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DOS lives on!!
April 23rd, 2012, 01:19 PM
My most exciting score I got at the E-Waste event was my IBM PC AT. But of course, the one I most wanted to work doesn't work.

When turned on, the computer comes to life, but it it doesn't beep, the floppy drive doesn't engage, and nothing comes up on the screen. Also none of the keys will respond on the keyboard, which is working. (The keyboard from my XT.)
I have removed the cards one by one, turning the AT on after each removal and it still doesn't work. Also, (only on this computer), the monitor makes a high pitched squealing sound when the computer is on. It doesn't do that on any of the other computers it's connected to.

Any suggestions as where to start?

ChrisCwmbran
April 23rd, 2012, 01:26 PM
I guess you need to check the voltages being output by the PSU.

The highpitched whining sound is often a defective capacitor isn't it?

DOS lives on!!
April 23rd, 2012, 01:32 PM
The highpitched whining sound is often a defective capacitor isn't it?
I'll check the power supply voltages. The monitor works great, but it only makes the whining sound when the video cable is connected to this 5170.

Stone
April 23rd, 2012, 02:06 PM
Any suggestions as where to start?This isn't going to solve all your problems but start with an AT keyboard. :-)

SpidersWeb
April 23rd, 2012, 02:39 PM
Well first I'd try another video card, just in case and check the voltages from the PSU.

But failing that are you able to burn EPROM's?
If so, fit a CGA or MDA card and use the Lansoft ROM images here: http://www.minuszerodegrees.net/rom/supersoft.htm (5170 at the bottom)

Certainly the quickest way to find faults as it brings up the display much earlier in the test sequence.
Could also try piggy backing memory chips in bank 0 in case one of them is faulty- I prefer Lansoft because it gives you better direction and memory piggy backing can be rather time consuming (I find it frustrating) - where as Lansoft will tell you what is wrong (unless it's something core, like the CPU).

Edit: also on minuszerodegrees check out 5170 under DRAM here http://www.minuszerodegrees.net/failure.htm - one of those cheap POST cards could tell you something

Maverick1978
April 23rd, 2012, 02:39 PM
Check minuszerodegrees.net for further info. Make sure to pull all of the expansion cards but video and see what happens. Check if you have a Type 1 board (piggybacked ram is the tell-tale sign). If you do - congrats! - it doesn't lock you into using IBM-only floppy/HD controllers. And also congrats - you probably have something as simple as a bad RAM chip of the piggy-back variety (if you have a bad ram chip, your machine will do exactly what it's doing now - mine did; it had 3 bad chips)

Of course make sure to press in all socketed chips first, yadayada... Good luck!

DOS lives on!!
April 24th, 2012, 01:22 PM
My 5170 does have the Type 1 motherboard, and also has the piggyback RAM chips. I tried just the video card inserted, and it still has the problem.

So now I begin pulling them out one by one and hoping I find the culprit.......

DOS lives on!!
April 24th, 2012, 02:10 PM
I've already pulled out three of the four rows of chips and still the problem persists. The fourth row is not easily accessible due to the metal piece that the speaker is attached to and guides the cards. Is there a way to remove this piece?

modem7
April 24th, 2012, 02:41 PM
I thought that you were going to measure all of the voltages (including the POWER GOOD line) !


The fourth row is not easily accessible due to the metal piece that the speaker is attached to and guides the cards. Is there a way to remove this piece?
No. It's part of the chassis. If you have to, remove the motherboard.


I've already pulled out three of the four rows of chips and still the problem persists.
On a type 1 motherboard, bank 0 is the 2 rows of RAM at the front of the machine, and bank 1 is the next 2 rows.
The type 1 motherboard will not start up if bank 0 has been removed (or has bad RAM chips).
Removal of bank 1 as a diagnostic activity is valid.

You could try swapping banks 0 and 1, but that will only work if all the chips in bank 1 are good.

