Mb.
I'm wondering, should floppy drive seek in the BIOS be turned on as well, or is it redundant due to the 360k setting ?
patscc

Chuck(G)
January 21st, 2009, 05:09 PM
The BPB will tell DOS not to look for the second side.

Seek can be left either way in the BIOS setup. Just 360K 5.25" selection should be all that's necessary.

tezza
January 21st, 2009, 10:31 PM
Lorne,

You might also consider checking the original boot disk with the program detailed here. http://www.trs-80emulators.com/readdisk_doc.html.

I haven't used it but from what I read, if the program can't read it, there is a good chance the disk is faulty. If it can, it's likely to be ok.

I'm assuming it is one of TRS-80 Dos'es (TRSDOS, LDOS?) rather than a cp/m disk yes?

Tez

Lorne
January 22nd, 2009, 09:43 AM
Lorne,

You might also consider checking the original boot disk with the program detailed here. http://www.trs-80emulators.com/readdisk_doc.html.

I'm assuming it is one of TRS-80 Dos'es (TRSDOS, LDOS?) rather than a cp/m disk yes?

Tez

With patscc's help, I got the Vectra working. It wouldn't boot, so he had me remove the cache ram and reseat it, and then it booted just fine.

The only file on the Vectra's HDD is command.com, so I'll have to wait until I get the Windows and DOS disks (they're in the mail already).

The Vectra has an ethernet card, so once I load an OS, I'll give that readdisk a shot to make sure the boot disk (which is supposed to have both TRSDOS and LSDOS on it) is actually OK.

Lorne
January 22nd, 2009, 12:04 PM
I've ordered some but haven't heard anything back yet. Not sure when they'll arrive. I requested them from: http://www.trs-80.com/ and I don't know how long he takes to make/ship them.


I just received the TRS-80 boot disks in the mail.
I asked Ira for Model IV boot disks, but he sent me 6 disks for Model III, and 6 disks for Model IV, just in case I wanted to access it in Model III mode as well.
That's 12 disks in total, containing TRSDOS v6.2.1-AR, MULTIDOS v2.2 & v5.11, DOSPLUS IV v1.0, LDOS v6.3.1 and a Superutility 4/4P disk, plus all the model III disks, and a couple of games disks as well.

All that for just requesting it. He didn't even ask me to pay for the disks or the postage !
What a good guy (Ira Goldklang - www.trs-80.com)
All Ira asks in return, is that if you're happy with them, you make a donation to his site.
I did.

Now, I think I'll wait until I test the FDDs in the PC, before I insert another DOS disk into the TRS-80.

Lorne
January 22nd, 2009, 12:44 PM
I don't have the necessary cables yet, but I tried changing the BIOS on the Vectra to a 360K 5.25" setting, but i don't appaer to have the option.
In the Phoenix BIOS SEtup - Configuration - Flexible Disk Drives section, it shows A as 1.44 MB, 3 1/2", and B as 1.2 MB 5 1/4". If I try to change either of those, it just gives me the option of it being 1.44 MB or 1.2 MB. No 360 K.

Is that a function of the operating system? IE: does Windows 95 not support a 360 K, while DOS 6.22 might, or do I just have a PC and BIOS that is too new?

Chuck(G)
January 22nd, 2009, 01:29 PM
Nope, it's a function of your BIOS setup program.

However, here's an idea. Set the drive to 1.44MB mode, disable "seek on boot" (if that's an option).

Next unzip the file attached here and copy it onti to your hard disk into theroot directory. Edit your CONFIG.SYS file and add the following:

DEVICE=160DOS.SYS /D:0

Restart your machine into MS-DOS command prompt mode. While the system is booting, you should see a message to the effect of "160K DOS disk in unit 0 is accessible as drive G:" or whatever drive letter is available.

Do a FORMAT G: and watch the fun.

Sick, huh?

Lorne
January 22nd, 2009, 01:40 PM
OK - therein lies the problem.

The HP Vectra PC has a hard drive, a 3 1/2" and a 5 1/4". I have a spare optical drive, but it looks like the Vectra BIOS wouldn't let me hook that up either.

