Altair - DB25 mounting - thick panel

Jeff G jeffg at
Wed Jun 24 12:30:42 EDT 2020

So an update to my previous "Altair can't jump" thread - turns out it was
something on that serial board, as I was finally able to get a 88-2SIOJP
from Martin Eberhard, and it works great and the Altair CPU had no problems
whatsoever running CPM, Basic, and a variety of other software I threw at
it. I'm amazed at how awesome these reproduction boards are for these
things (my Altair had ONLY a cpu board in it). I do plan to revisit that
card though as I can now use the monitor on the 2SIO to test/troubleshoot
it much faster than toggling 60+ bytes every time.

Next question - I went to mount the DB25 serial ports into the back of the
cabinet, to find that the panel is pretty thick, and really prevents the
plugs from connecting properly with the locking screws (screwnuts?) in
place. (I'm coining that word!) It also seems like the nut part of the
screw would have to be half as deep to compensate for the thickness of the
panel. I can grind it down but then it'd only leave a couple threads left.

I think I can overcome this using the serial cables included with the 2sio
card by actually mounting them on the outside surface, if I can find some
longer screwnuts that would go all the way through the housing and the
panel. Something like this but maybe a hair longer:

Anyone else have any other ideas though? I'm good with IDC connectors and
ribbon cable so could always use a different connector. I think i've seen
some older uber-deep DB25s and now I know why they existed lol.

Jeff aka Bags

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