I suggest that you measure the voltages soon. It's a good step 1.

barythrin
April 24th, 2012, 02:46 PM
Actually after checking the power supply check the processor. Failing to POST is failing somewhere before the bios can even get read or function. Bad RAM should give you beep codes, bad video would normally do the same.

mikey99
April 24th, 2012, 03:12 PM
Sometimes the 5170 battery packs will leak onto the motherboard.

Is the motherboard clean in the area around the keyboard connector ?

modem7
April 24th, 2012, 03:18 PM
Bad RAM should give you beep codes,
On a 5170 type 1 motherboard, an early POST test is that of the first 64K of RAM (which of course resides in bank 0).
Failure of the test results in the POST sending a repeating series of codes to any POST card that is plugged in (set to port 80h).
The codes are shown in the 'Dynamic RAM Chips' section at http://www.minuszerodegrees.net/failure.htm
No beeps are issued.

Failure of RAM after 64K (a later POST test) is displayed on-screen.

Le_Bear
April 24th, 2012, 06:34 PM
I've had some success in reviving dead boards by removing everything removable, including the battery, power supply, all cards, everything, and letting the board set, overnight or longer(sometimes it doesn't take that long, but in some cases it did) and then putting it back together again very slowly, step by step.

DOS lives on!!
May 7th, 2012, 07:58 AM
OK, so the power supply is outputting the correct voltages. The motherboard is clean of battery leakage. When I remove Bank 1 of the piggybacked memory, the computer still has the same symtoms. I was told of a diagnostic EPROM I could burn, but I do not have an EPROM burner.

Can anyone recommend a good POST card and/or EPROM burner? Since it seems that there is a faulty RAM chip in Bank 0, I'd need the card to identify the sore thumb.

Stone
May 7th, 2012, 08:34 AM
Since it seems that there is a faulty RAM chip in Bank 0, I'd need the card to identify the sore thumb.Seems like it would be simpler to just switch the banks of ram and see if you get lucky and that 1 has good ram where 0 doesn't. From there it would be much easier to isolate the bad chips if there are any.

Maverick1978
May 7th, 2012, 08:43 AM
Stone's spot-on... It's a bit of a pain, but it's what you have to do. If you can, go get 2 or 3 "new" RAM pieces from ebay. Then swap those in one at time... Start with swapping in place of chip 1 in bank 0, then attempt to boot. If it still doesn't post, then put back in the original, and swap the new into chip 2 and power it up again. Wash/repeat until you get to the end of the bank, or until you get a successful boot. If you're lucky, you'll only have the one bad chip in bank 0 and it'll boot. If you're like me, you'll end up with a bad chip in bank 0 and two bad in bank 1, and you'll have some REAL fun with chip swapping :)

FWIW, while it's a pain, it's not really that time-consuming... I think that Chromedome45 and I had mine working 100% within 20 minutes, and that was with two bad chips in the same bank, which required some extra guesswork and trial/error with the chip swaps.

DOS lives on!!
May 9th, 2012, 01:08 PM
Making some progress! I found the faulty RAM chip, which was the third chip in Bank 0. Now when I start the computer, it emits two sets of two short beeps and the screen still stays blank. What do those beeps mean?

Stone
May 9th, 2012, 01:21 PM
It means you need to get the display working, because that's where the error code is being displayed. It's a POST error. This is assuming you have a true IBM BIOS.

It's gonna be one of these:

http://www.personal.psu.edu/~sab139/postcode.htm

My guess is that it's a 2xx error, probably a 201, IOW you still have memory problems. Did you stop searching after you found that bad chip? :-)

Chuck(G)
May 9th, 2012, 01:31 PM
You mean beep-beep followed by beep-beep?

DOS lives on!!
May 9th, 2012, 01:33 PM
I reseated the display card and now it makes 1 long beep and two short beeps, then the second set of two beeps. And also there is this switch on the motherboard, being able to set it to C76 or SW1. What is that switch for?

It also makes the same beep code when the video card is removed.

Stone
May 9th, 2012, 01:40 PM
1 long, 2 short = Video (Mono/CGA Display Circuitry) issue.

