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IBM AT Power Supply issues

Well, the new caps have gone in in place of the old ones and success! The machine fires now up good as gold.

So, now to the setup phase to check if either of the two hard drives are ok.

paul said:
Well, the type 1 has the Full AT sized motherboard which was a unique design at the time, while the Type 2 has the Baby AT size based on the XT. You can still fit any standard Baby AT motherboard in your IBM case, should it ever become necessary. My AT is a type 2 but I've owned a few type 1's in the past.

I would suggest being more diligent of ESD safety with this board, based on having a couple fail in the past when we used them as print servers at work.

Jaycar still sells the correct drop-in replacement AT CMOS battery if you haven't improvised. Anything from 3V up will work.
Click to expand...

Thanks for the info Paul. Good to know about the replacement battery. I didn't know that!

Regarding the setup disks, the answer is no, I don't have them. I'll have to locate an image somewhere.

Gotta run. The significant other is nagging me to go somewhere.

Tez
 
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First generation 5170: Type 1 motherboard running at 6 MHz
Second generation 5170: Type 2 motherboard running at 6 MHz
Third generation 5170: Type 2 motherboard running at 8 MHz

"Generation" is my terminology, not IBM's. My 5170 is also a first generation. Each generation had its own version of BIOS. See http://www.vintage-computer.com/vcforum/showthread.php?t=12995 to see what each BIOS supported. Hard drive type support is limited; instead, you could use the AMI BIOS shown at the bottom of http://members.dodo.com.au/~slappanel555/bios.htm (I can post you programmed EPROMs).

The major options from IBM for the first generation 5170 are:
1. 360KB drive for B:
2. 128MB memory board which fills the 512KB to 640KB space (IBM describe as "128KB Memory Expansion Option").
3. 512MB memory board to to provide 512KB extended memory (IBM describe as "512KB Memory Expansion Option").

Motherboard schematics for type 1 are at http://members.dodo.com.au/~slappanel555/misc/schematic_5170_motherboard_type_1.pdf (typo in first page: 512MB instead of 512KB). I have schematics for certain cards.

tezza said:
... (drives, 2MB memory card, video card, parallel card, serial card) the PSU is fine.
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Note that if your "parallel card, serial card" are the IBM ones supplied in 5150 and 5160s, IBM indicate that they are not suitable for a 5170.

tezza said:
Regarding the setup disks, the answer is no, I don't have them. I'll have to locate an image somewhere.
Click to expand...
A generic setup program suitable for the 5170 is at http://members.dodo.com.au/~slappanel555/software/GSETUP.ZIP
Alternatively, if your okay with typing code into BASIC, you can use the program referred to at http://www.vintage-computer.com/vcforum/showthread.php?t=15197
 
I've got the self-extracting image of the AT diagnostics diskette from the IBM BBS. It's bigger than 100K, so I'll need an emal address if you'd like it...

I've never seen a PC (or Compaq) serial card that won't run on a 5170 (or a 386). Compare the BIOS code in the 5150 and 5170 for the RS-232C services and they're the same. Just keep the speed under 9600 bps.
 
Chuck(G) said:
I've never seen a PC (or Compaq) serial card that won't run on a 5170 (or a 386). Compare the BIOS code in the 5150 and 5170 for the RS-232C services and they're the same. Just keep the speed under 9600 bps.
Click to expand...
There can be other issues. For example, some PC cards have a problem running at the higher bus speed of the AT. We may never know why IBM indicated that it's serial card from the 5150/5160 isn't compatible with the 5170, we just need to keep in mind that the OEM has said, "don't do it".
 
It’s been a good day. Thanks for all the help and information. I’m nearly there. The capacitor replacements on the disk card did the trick, and the setup resources modem7 pointed me to quickly allowed me to zap the bios with the correct info.

BTW, this system has a 1.2MB floppy drive and TWO hard drives, a massive (in physical size, not capacity) 20MB Seagate ST-4026 and a ½ height 40MB ST-251.

Ultimately, I want to configure this machine with a 1.2 and 360k drive, and the 20 MB ST-4026 HD with MS-DOS 3.3 installed. I figure this would have been a fairly typical configuration when it came out, yes? Although I’ve dropped an 8bit VGA card in at the moment so I can use my LCD screen for testing, it came with CGA. I might see if I can upgrade that to EGA, although getting EGA monitors is not easy. I might just snag an EGA card to start.

Here is the front of the naked beast. Dead ugly without the faceplate, and the ½ height HD is normally a bay higher . That 20MB one in the middle is huge and heavy.