I can download the zip file to my desktop which has a hard drive and an optical drive, but no 3 1/2" or 5 1/4". (someone told me that either the new Dell computers or Windows XP doesn't even support floppies anymore).

Is that correct, or can I add a 3 1/2" to my new Dell desktop? It has a space for one.

patscc
January 22nd, 2009, 01:41 PM
In case you don't have a config.sys on your hard drive, you can create on like this:

At the c:\ prompt, type:

copy con config.sys <enter>
DEVICE=160DOS.SYS /D:0 <enter>
ctrl-Z <enter>

The first line redirects the console to a file.
The second line is content.
The third line closes the file. (hold the ctrl key and type Z, then hit enter)

that'll create a config.sys if you don't already have one there.

patscc

Chuck(G)
January 22nd, 2009, 01:45 PM
OK - therein lies the problem.

The HP Vectra PC has a hard drive, a 3 1/2" and a 5 1/4". I have a spare optical drive, but it looks like the Vectra BIOS wouldn't let me hook that up either.

I can download the zip file to my desktop which has a hard drive and an optical drive, but no 3 1/2" or 5 1/4". (someone told me that either the new Dell computers or Windows XP doesn't even support floppies anymore).

Is that correct, or can I add a 3 1/2" to my new Dell desktop? It has a space for one.

Vista even supports floppies--as does XP. I suspect that Dell being Dell, you can add a single 3.5" floppy to your system (the mobo should have a connector on it for floppy).

If no connector, just plug in a USB floppy drive. Not as flexible as the legacy floppies, but it'll read and write DOS format diskettes.

Lorne
January 25th, 2009, 11:44 AM
The two last available cables are on their way to me.
Thanks.

Those cables from Ebay arrived.
I got the last two that were shown in that auction but the guy told me he has:

I have a case left, about 40 to 50 cables.
Let me know what else you are looking for.
I have some old 486 and Pentium motherboards, AT cases still boxes, AT cases with some computer boards in them.
Some controller cards for RLL, maybe MFM some with cables, some without cables.
Some SCSI controller cards and the older 3.5 size SCSI drives.

I told him he should post them on our forum. Don't know if he will, but if anyone is interested in any of that stuff, PM me and I'll give you his contact info.

Lorne
January 26th, 2009, 03:01 PM
Update:

I got the universal floppy cables, loaded MS-DOS 6.22 onto the PC, and hooked up what was drive A in the TRS-80, to the drive A connector in the PC. Also got Chuck(G)'s 160DOS.sys file off my desktop hard and put it in the root directory of the hard drive in the PC.
I made a config.sys file containing "DEVICE=160DOS.SYS /D:0" as patscc suggested.

I booted the PC.
As Chuck(G) said it would, it gave me a message to the effect of "160K DOS disk in unit 0 is accessible as drive D".

I put a DSDD (not DS2HD) floppy into the drive, and did a format D:

It displayed:
Formatting 160 K
Format complete
Unable to write boot
Format terminated

(FYI: I also did a format D: /1 but then I got a message saying "formatting 180 K), and the following messages were the same as above).

I've taken three videos (each under 1 MB) of the drive stepping through its motions. The first when the heads started in the center of the disk, the next from the outside of the disk, and the last with the drives starting between the center and outside.
The heads don't seem to be able to cover the whole disk (ie: from center to outside).
If anyopne wants to view the videos, please PM me your email address and I'll email them to you as attachments.

Thanks,

Lorne.

patscc
January 26th, 2009, 03:16 PM
With a few wires you can jig something up to let you manually step through the steps and see if it's correctly moving the head. Let me know if you want to go that route.
I can't remember now, have the rails, or anything else on it been lubed ?
I guess after the format terminates, doing a DIR on the floppy gives an error ?
Did you try several floppies ?
patscc

Midwinter
January 26th, 2009, 03:21 PM
Lorne,

Sorry I did not read this thread earlier. I live in Chandler also and had boot disks for the TRS-80 model IV that you could've borrowed instead of waiting for the free ones.

I live right off of Ray & Rural. I don't have much, but you can PM me in the future if you think I might have something you need.