Here, read this... thououghly. There is a jumper for memory size and other issues you need to be aware of to make any progress:

http://www.vintage-computer.com/vcforum/showwiki.php?title=Systems:IBM+PC+AT+5170

DOS lives on!!
May 9th, 2012, 02:14 PM
I've now got the jumpers set to the right settings. Now when the computer is turned on, it only emits two short beeps.

Stone
May 9th, 2012, 02:28 PM
Once again, when you get your display working you'll know what the error is.

SpidersWeb
May 9th, 2012, 03:30 PM
Have you tested the video card + display on another machine recently?
Just a stab in the dark, you're not using one of those EGA / VGA combo's and it's set to use the wrong port by chance?

DOS lives on!!
May 9th, 2012, 04:00 PM
It did end up being a faulty video card. I swapped one out from my 5160, so now I'll have to find an EGA graphics adapter for this 5170. Thanks everyone!

Stone
May 9th, 2012, 04:36 PM
You mean you didn't check that first? Duh!

DOS lives on!!
May 9th, 2012, 04:54 PM
Well, at least it's working now.:D I should've checked that first, but the first thing I thought was wrong with it was the RAM, so I went to that first.

Now I just need to find an EGA adapter and two piggybacked RAM chips to take the bad one's place.

Stone
May 9th, 2012, 04:57 PM
I think you can make a 128 by gluing two 64s together.

DOS lives on!!
May 9th, 2012, 05:04 PM
Well there's the problem, I don't have any extra 64 or 128s laying around, so that's why I'm seeing if anyone has any to spare.
And while I'm at it, I'm also in want of 9 RAM chips to fill up the third bank in my AST SixPak Plus card.

Stone
May 9th, 2012, 06:07 PM
I'm also in want of 9 RAM chips to fill up the third bank in my AST SixPak Plus card.What size are they?

modem7
May 9th, 2012, 07:09 PM
Now I just need to find an ...... and two piggybacked RAM chips to take the bad one's place.
See http://www.vintage-computer.com/vcforum/showthread.php?30457-Piggyback-RAM-chips-for-IBM-5170


I think you can make a 128 by gluing two 64s together.
No, it is not as simple as that. Piggbacked chips are slighlty different to one another.

modem7
May 9th, 2012, 07:14 PM
And while I'm at it, I'm also in want of 9 RAM chips to fill up the third bank in my AST SixPak Plus card.

What size are they?
The SixPakplus manuals at http://www.minuszerodegrees.net/manuals.htm contain lists of known compatible RAM chips.

Mark2000
May 9th, 2012, 07:42 PM
Piggy back ram - all you can eat: http://www.ebay.com/itm/IBM-AT-286-Piggyback-Memory-Ram-IC-ZA1250-ZA1250NL-/380313354802?pt=LH_DefaultDomain_0&hash=item588c714232

And you're in luck: IBM EGA board with fully loaded daughter mem board: http://www.ebay.com/itm/IBM-5170-EGA-Card-with-Duaghter-Board-and-Correct-Dip-Switches-for-EGA-/200756478239?pt=US_Vintage_Computing_Parts_Accesso ries&hash=item2ebe04c11f

marcoguy
May 9th, 2012, 07:46 PM
Is that board good for 5160s? It looks like it uses an 8 bit ISA slot.

modem7
May 9th, 2012, 08:05 PM
Is that board good for 5160s?
Yes, it is.

marcoguy
May 10th, 2012, 01:44 AM
Hmmmmm... Might have to bid on that! :D

DOS lives on!!
May 10th, 2012, 02:54 AM
Hmmmmm... Might have to bid on that! :D
NOOOOO! I don't want my 5170 to be stuck being a B&W TV with a hard drive.:D

Thanks for those links Modem7 and Mark2000. It all just turned out to be one faulty RAM chip and a faulty video card.

modem7
May 10th, 2012, 04:52 PM
I have added this motherboard failure to my list at http://www.minuszerodegrees.net/vcf_motherboard_failure_history.htm

SpidersWeb
May 10th, 2012, 06:32 PM
I have added this motherboard failure to my list at http://www.minuszerodegrees.net/vcf_motherboard_failure_history.htm
I'll check details when I get home, but I've had two shorted caps on my 5160 so far, I will find the C numbers for you.
Also two dead 5150 boards - both undiagnosed, one definately isn't DRAM or CPU but Lansoft wont start, the other didn't respond to DRAM swaps but didn't try Lansoft on it.

