Amateur electronics questions, but almost on-topic

[Tom Peters]

At 02:14 PM 3/5/2005 -0500, you wrote:
>(1) there has been much discussion in this list about capacitors failing. I
>recently had a cap on a QIC-24 drive fail with a bit of sound and fury (axial
>tantalum). Is there any way to test for this other than desoldering every cap
>(at least every electrolytic) and testing it on a cap meter? I don't want to
>fry my IMSAI, but there are a lot of caps in there and it would take 
>forever...

Failed shorted I guess.  You can ohm-meter the remaining caps- 
Electrolyltics should show a varying resistance over time as the battery in 
the ohmmeter charges the cap. Don't try this on a BIG cap. If it shows a 
really low resistance that doesn't change, that might be a RBT (really bad 
thing).

>(2) (flame risk) My Tek 555 popped and blew a fuse when I had it plugged in
>last. I disassembled the PS and cleaned off the dust, and I want to test 
>it by
>itself, but the power-on relay won't close. Any hints, or is this like
>amplifiers where the tubes need a load?

Switching power supplies need a load. A Big linear may not. There's 
probably some sort of interlock somewhere.



[Philosophy] "For a successful technology, reality must take
precedence over public relations, for Nature cannot be fooled." --R.
P. Feynman
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