PDP 11 gear finally moved

tony duell ard at p850ug1.demon.co.uk
Fri Jul 17 13:56:26 CDT 2015

> Perhaps.  But not all of it, certainly.  I'm currently four for four
> fixing dead flatscreens by re-capping their power supplies; I imagine
> others have similar experiences.  It's not a huge stretch to imagine

This could be taken to show that modern capacitors are not reliable, and given
that there are plenty of 40-year-old ones still in use in various classic computers here
it would be better to leave them as-is

More seriously, a lot of modern consumer stuff seems to have marginally-rated capacitors
(and the use of 85 degree ones doesn't help). Possibly on those it is a good idea to 
replace them. But the ones in PDP11s were good quality at the start and were over-spec'd
in general. 

> that other power supplies may have similar issues; even if it turns out
> to not be the case, there is probably at least a little "can't hurt
> anything, right?" running around.

Ah but it can hurt. Damage to the PCB (unlikely, sure), the new part might be faulty
and thus introduce more faults, you might make an error fitting it, and so on. I prefer
to only replace that which needs replacing.


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