DOS lives on!!
May 21st, 2012, 05:52 PM
The two new memory chips came in today. I replaced the bad chip with a good one, but the computer still only counts 256kb of RAM, even though both banks are populated. I did set the jumper on J18 to indicate that 512kb is installed on the computer. What's causing it to ignore Bank 1?
(And for the IRC folks, the RAM error message is gone.)

One more thing. The AST SixPak Plus (short) manual says that if the computer has an existing 512KB of onboard RAM, then the highest amount of RAM the SixPak can have is 128KB, thus totaling 640KB. Does this mean that the SixPak will ignore all but 128KB of the RAM it has? It is fully populated and I'm trying to get the computer to use it's RAM combined with the SixPak's RAM.

marcoguy
May 21st, 2012, 05:55 PM
Well, you would need some form of an EMS driver to go over 640k with any card.

DOS lives on!!
May 21st, 2012, 06:03 PM
OK, is there any specific one I should use for this AT or SixPak Plus? And most importantly, will most applications be able to use the added memory that the EMS driver provides, such as Windows 1.0, Wordstar, MS Lan Client, drivers.

marcoguy
May 21st, 2012, 06:10 PM
Well, I don't really know. My knowledge only goes as far as the fact that a driver is needed. I have never used a SixPak plus. As a matter of fact, I have not yet even used EMS on an older PC. That is on my to do list, though. I'm not sure if the SixPak plus was designed for EMS, even.

modem7
May 22nd, 2012, 12:02 AM
The two new memory chips came in today. I replaced the bad chip with a good one, but the computer still only counts 256kb of RAM, even though both banks are populated. I did set the jumper on J18 to indicate that 512kb is installed on the computer. What's causing it to ignore Bank 1?
On my early 5170 (piggybacked RAM), which has both banks fitted, if I erroneously set the CMOS SETUP to 256KB of base RAM, then on startup I see the 5170 count up to 512KB (and then I get a '164-Memory Size Error' error). It's counting up to 512KB. So we can rule out an incorrect RAM setting in CMOS SETUP.

Please confirm that J18 is set per the following photo. Just to make sure.

http://www.minuszerodegrees.net/images2/5170_J18_512MB.jpg

modem7
May 22nd, 2012, 12:14 AM
One more thing. The AST SixPak Plus (short) manual says that if the computer has an existing 512KB of onboard RAM, then the highest amount of RAM the SixPak can have is 128KB, thus totaling 640KB. Does this mean that the SixPak will ignore all but 128KB of the RAM it has? It is fully populated and I'm trying to get the computer to use it's RAM combined with the SixPak's RAM.
The SixPakPlus (both versions) is an 8-bit card. There will there be a performance hit by using an 8-bit RAM card in a 16-bit machine.
Also, the SixPakPlus is not described by AST as being compatible with the AT. There may be issues, some subtle.
You really need to find a 16-bit RAM card.

modem7
May 22nd, 2012, 01:50 AM
If you've confirmed per above (post #44) that J18 is set correctly, then some experimentation of mine reveals another possible cause for your 5170's symptoms.

On my 5170, in which all 512KB is good, if I configure the CMOS SETUP for 256KB base RAM, I see a '164-Memory Size Error' message. In this scenario, the logic in the BIOS/POST appears to be, "Well, I'm told that there is 256KB RAM, but RAM past 256KB is testing good. That should not be the case. There is a problem."

However, if I then remove a chip from bank 1, I see what you see - a count up to 256KB with no errors whatsoever. The logic in the BIOS/POST appears to be, "Well, I'm told that there is 256KB RAM and when I try a memory test on addresses past 256KB, they fail. Therefore I'm seeing what I expect to see. All is good."