Lorne
January 26th, 2009, 03:53 PM
I can't remember now, have the rails, or anything else on it been lubed ?
I guess after the format terminates, doing a DIR on the floppy gives an error ?
Did you try several floppies ?
patscc

I have lubed the rails in that particular drive.
I haven't tried doing a DIR on the floppy. I will.
I used the same floppy. I'll try formatting some others.

I think it's the drive though - you need to see the video - the heads just don't seem to want to move far.

patscc
January 26th, 2009, 04:00 PM
Total travel is less than an inch (smaller than the window)
I'm thinking maybe your stepper is gunked up, or your drive circuit is bad. You still have that logic probe, right ?
patscc

Lorne
January 26th, 2009, 04:27 PM
I still have the probe (unused).

I tried formatting another disk of a different manufacturer (both disks were new).

Same deal:
Unable to write boot.
I tried DIR afterward.
Message = "Sector not found reading Drive D".

Chuck(G)
January 26th, 2009, 04:54 PM
This wouldn't be the first time that I've seen a bad positioner circuit on a Tandon drive (I know it says, TPI, but it's a Tandon). It seems that Tandon had their share of problems, using 3- 4- and 6-wire steppers on these drives.

In at least one of the cases I've seen, it wasn't the circuitry, but the stepper itself that was at fault. I'd start with the relatively easy task of checking for short or open stepper windings.

patscc
January 26th, 2009, 05:01 PM
Comment out the c:\device=
line, and after you're booted, see if you can do a DIR on an existing 360k (DSDD) DOS floppy if you have one. You can't copy any files, but the FAT( which is needed for DIR) resides on the side of the floppy where your (drive's) single head is.
If you can't pull the DIR, then more work is required.
patscc

Lorne
January 27th, 2009, 12:57 PM
I found a working 360KB DOS disk, so I tried reading that with the TRS-80 drive hooked up to the PC, and it wouldn’t read it.

I managed, after much perseverance, to format a floppy on the TRS-80 drive using Chuck(G)'s 160DOS.sys file in the root directory, and referencing it with patscc's config.sys file.
It formatted it as a 160 KB.
I started copying files to the newly formatted disk.
It copied three files, and then gave me a “Sector not found on Drive D” error.

I’ve been testing and testing the read/write on both the drives.
Same problems on both (although one of them did let me do a format once).

Druid6900 figures the drives are out of alignment – he’s got a PC test jig he uses to align the drives.
So, the two drives are now in a box (well packed for the return trip), and will be on their way to Druid6900 in the morning.

We'll see if the Model 4 works after he sends the drives back.
If it still doesn't work, at least I’ve ruled out the most probable cause, and can then focus my attention on other potential problem areas.

Stay tuned for updates.

Thanks.

Lorne
February 24th, 2009, 06:51 PM
An update on the drives is forthcoming.

I've been informed that we should know the outcome "real soon now".

.

Druid6900
February 24th, 2009, 08:19 PM
An update on the drives is forthcoming.

I've been informed that we should know the outcome "real soon now".

.

Cute, Lorne, REAL cute :)

Druid6900
February 25th, 2009, 08:35 PM
I posted this message in the Rants section in T's Sinus Infection thread as these Model 4 drives seem to get around.

Ya know, it's probably just a coincidence that I got that sinus infection shortly after that bio-terrorist box from Arizona arrived......

Ok, due to time restrains (like everyone bugging me about stuff I'm fixing for them), I only got around to opening the box and working on Drive A (found the envelope and thank you).

However, seeing as the same thing is wrong with both of them, it won't take long to get drive B going as well.

Drive A is happily running a 24 hour read/write burn-in test on a 160K diskette that I formatted on another drive using WinImage. It formatted a bulk erased 160K disk using the F:160 option in the 6.20 format command and DIDN'T format a known defective disk using the same options. Had to touch up the speed JUST a bit.

Seems to be working.

Lorne
February 25th, 2009, 08:51 PM
Ya know, it's probably just a coincidence that I got that sinus infection shortly after that bio-terrorist box from Arizona arrived......

