18 Jan
2009
18 Jan
'09
1:35 p.m.
On Sun, 2009-01-18 at 17:49 +0000, Tony Duell wrote:
I repair a lot of synthesizers, some of which have truly horrible linear
power supplies which are terribly undercooled. Lots of people bang on
about how the capacitors only last 15 years and become dried out from
the heat and need replaced. Well, I've changed one electrolytic cap,
dozens of rectifiers (bridges and diodes), and resoldered hundreds of
dry joints. Caps are the last thing I look at. Plus, if a power supply
cap is on the way out, you'll get audible hum which is a dead giveaway.
Gordon
Industry folks say that the lifetime of electrolytic capacitors is
about fourteen years. Since the filter caps in our machines were
significantly (i.e. TWICE) older than that (and some showed physical
Odd... I run machines considerably older than a VAX-11 and have not had
to replace that many electrolytic caps. Yes, I've had the odd one fail,
but by no means all of them. I think I've replaced a couple in HP
desktop calculators and none at all in the PDP11s and the PDP8/e