So, if you have configured the CMOS SETUP for 256KB base RAM, then there is one of the causes of the symptom. The CMOS SETUP needs to be reconfigured for 512KB base RAM. Once you've done that, you will probably see a 201 memory error showing you which bit (or bits) in bank 1 have failed.

Stone
May 22nd, 2012, 02:49 AM
The SixPakPlus (both versions) is an 8-bit card. There will there be a performance hit by using an 8-bit RAM card in a 16-bit machine.
Also, the SixPakPlus is not described by AST as being compatible with the AT. There may be issues, some subtle.
You really need to find a 16-bit RAM card.I've got a NIB NOS Intel Above Board Plus with manual and software still shrinkwrapped. And, the board is fully populated with 2 mb.

8998 8999

DOS lives on!!
May 22nd, 2012, 03:06 AM
Once I get the diagnostic disk for this AT, I'll change the base memory setting to 512KB. Although I thought it would automatically recognize it with the jumper change, but I guess it allows the SETUP program to find the added memory.

Also, the SixPakPlus is not described by AST as being compatible with the AT. There may be issues, some subtle.
You really need to find a 16-bit RAM card.
This disappoints me. I'm sure the previous owners read the manual too.

I've got a NIB NOS Intel Above Board Plus with manual and software still shrinkwrapped. And, the board is fully populated with 2 mb.
That would be a good fit for my AT. How much would you like for it?

Stone
May 22nd, 2012, 03:42 AM
$60 shipped via Priority Mail.

DOS lives on!!
May 22nd, 2012, 02:50 PM
I set the base memory in the BIOS to 512KB, and guess what, the error returns. It's a 040002 8100 201-Memory Error, followed by a: 164-Memory Size Error. Probably because the faulty chip isn't reporting itself. Time to run the system checkout.

Stone
May 22nd, 2012, 02:56 PM
Like modem7 said above, you've still got a bad chip in bank1.

DOS lives on!!
May 22nd, 2012, 03:10 PM
That's what I've been doing for a while now, and I found the other shot chip. It was chip 8 in Bank 1. Now the error message no longer appears and it counts 640KB of RAM!

DOS lives on!!
May 26th, 2012, 06:03 PM
Well the error came back again. Somehow in the last time I booted it, it counted 640KB of RAM, but this boot it only counted 512KB. So I went back into the BIOS setup and changed it to 512KB. The error went away on the next boot.

Also today, I installed Windows 1.01 on it. It runs great. I enjoyed playing Reversi, or Isrever.

marcoguy
May 26th, 2012, 06:09 PM
Where do you get Win1.x? All I have ever found is $100+ Ebay auctions. I want to play Isrever too!:D

Stone
May 26th, 2012, 06:46 PM
I have a copy of it but it's just that -- a copy, not the originals.

Caluser2000
May 26th, 2012, 07:21 PM
Why play them in windows when there are pure Dos variants :p

marcoguy
May 26th, 2012, 07:24 PM
I've wanted to try it for a really long time now. It won't read a mouse in VMs, so I have been looking for a reasonably priced original copy for about a year now. I posted a thread on it too.

modem7
May 27th, 2012, 12:33 AM
Well the error came back again. Somehow in the last time I booted it, it counted 640KB of RAM, but this boot it only counted 512KB. So I went back into the BIOS setup and changed it to 512KB. The error went away on the next boot.
It sounds like you had a failure of RAM in the 512K to 640K region (supplied by your SixPakPlus I presume), and the 5170 warned you of the error.

DOS lives on!!
May 27th, 2012, 03:10 AM
Marcoguy, I got the exact copy of Windows 1.0 that's on my 5170 here (http://www.mirrors.org/archived_software/www.techknight.com/esa/default.htm).

marcoguy
May 27th, 2012, 04:47 AM
Thankyou, but I have no way to write that to floppies until I get my 5160 on the net with Arachne.