However, seeing as the same thing is wrong with both of them, it won't take long to get drive B going as well.

Drive A is happily running a 24 hour read/write burn-in test on a 160K diskette that I formatted on another drive using WinImage. It formatted a bulk erased 160K disk using the F:160 option in the 6.20 format command and DIDN'T format a known defective disk using the same options. Had to touch up the speed JUST a bit.

Seems to be working.

In case the germs are still active (after all this time :) ), please make sure the drives are disinfected before you send them back.

"the same thing is wrong with both of them" - don't keep us in suspense - what was wrong with them? (other than they were screwed).

Cheers,

Lorne.

Druid6900
February 26th, 2009, 07:50 PM
Drive B has replaced Drive A in the 24 Hour read/write burn-in and, after a couple of more days of tests (I like to be thorough) they will be on their way back to their case.

Yup, like I said, a light dusting with nerve gas should do it.

Well, as far as I could determine, the problem was that they didn't work :)

Lorne
February 26th, 2009, 08:19 PM
Drive B has replaced Drive A in the 24 Hour read/write burn-in and, after a couple of more days of tests (I like to be thorough) they will be on their way back to their case.

Yup, like I said, a light dusting with nerve gas should do it.

Well, as far as I could determine, the problem was that they didn't work :)

That's good news on the drives getting back home - it'll be in the mid-80's (30 C) here tomorrow, so they'll be looking forward to coming back :)

I think there are a few folks on our forums that will want to know what was wrong with those drives.

I trust you'll provide us a slightly more detailed explanation of the problem once they're done?

Thanks.

chuckcmagee
February 27th, 2009, 02:42 AM
That's why I just love this forum. Everyone does subtle sarcasm SO well :p:cool:

Druid6900
February 28th, 2009, 08:59 PM
I trust you'll provide us a slightly more detailed explanation of the problem once they're done?



Fine, more detail.

They wuz broke.

I fixed 'em REAL good.

Happy?

Terry Yager
February 28th, 2009, 09:06 PM
Fine, more detail.

They wuz broke.

I fixed 'em REAL good.

Happy?

No! What size hammer did you use? ...and was a Bowie Knife utilized?

--T

Druid6900
February 28th, 2009, 09:08 PM
No! What size hammer did you use? ...and was a Bowie Knife involved?

--T

The Ultimate Avenger size and only momentarily :)

patscc
February 28th, 2009, 09:11 PM
I'd chatted with Lorne about the drives earlier, and I don't think the diagnosis of "They wuz broke" is entirely accurate.
I think "dey war'd messed-up" would be more accurate.
patscc

Lorne
March 1st, 2009, 05:45 AM
I fixed 'em REAL good.

Happy?

I'm very happy they're fixed, and I'm looking forward to getting them back, and into the Model 4.

Just a thought: if you're ever planning a career change, try to avoid applying for anything with the words "technical report writing skills" in the job description! :)

Thanks Dru,

Lorne.

chuckcmagee
March 1st, 2009, 06:15 AM
Drive B has replaced Drive A in the 24 Hour read/write burn-in and, after a couple of more days of tests (I like to be thorough) they will be on their way back to their case.

Yup, like I said, a light dusting with nerve gas should do it.

Well, as far as I could determine, the problem was that they didn't work :)

Hmm, are floppy drives really designed for a 100% duty cycle for that rather long period of time? Of course, I never worked in the computer repair shop at my jobs, I was too busy putting new RAID drives in the servers to keep up with storage demands.

Druid6900
March 1st, 2009, 08:17 PM
I'm very happy they're fixed, and I'm looking forward to getting them back, and into the Model 4.

Just a thought: if you're ever planning a career change, try to avoid applying for anything with the words "technical report writing skills" in the job description! :)

Thanks Dru,

Lorne.

Well, looks like I'm gonna hafta fix Drive B gooder because, although the original problem is fixed, I'm getting sporatic read/write errors on it and it don't go out 'til I'm happy with the way it's working.

Hey, boy, whatchu sayin' 'bout my rightin' skilz?

