[sdiy] socket question
The Old Crow
oldcrow at oldcrows.net
Tue Jun 25 22:53:22 CEST 2002
On Tue, 25 Jun 2002, Chris Stecker wrote:
> Some of you know that I'm the proud/frustrated owner of a unique 2-part
> Buchla 400 ("by Kimball") with an intermittent boot failure / warmup
> problem. The thing will almost never boot straight out of the gate, but
> if I turn it on and let it run for 20-30 minutes, then go to (re)boot
> it, it will work, almost as if it had to "warm up." Generally, once it
> boots correctly, it's A-OK for the rest of the session, rebooting into
> alternate operating systems with no difficulty. More recently it's been
> not wanting to boot at all, regardless of how long it "warms up" or
> whether I've been using it. Witness the all-afternoon struggle and 20
> minutes of actual operation we milked out of it at AHMW.
This is reminiscent of my old S-100 CP/M machine. Too many sockets have
aged poorly due to the heat/cold cycles while in storage. I've even
found chips popped up or even out of sockets due to this. I replaced most
of the sockets with the beryllium/copper turned-pin type (and used an
Xacto blade to clean the film of oxidation off chip pins). Some chips I
remember having to strap down with tie-wraps looped under the socket
frames, mostly EPROMs.
> My question: is the problem with socketed IC's likely to be caused by
> oxidation, such that I could use some "de-oxit" to restore the
> effectiveness of the socket connection, or not? Is there some reason
> that pulling the chips and trying a blast of de-oxit on each connection
> would be a bad/dangerous idea?
I personally have found this to be a lot more hit-and-miss than simply
replacing the sockets. If there are any 4000-series parts used, replace
them with new ones. Bipolar logic should still be fine.
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