[sdiy] socket question

[The Old Crow]

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.

Crow
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