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Pictures of Compaq Portable III Expansion Chassis Card?

T-Squared

T-Squared

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May 29, 2011
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San Antonio, TX
I have had a bit of an idea. The Expansion Chassis is extremely rare and expensive, but the parts for the expansion card seem to be easy enough to source, to build a custom version for those of us who don't have the dough to buy an original. The connector on the back of the Compaq Portable III or 386 is a 96-pin mating connector. All I need is multi-angle pictures of what the card looks like, and a picture of what the rest of the parts are on it.
 
Hi.

I had a similar idea and was able to locate schematics at https://forum.classic-computing.de/...le-386-expansion-unit-schaltplan-und-connect/

I created a simple bracket to hold the connectors for a wire-wrapped version here:
www.thingiverse.com

Compaq Portable III / Portable 386 Expansion board Bracket by bryanc806

This is a bracket and cover so that you can make your own Expansion chassis for the Compaq Portable III and presumably Portable 386 computer. The Expansion chassis is very difficult to find. I found a pinout for the connectors here...
www.thingiverse.com www.thingiverse.com
 
@Mike1978 , I saw your question on Thingiverse. I have not don't anything but build and use mine. I briefly considered doing a PCB layout, but that's not my forte. A dual-card one would be possible, but I didn't do that to keep the size down. With 2 cards, the strength of the attachment becomes more important. I _think_ it should be possible to print a cover for 2 short cards, but most 3D printers have a smaller bed that keeps you from printing a single-piece cover.

--bryan
 
bryanc806 said:
@Mike1978 , I saw your question on Thingiverse. I have not don't anything but build and use mine. I briefly considered doing a PCB layout, but that's not my forte. A dual-card one would be possible, but I didn't do that to keep the size down. With 2 cards, the strength of the attachment becomes more important. I _think_ it should be possible to print a cover for 2 short cards, but most 3D printers have a smaller bed that keeps you from printing a single-piece cover.

--bryan
Click to expand...
Hi @bryanc806 ,
Could you perhaps share pictures of the board you created and how you laid it out. Perhaps my knowledge of how to translate what is in the kicad document to be able to build a board is lacking. Hopefully @raymondh can share this. The ram board to me seems just as necessary. I’m hopefully going to get a second machine with both ram and extension present so I can share pics of both if required.

Keep up the good work guys!

Mike
 
Mike1978 said:
Hi @bryanc806 ,
Could you perhaps share pictures of the board you created and how you laid it out. Perhaps my knowledge of how to translate what is in the kicad document to be able to build a board is lacking. Hopefully @raymondh can share this. The ram board to me seems just as necessary. I’m hopefully going to get a second machine with both ram and extension present so I can share pics of both if required.

Keep up the good work guys!

Mike
Click to expand...
I wire-wrapped mine. It's tedious, but for a one-off project it worked fine. The photos are on thingiverse.

I had a DIN-96 connector that was wire-wrappable (~12mm long pins), and a ISA connector that I had de-soldered from an old motherboard. Not much else but follow the schematic.

--bryan
 
Hi Bryan, ah I see now. Sorry I completely saw this wrong on the last visit to Thingiverse. I saw the pcb of the network card and though incorrectly you had designed a board.

Now I understand it. Maybe it is something I can attempt then if I order the parts..

Thanks for the clarity, I’d read and re-read the post multiple times but my mind had seen just the pcb of the network card and the connector and I completely misread what it is you had done. Man that does look fiddly!

I’m wondering if there is some easier way to interface this with some sort of ribbon connector.. but these are fine pitch connections
 
Mike1978 said:
If you make a pcb could you share the files? I’m also hoping someone could perhaps make a ram expansion card as they seem rare to locate.
Click to expand...
I would love to make a ram expansion card clone. But without one and without the model/mem backplane that will be hard to do.
 
Mike1978 said:
Hi Bryan, ah I see now. Sorry I completely saw this wrong on the last visit to Thingiverse. I saw the pcb of the network card and though incorrectly you had designed a board.

Now I understand it. Maybe it is something I can attempt then if I order the parts..

Thanks for the clarity, I’d read and re-read the post multiple times but my mind had seen just the pcb of the network card and the connector and I completely misread what it is you had done. Man that does look fiddly!

I’m wondering if there is some easier way to interface this with some sort of ribbon connector.. but these are fine pitch connections
Click to expand...
A ribbon cable would be difficult as the pin pattern on the DIN-96 connection is not excessively uniform. I think laying out a board would be more straightforward.

In truth, I was a couple of hours of wire-wrapping for me. I had a couple of minor goofs to resolve, but nothing excessive.

As for the ram expansion, I think it would be possible. Probably easier if someone has an example card to inspect. The connector is not something I'm familiar with. It's fairly high density and lots of pins (at least for the 1980s).

--bryan
 
bryanc806 said:
A ribbon cable would be difficult as the pin pattern on the DIN-96 connection is not excessively uniform. I think laying out a board would be more straightforward.

In truth, I was a couple of hours of wire-wrapping for me. I had a couple of minor goofs to resolve, but nothing excessive.

As for the ram expansion, I think it would be possible. Probably easier if someone has an example card to inspect. The connector is not something I'm familiar with. It's fairly high density and lots of pins (at least for the 1980s).

--bryan
Click to expand...
I have one on the way. It appears to be 84 pins with a pin pitch of 1.27mm and a row spacing of 2.54mm.
 
raymondh said:
I've created a Github repository for the boards I am working on recreating. So far I have upload the schematic of the ISA chassis https://github.com/raymondh2/CompaqPortableIII-PCBs/tree/main/CompaqPortableISACHASSIS
Click to expand...
Oh wow have you managed to create a working expansion. Any photos?

I managed to get an expansion pack with a second machine but sadly the plasma isn’t in a good state on the donor. Secondly it also came with the ram expansion so was a win win for my initial machine so I have the official two isa slots one of which I’ve added a network card.
 
Incredible so are there gerbers and bom files for these? I suspect there’s a few Compaq 3 users would love these hard to acquire components. Did you build these yourself or have them manufactured ?

I got lucky with finding a machine with these in
 
Mike1978 said:
Incredible so are there gerbers and bom files for these? I suspect there’s a few Compaq 3 users would love these hard to acquire components. Did you build these yourself or have them manufactured ?

I got lucky with finding a machine with these in
Click to expand...
The Kicad files are in the repository above linked by @raymondh. I had the PCBs fabbed at JLCPCB, put them together with parts sourced from a variety of places though mostly Mouser, then struggled with remembering the difference between extended/expanded/xms/ems/himem etc etc works!

I guess I got the other luck with finding a cheap ISA expansion chassis!
 
silvervest said:
The Kicad files are in the repository above linked by @raymondh. I had the PCBs fabbed at JLCPCB, put them together with parts sourced from a variety of places though mostly Mouser, then struggled with remembering the difference between extended/expanded/xms/ems/himem etc etc works!

I guess I got the other luck with finding a cheap ISA expansion chassis!
Click to expand...
I was hoping that was both parts and they could be ordered prebuilt. Still it’s a great progress.
 
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