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nekonoko
July 26th, 2008, 02:16 PM
Hello!

I recently picked up a TRS-80 Model II (the one with the big 8" disk drive). It did come with some software, but the disks apparently haven't aged well and the original TRSDOS diskette no longer boots. The backup TRSDOS diskette does boot, but I'm unable to copy it (bad sectors).

Does anyone here have the capability to make TRS-80 Model II boot diskettes? I'd love to play with the machine some more, but I'm afraid I'll kill off my only TRSDOS backup if I use it too much. Also wouldn't mind sourcing CP/M for the machine ;)

kb2syd
July 26th, 2008, 03:20 PM
I can email you images that you can then make with your own PC. See the directions at:
http://www.classiccmp.org/dunfield/img/index.htm

Kelly

nekonoko
July 26th, 2008, 03:50 PM
Well the images would be a great start, thanks!

Hmm - anyone already have an 8" drive setup on a PC that can create disks from image files? Unfortunately I don't have a PC with that sort of hardware around here. I do have a box of brand new, still in shrinkwrap, 8" Model II floppies though so blanks shouldn't be a problem.

billdeg
July 26th, 2008, 08:34 PM
Hi - Please make sure you have a terminator installed or you'll not be able to boot, regardless of the disks

nekonoko
July 26th, 2008, 08:54 PM
Yep - terminator pack is installed at the back of the machine.

I am able to boot the machine just fine, I just don't have a backup of my TRSDOS diskette, so if something happens to it I'm sunk.

dano
September 11th, 2008, 07:29 PM
You may want to see about getting LS-DOS from Tim Mann's site. I have the same problem, Model II with no disks (not even non-working ones) and was thinking of going this route.

-Dan

nekonoko
September 11th, 2008, 11:03 PM
Ah thanks - wasn't aware of LS-DOS. I do have disk images for TRSDOS for the Model II as well (from Dave Dunfield's site), but I haven't come up with a solution for creating the 8" diskettes yet. Looks like LS-DOS will be a similar story.

billdeg
October 4th, 2008, 06:42 PM
I had not used my model II for three years, and with this thread in mind I set up the old beast for a routine test. I try not to let any working system go too long before I re-run for a few hours to refresh the electronics.

Anyway...I must have waited too long, she does not boot any more. The system powers up,but will not attempt to read the disk drive and there's nothing sent to the CRT.

So far I have done little other than open the system and quickly inspect it. The CRT tube fires up (strong glow), so I assume that the issue lies with one of the four system cards (there is no motherboard). I have not done any further testing.

If I have an update I'll post it.

Bill

billdeg
October 5th, 2008, 06:29 PM
Update: I have made progress. I re-seated the chips and checked the connections. Now I at least get a boot attempt screen.

Upon booting the system with a disk in the drive that I believe should work I get:
BOOT ERROR DC
...These are disks that I believe worked in the past, I am assuming that they *all* can't be bad now considering I have used them in the past few years. The disks have been in proper storage. After this message appears the drive stops spinning and the light goes out as expected. I think the controller is OK, or at have no reason to believe it's bad. If I insert a disk backwards the system realizes and shows me the message ENTER DISKETTE or similar. The system also will immediately attempt to boot the disk installed in the drive.

I think what I'll try next is to replace the disk drive. Fortunately I have a new or close to new replacement drive on hand.

bottom line - I have no way to make or test Model II boot disks at the moment.

Druid6900
October 5th, 2008, 08:47 PM
From the Model II TechRef Manual;

"11. "DC Error" if the floppy disk controller is still busy or seek error is indicated or drive not restored to track 0"

Try moving the drive head back to the rear of the drive in a powered off condition. It might be sticking before it gets to track zero

Sharkonwheels
October 6th, 2008, 01:19 AM
Pete, just because I ran into it, hms104 on eBay has original manuals - and she is a dream to deal with.

Model II manuals (http://cgi.ebay.com/VINTAGE-RADIO-SHACK-TRS-80-OWNERS-OPERATIONS-MANUAL_W0QQitemZ220287009869QQcmdZViewItem?hash=it em220287009869&_trkparms=72%3A1205%7C39%3A1%7C66%3A2%7C65%3A12%7C 240%3A1318&_trksid=p3286.c0.m14)

T

Terry Yager
October 6th, 2008, 08:07 AM
If your disk(s) have gone bad, it sometimes returns the same error code. Even if the disk works in another machine, a dirty head will make it harder to read in this one (I know you know all this, but others reading this might appreciate the info).