2009-08-15-the-naked-AT.jpg

​

The ST-4026 seems dodgy. It had DOS on it but wouldn’t boot. I did a MSDOS 6.2 scandisk and it found 8 bad sectors. I did the same on the ST 251 and found 1 bad sector.

I feel it would probably be worthwhile to low-level format the 20MB drive. Are others of that opinion? The manual for my Disk controller says this regarding low-level formatting:

"Use of the IBM Advanced Diagnostic (or similar program for IBMcompatibles) is necessary since these controllers contain no on-board Basic Input/Output System (BIOS) ROM"

That would explain why DEBUG -g=c800:5 didn't work!

Does anyone know where I might get the Diagnostic disk or files mentioned above?

Tez
 
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modem7 said:
There can be other issues. For example, some PC cards have a problem running at the higher bus speed of the AT. We may never know why IBM indicated that it's serial card from the 5150/5160 isn't compatible with the 5170, we just need to keep in mind that the OEM has said, "don't do it".
Click to expand...

Very early serial cards for the 5150 used the NSC 8250, rather than the 8250A, which had its own problems, which may have been the foundation for the IBM's remark.

Unlike IBM's mainframe gear, I generally do not consider the engineering on the 5150-5170 to be representative of their best efforts.
 
tezza said:
Ultimately, I want to configure this machine with a 1.2 and 360k drive, and the 20 MB ST-4026 HD with MS-DOS 3.3 installed. I figure this would have been a fairly typical configuration when it came out, yes?
Click to expand...

Sounds good.

Here is the front of the naked beast. Dead ugly without the faceplate, and the ½ height HD is normally a bay higher . That 20MB one in the middle is huge and heavy.
Click to expand...
Beauty is in the eye of the beholder :)
Yeah, the ST225 is certainly worth keeping on hand in case the full-height disk fails. I have a ST-4038 in mine - but no MFM spare :( and these will be extremely rare here in Kiwiland. No faceplate is normal for the ST-4026 as used in the AT and those blue ribbon cables with yellow tape are the originals.

All you appear to be missing is the blank for the second floppy. I picked up an IBM 1.2 MB floppy locally as a spare, you might be really lucky and find a 360. As you might know the 360 KB IBM part has a small asterisk molded on the front panel.
The ST-4026 seems dodgy. It had DOS on it but wouldn’t boot. I did a MSDOS 6.2 scandisk and it found 8 bad sectors. I did the same on the ST 251 and found 1 bad sector.
Click to expand...
Not to worry (too much) - that's fairly normal and the bad sectors need to be manually written out. There should be a table printed on the top of the drive with the originally-found bad sectors listed. Also, do you have the AT drive type set to 2?
I feel it would probably be worthwhile to low-level format the 20MB drive. Are others of that opinion?
Tez
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Low-level formatting on these things is not difficult, nor necessarily a one-time thing. It can be done non-destructively too, e.g. to change the interleave. I've emailed you Disk Manager, see how that goes. There is another one I use, diag.exe, maybe someone else has that handy?

EDIT: Tez, the folder I emailed you has the "diag.exe" utility included which will allow you to check for bad sectors and low-level format the drive with those written-out. That's not part of the Disk Manager utility but I had put it in the same directory for my backup. You don't need to use DM for this.
 
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Well, all the testing and configuring is now done. Thanks to tools provided by modem7, Paul and Chuck(g) I now have a fully configured, working and tested IBM AT.

I've carried out a low level format, locked out all bad sectors (there were a dozen or so) and installed MS-DOS 3.3.

For now I decided to leave the spare HD in the machine. My 360K drive wasn't a matching one in colour or looks and it degraded the appearence. The half-height HD (configured as D) fills up the space underneath the 1.2 MB one nicely.

The final job is to clean it all then reassemble. It's grubby ESPECIALLY the keyboard and monitor.

Thanks guys for all your help, both the hints on the hardware repair and files and info for setup. I don't know how many of us could persue this hobby without the Internet and the good people connected to it.

I'll post some pics later in the week, when I re-assemble and clean up everything.

Tez
 
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Thanks for the feedback. I enjoy writing up the projects when they are finished, and hope that people do get something out of them.

Tez
 
tezza, would PC DOS 5 be a good candidate for your AT? i have some disk images (actually IBM DOS, but I think IBM changed the name) and you can have at them if you want.
 
Thanks but I found a copy of PC-DOS 3.1 in my archives, once I had a good look. It's now loaded with that.

Tez
 
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