If you're going to be noisey about it, both drives had dried out stepper motor bearings. The nice thing about having the units in front of you is you can touch them and, moving the heads was a chore all along the length. It's not something I've seen before, but, that's what it was.

A little precision placement of 3-in-1 on both ends of the stepper motor shaft and then moving the heads by hand fixed this up nicely and then cleanup of the shaft ends with some denatured alcohol to prevent gunk buildup.

I regularly run floppy drive for 24 hours without any apparent ill effects.

Drive A is working perfectly, according to my diagnostic and alignment programs, but, I'm going to have to figure out what is up with Drive B.

chuckcmagee
March 2nd, 2009, 12:26 AM
Reminds me of that old joke --

WHAT! $250 just to fix it by hitting it with a hammer???

Hey, you gotta know where and how to hit it!!!

Druid6900
March 2nd, 2009, 07:36 PM
I'm thinking that Drive B has a flaky 3470 read/write amp and that was probably the ORIGINAL problem. The steppers just dried out from sitting for years baking somewhere.

They are hard to come by, but, I believe I have a/some 3470s kicking around, it's just a matter of finding it/them.

Druid6900
March 2nd, 2009, 07:41 PM
Reminds me of that old joke --

WHAT! $250 just to fix it by hitting it with a hammer???

Hey, you gotta know where and how to hit it!!!

Yup, it's a buck for hitting the part and 249 bucks for knowing which part to hit :)

Terry Yager
March 2nd, 2009, 09:22 PM
Yup, it's a buck for hitting the part and 249 bucks for knowing which part to hit :)

And, you have to have a fancy-schmancy professional-grade hammer calibrated to the exact striking force, and laser-guided to land in the correct spot for optimum performance. Those kinda tools don't come cheap, y'know.

--T

Lorne
March 3rd, 2009, 05:11 AM
I'm thinking that Drive B has a flaky 3470 read/write amp and that was probably the ORIGINAL problem. The steppers just dried out from sitting for years baking somewhere.

They are hard to come by, but, I believe I have a/some 3470s kicking around, it's just a matter of finding it/them.

I've got a couple of dud Tandon drives here, so if you can't find the parts, and it's something (I don't even know what a 3470 looks like - it's a chip?) that I can pull off one of these, let me know. (Or, I can replace your parts with the ones from these later).
Thanks,
Lorne.

Druid6900
March 3rd, 2009, 12:50 PM
I've got a couple of dud Tandon drives here, so if you can't find the parts, and it's something (I don't even know what a 3470 looks like - it's a chip?) that I can pull off one of these, let me know. (Or, I can replace your parts with the ones from these later).
Thanks,
Lorne.

Yes, it is an 18-pin IC and, on the TPI board, it was the only one socketted (what does that tell you?)

Suddenly, they don't seem to be so hard to find and not very expensive at all.

Give me some time to confirm that's the problem and then I'll sacrifice one of the ones I have to fix it.

Chuck(G)
March 3rd, 2009, 02:05 PM
Unicorn's got 'em for $0.99 the each (look under "Motorola"). Shouldn't be hard to find otherwise, both Moto and TI made a jillion of them.

patscc
March 3rd, 2009, 02:13 PM
That would be this Unicorn, since the other one only has the NTE part for $7
http://198.170.117.30/IC/MOTOROLA.html
patscc

Lorne
April 2nd, 2009, 05:46 PM
Another Update:

The drives are on their way back to me.

Druid got Drive A working with some lube and TLC, but he figures that the Drive B stepper motor was just too siezed up. He figures it must have been sitting somewhere in a humid climate for a long while and got corroded (that certainly didn't happen here!).

Once I get them back in the Model 4, I'll make one more post to (hopefully), say everything is working fine.

Lorne
April 6th, 2009, 07:02 PM
Got the drives back from Druid today.

I put them in back in the Model IV, powered it up, and at the "Diskette ?" prompt, I inserted a boot diskette.

Then I saw a screen I'd never seen before - ie: it booted !

Druid done fixed 'em real good !

Thanks for all the help folks.

This thread can now be considered closed.

.

tezza
April 6th, 2009, 08:50 PM
Cool! Glad it's all working.

Tez