--T

Lou - N2MIY
October 13th, 2008, 05:07 PM
Today the kids had off from school today, so we made a day trip to my favorite surplus place in Kingston NY - P&T Surplus.

There I saw a Model II sans keyboard. Actually, it looks like it has been there for a long time. I just thought I'd mention it if anyone was looking for one (or parts).

Lou

Chuckster_in_Jax
October 27th, 2008, 04:52 PM
Upon booting the system with a disk in the drive that I believe should work I get:
BOOT ERROR DC
...

Fired up my Model II and Model 16 today. Got the same "BOOT ERROR DC" on both. The diskettes I use were purchased off of eBay within the last 8 months and look new. On the Model II you can hear the head loading but not the sound of the heads stepping through he tracks. The Model 16's drives don't seem to make any sound.I have a project to hookup two 5 1/4" floppies to the external connector and try that since apparently they are more reliable than the 8". Got one of those FDAP cards awhile back and initially hooked an 8" floppy up to a 450Mhz Pentium machine running DOS. It accessed the 8" drive and formatted the floppy OK. I may need to set this up again and test out the drives in the Tandy computers.

Chuckster_in_Jax
October 27th, 2008, 08:08 PM
Found the Operations Manual online for the Model II'

http://maben.homeip.net/static/S100/tandy/model%20II/Tandy%20Model%20II%20Operation%20Manual.pdf

alker
March 2nd, 2009, 06:08 AM
Hi - Please make sure you have a terminator installed or you'll not be able to boot, regardless of the disks


Hi, I also tried to fire up one of my Model II's.. I cleaned the heads of the drives.. and finally I could load a TRSDOS disk.. but when I enter the date I always get the message "BAD Response" and I should enter the date again... I have no idea what it could be.. the drive seems to read the disk at it starts up.. I never heard of this terminator.. should it be installed on the back of the Model II?

Chuckster_in_Jax
March 2nd, 2009, 07:03 AM
Hi, I also tried to fire up one of my Model II's.. I cleaned the heads of the drives.. and finally I could load a TRSDOS disk.. but when I enter the date I always get the message "BAD Response" and I should enter the date again... I have no idea what it could be.. the drive seems to read the disk at it starts up.. I never heard of this terminator.. should it be installed on the back of the Model II?

If you get as far as the OS prompting for the date that is a good sign. The fact that you get a message "Bad Response" would seem to indicate a keyboard or keyboard cabling problem. There is a terminator block that should be installed on a connector in the rear of the unit labeled "disk expansion". It is similar to a terminator that SCSI uses on the last drive in a chain. Terminators for the Model II are very hard to come by, so if you don't have one, you may have to make one.

kb2syd
March 2nd, 2009, 07:56 AM
Or you're entering a date it doesn't like.

Try something like 03/02/1986 or 03/02/86

They are NOT Y2K aware.

alker
March 2nd, 2009, 09:59 AM
yes of course I enter a date around the 80's.. but I have one point more.. it displays "enter date ......... (9 points) .. so I enter f.ex.

01/01/1982. and there is still one . available.... I tried everything to come by.. but I'm too stupid..

I also tried another keyboard and it did not help.. maybe really the terminator is the problem?!?!

Chuckster_in_Jax
March 2nd, 2009, 06:57 PM
What keyboard are you using? It should say Model II on it. I'm not sure if any other keyboard will work.

Terry Yager
March 2nd, 2009, 09:06 PM
What keyboard are you using? It should say Model II on it. I'm not sure if any other keyboard will work.

Yes, the Model 16 board will work with it too (not the 16B).

--T

nekonoko
March 5th, 2009, 10:58 AM
I never heard of this terminator.. should it be installed on the back of the Model II?

For reference, the terminator looks like this:

http://www.nekochan.net/~neko/images/PICT1616.jpg

Druid6900
March 6th, 2009, 07:32 AM
Yeah, and like the port covers on Model Is, it was the first thing to be lost......

billdeg
March 6th, 2009, 08:30 AM
It would be easy enough to make one by plugging a couble staples in the right holes. It's probably only one or two jumpers needed, but it looks more complicated because it has to fit on the port. Someone with a continuity tester could check theirs, and let us know. This info may be somewhere on the web already, given that there are many model II's still out there without terminators and this question must have come up before!
bd

hexsane
March 7th, 2009, 10:37 AM
My Model II does not have one but I was able to boot with a 5.25" floppy drive. Could this be because the 5.25" drive is terminated?

Terry Yager
March 7th, 2009, 03:35 PM
My Model II does not have one but I was able to boot with a 5.25" floppy drive. Could this be because the 5.25" drive is terminated?

