18 Jan
2012
18 Jan
'12
9:44 p.m.
Ian King wrote:
Instead of all of that, why not just replace the
capacitors?
Why not just verify that the capacitors meet specifications, and only
replace them if they've failed?
Anyhow, even if the capacitors are replaced, I'll *still* want to
monitor the voltage and ripple.
even when they're sitting on a shelf aluminum
electrolytic capacitors
(AlECs) degrade with time.
There is very little non-reversible degradation. Most of the
degradation is oxide breakdown, and is reversed by the reformation process.
Note that the reformation process isn't doing something bizarre to the
capacitor. It's basically doing the same thing the vendor does to it
during manufacturing to grow the oxide layer in the first place.
On our PDP-7, we elected not to replace the filter
capacitors, which
are the size of large soup cans.
Have you looked at the capacitors in the "capacitor box" of the ECL
power supply of the KL10, between the H760 raw supply and H761 regulated
supply? There are 13 300,000uF 15V capacitors. There are certainly
modern replacements that are smaller, but if they're not broken, I'm not
going to replace them. They're also fairly expensive, roughly $50 each.