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Early-ish IBM PC boards - need a few IDs - comments welcome

syzygy

syzygy

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Joined
Apr 22, 2023
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Location
North East USA
With more whim than need, I bought a small cache of boards [$50+$15s+3t]. They looked clean and I could identify, and use, a few of them. So, I figured I would bid and if they went for much more, I would be fine. I was the only one who bid! I am happy. They are all *very* clean and really look new. I'm just starting to do some research but I know there is a lot of experience and expertise on here and am hoping for some identification/information/opinions.

1. Serial/Parallel board. Run-of-the-mill and I even scored a manual courtesy of @modem7. Easy enough for me to test out.
ser_par IMG_2989.jpg

2. MDA I have seen some with 1981 date coded chips. This one is early but not that early. Still, very nice condition, even the edge card teeth are clean. Again, easy enough for me to test out.

MDA 1983 IMG_3005.jpg

3. Like it says, 256K memory, but I have not seen these before because I never had a real IBM PC :) I need to learn more before I try to test this one out - my clone has 640K on the MB and I don't want to just slap this board in there without knowing more. Notice that 317 regulator on the board?
I256K mem MG_2992.jpg

4. I don't know. There are two boards connected. I have seen pics of an IBM PGA that were connected but they didn't look like this. This does look like a video board of some kind.

connected IMG_3012.jpg
After some careful examination, I eased the boards apart.
4.a
con brd 1 IMG_3009.jpg

4b (has a 9 pin connector on the edge, 84/85 date code chips)
con brd 2 IMG_3014.jpg
5. Obviously a power supply board. If you look here, you will see some of the identical numbers on that PS and it's from an IBM S/36 5364. I wonder if the last two boards could be from one of those?
PS IMG_3017.jpg

6. ?
unk 1 IMG_2994.jpg

7. ?
unk b 2 IMG_2998.jpg

They also came with two IBM anti-static cases, which are quite cool.
 
jafir said:
4 seems to be the video card for a 3270 PC.

Click to expand...
It certainly does. That tip led me to wiki, which says "It includes a video card which occupies 1-3 ISA slots (depending on what level of graphics support is required), and supports CGA and MDA video modes. The display resolution is 720×350, either on the matching 14-inch color monitor (model 5272)[2] or in monochrome on an MDA monitor.

That led me to this thread on here which linked a product book.

Slowly but surely. :)
 
#3 is right here: https://minuszerodegrees.net/5150_5160/cards/5150_5160_cards.htm the one marked "IBM 256KB Memory Expansion Option". I picked one of these up on fleabay to use in my 5150. But wound up using a different card. Those modules that are in it are very strange creatures that use multiple voltages. The cards and definitely the modules are not all that common that I've seen so be careful with that. That spot above on the link on modem 7's site has all the info you'll ever need about the card. It can only be used to backfill you up to 640k. It cannot do anything like add umbs or any such thing.
 
4a seems identical to the All Points Addressable adapter. Even the drawing is the same, except there is only one square cap and not two as in the drawing. The installation is clear about the top card connector and so on. It is *very* close but the part numbers are different; my card is silk screen pt. no . 1503156 and paper tag 6236008, their installation doc shows 6322657, but I swear the board diagram is nearly identical.
 
sorphin said:
#3 is right here: https://minuszerodegrees.net/5150_5160/cards/5150_5160_cards.htm the one marked "IBM 256KB Memory Expansion Option". I picked one of these up on fleabay to use in my 5150. But wound up using a different card. Those modules that are in it are very strange creatures that use multiple voltages. The cards and definitely the modules are not all that common that I've seen so be careful with that. That spot above on the link on modem 7's site has all the info you'll ever need about the card. It can only be used to backfill you up to 640k. It cannot do anything like add umbs or any such thing.
Click to expand...
Yep! Alas, conventional memory only.
 
Still working on #6 and #7. The reverse side of #6 has a bunch of signal names.

IBM unk 2 rev IMG_2999.jpg

Does this jog any memories? Old Teletype, keyboard?
 
syzygy said:
Still working on #6 and #7. The reverse side of #6 has a bunch of signal names.

View attachment 1270297

Does this jog any memories? Old Teletype, keyboard?
Click to expand...

The ASIC has me a bit confused for the date-code ('1039') - but the '9314' means it was produced in Bromont, Canada ('93' plant code) and Burlington, Vermont ('14' plant code), but that is a very common IBM sequence on chips. The FRU ('1440834') is impossible to look up without a letter on the third character instead.

I have 3270 PC units (actually, an excess of the display adapters), but interested in your intentions...
 
IBMMuseum said:
The ASIC has me a bit confused for the date-code ('1039') - but the '9314' means it was produced in Bromont, Canada ('93' plant code) and Burlington, Vermont ('14' plant code), but that is a very common IBM sequence on chips. The FRU ('1440834') is impossible to look up without a letter on the third character instead.

I have 3270 PC units (actually, an excess of the display adapters), but interested in your intentions...
Click to expand...
My intentions are honorable (mostly) :)

I have tested the serial/parallel board and it works fine. I will bay it for $20 I guess.

I have also tested the The MDA and it works completely, including the par port. It took me quite a while to test it because I am using one of these and I had to fiddle with a bunch of values - geometry and such. I may keep that. Even though my initial pc-clone had a herc adapter and not an MDA.

The main display board and all points addressable board for the 5271/3270 PC will probably be bayed for $40 for both, when I can find a box. There is no way I can test those and while I did see an untested 3270 for $300, I don't think I am up to it - too many unfinished projects.

I can't test the 256K board and bayed it for $25 I think.

I want to know what the two unknown boards are! A fellow on CPU world identified the 40 pin on #7 as likely an 8048. Not a peep on #6. I have spent hours on bitsavers looking through manuals but no joy so far.

I think the anti-static cases are cool - with the IBM logo and in such good shape. Probably keep those unless I get an attack for too-much-stuff-itis.

All-in-all it has been a good learning experience.
 
syzygy said:
My intentions are honorable (mostly) :)

I have tested the serial/parallel board and it works fine. I will bay it for $20 I guess.

I have also tested the The MDA and it works completely, including the par port. It took me quite a while to test it because I am using one of these and I had to fiddle with a bunch of values - geometry and such. I may keep that. Even though my initial pc-clone had a herc adapter and not an MDA.

The main display board and all points addressable board for the 5271/3270 PC will probably be bayed for $40 for both, when I can find a box. There is no way I can test those and while I did see an untested 3270 for $300, I don't think I am up to it - too many unfinished projects.

I can't test the 256K board and bayed it for $25 I think.

I want to know what the two unknown boards are! A fellow on CPU world identified the 40 pin on #7 as likely an 8048. Not a peep on #6. I have spent hours on bitsavers looking through manuals but no joy so far.

I think the anti-static cases are cool - with the IBM logo and in such good shape. Probably keep those unless I get an attack for too-much-stuff-itis.

All-in-all it has been a good learning experience.
Click to expand...
Sounds like great plans - The 3270 PC display boards are able to output to an MDA monitor if needed (that was the low-end submodel configuration), but as you say, a bunch of work to test.
 
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