[sebhc] Re: H8 data record format

Patrick Rigney patrick at vintagecomputermarketplace.com
Thu May 6 21:32:38 CDT 2004

> got a pop, spark, and puff of smoke from the CPU.  I think 
> it's one of the 
> little blue capactors 
> [snip] 
> Anyone have experience reviving old gear?  Mine's been boxed 
> for over a 
> decade.  Any precautions I should take before I try to power 
> up another 
> unit?

My offerings:

1) Have a generous supply of bypass caps on hand, because you WILL (do) need

2) Don't lean over the machine when applying power.  Big caps fail too.

3) Have another way to cut power quickly, in case you're not comfortable
reaching across flaming innards to get to a rear-mounted power switch.

4) Remove boards and test the power supply separately before applying power
with boards in.  You can also spot check each board for shorts while they're
out, which isn't totally deterministic since some shorts can/will occur when
power is first applied and the part dies at that moment.  With S-100 stuff
I've been using a bench supply with adjustable current limiting to power
test boards... better than throwing the weight of a chassis' high-current
supply into a shorted board.  You just get an over-current light rather than
letting the magic smoke out.  In a few cases I've also been able to find bad
parts quickly this way, just by setting the current limit low--0.5 amp or so
can warm up a shorted part enough to find it with a fingertip, but not do
any damage to the board.

5) A little eye protection never hurts, because you never know what
direction or distance those little bits are going to go.

Your experience is how two of my H-89's came to be dubbed Sparky and Smokey.
I have another called Shell. ;-)


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