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IBM Expansion Unit

gerrydoire

Veteran Member
Joined
Aug 25, 2008
Messages
1,145
Anyone have a spare IBM Expansion Unit to give too a poor vintage computer collector down on his luck? :rolleyes:
 
I don't know the rarity of them in the US, but in Norway, my guess is that there isn't any left at all. Everybody I'm asking tell me they threw out their old computers years ago. If there was any expansion units at all, they have problably been thown out too.
 
Guys - ever consider making an expansion unit? They are pretty well understood, and there are lots of books on ISA bus interfacing out there, some of which even talk specifically about expansion units.
 
Guys - ever consider making an expansion unit? They are pretty well understood, and there are lots of books on ISA bus interfacing out there, some of which even talk specifically about expansion units.

If anybody does, make sure to include the system clock signal so the expansion unit would be syncronized with the sysyem unit!
 
That's kind of a requirement, just as important as sending the data and address lines out.

One thing that is optional that can be regenerated in the expansion chassis (and not sent over the wire) is the OSC signal. That just needs to oscillate at a particular frequency, and does not need to be in sync with the system board OSC signal. SCSI cards are big users of the OSC signal.
 
Hmm.... I never thought of BUILDING an expansion box... Well, with no experience in making cards, I'd probably screw it up pretty bad. I think that most peoples main thing is authencticity.

Eric, I appreciate the mention, but edit your post to include this on my name instead of the one you've got there already. It took me to NathanAllan's profile, lol.

--Jack
 
Authenticity might be a goal. For some of us (PCjr owners in particular), just getting a usable machine was a big goal.

There are some expansion box projects for the PCjr, and they are all based on the PC expansion chassis.
 
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