Prob'ly. To use the external drive(s), the terminator was removed, and the last drive on the chain was terminated.

--T

alker
March 9th, 2009, 05:50 AM
My Model II does not have one but I was able to boot with a 5.25" floppy drive. Could this be because the 5.25" drive is terminated?

are there any informations available on the used diskette drive inside the Model II? f.ex. jumpering infos... I assume there are shugart 851 drives inside the II; but on mine there are only labels of "Texas Peripherals" and nothing else.. also google'ing did not help me to find more informations on these drives..

alker
March 10th, 2009, 12:25 AM
I found out that the Model II uses 2 different boards for the disk drives. I have here 4 model II's and 2 of them have cards with 2 connectors; 2 boards have only one connector for FDD. On the board with 2 connectors one connector directly goes to the internal drive; and the 2nd connector goes to the expansion port. On the other boards only 1 cable goes to the internal drive and then directly to the expansion port.

I also found out that my problem with "Bad response" was due to a failing disk; an other disk worked now and I could boot into TRS-DOS.
But only one of my 4 internal drives can read disks (it boots now into TRS-DOS and also into CP/M). From the other 3 drives 2 have always a seek error (I exchanged the FDD boards, tested with external drives a.s.o) and in the 3rd drive the stepper motor does not move anymore.

I believe the seek error comes from either a wrong alignment or the head does not read anymore. I cleaned the heads.. but no result (the 4th drive was working again after I cleaned the head).

Are there any informations around how to clean / align 8 inch drives to make them read again and to overcome the "seek error"? Any help would be appreciated.. thanks!

hexsane
March 10th, 2009, 01:50 AM
I found out that the Model II uses 2 different boards for the disk drives. I have here 4 model II's and 2 of them have cards with 2 connectors; 2 boards have only one connector for FDD. On the board with 2 connectors one connector directly goes to the internal drive; and the 2nd connector goes to the expansion port. On the other boards only 1 cable goes to the internal drive and then directly to the expansion port.


Check to see if the terminator is in the drives on the Model II's that have the cable running from the drive to the expansion port. My guess is they are not there.

alker
March 11th, 2009, 01:20 AM
I rould bring back to life my 2nd 8 inch drive: I cleaned the head several times with tape cleaning fluid.. and suddenly the drive could read some of my 8 inch disks.

As mentioned before I have 4 TRS-80 Mod II with drives; I tested now every combination and it seems that the external jumper is not necessary to read or boot to CP/M and TRS-DOS. I exchanged the drives, controllers .. hours of hours.. and the remaining SEEK error of my 3rd drive seems to be a result of wrong alignment (maybe wrong jumper-setting on the board).

I have drives with a Shugart label inside and other drives with Texas peripherals label (but nothing else). They also use different boards; the mechanics is nearly the same. In my 4th drive the stepper motor does not move.. but it seems tricky to part this stepper motor and the reading head out of the drive to use it in my 3rd drive.

Is there any documentation / manual around for these 8inch drives used in the TRS-80 Mod. II?

Chuckster_in_Jax
March 11th, 2009, 02:47 AM
As mentioned before I have 4 TRS-80 Mod II with drives; I tested now every combination and it seems that the external jumper is not necessary to read or boot to CP/M and TRS-DOS. .

Is there any documentation / manual around for these 8inch drives used in the TRS-80 Mod. II?

My Model II has a Shugart SA-801 drive. As I remember there is a jumper block on the 8" drive's main board. Setting the jumper on a couple of pins will enable termination on the drive. That may be why you are able to boot OK with the internal drive. I have the documentation for the Shugart SA-801 and posibbly a User's Guide and a Service Manual for the Model II in electronic format. I'm here at work right now, so it would be tonight before I could get back to you with those.

Chuckster_in_Jax
March 11th, 2009, 03:29 AM
Found the documentation for the Shugart SA-801 drive:

http://www.bitsavers.org/pdf/shugart/50575-4_SA800_Maint_Feb78.pdf

Look on page 29. There is a table that shows what the jumper settings are for. I am a little confused because there are several terminations, not just one. There may be more info in the User's Manual or Service manual for the Model II.

Micom 2000
March 11th, 2009, 06:55 PM
I had a lot of problems bootng my m.II years ago until I ran across a post from Fritz Chowolka or one of the other european M.II gurus. The Tandy 8" drives had a problem in detecting the last sector or something. Holding down the drive lockng bar allowed it to complete the reading. There was a fix for this problem but I haven't a clue where you can fnd it. All I remember is that holding down the drive locking mechanism worked for me.

Lawrence