23 Feb
2009
23 Feb
'09
9:27 a.m.
js at cimmeri.com wrote:
On Feb 22, 2009, at 3:33 PM, Gordon JC Pearce wrote:
Gordon, you don't mention how many caps you've looked at or tested, or
how you've done so, but I encounter them constantly. Not so much in
the 1980's vintage DEC equipment YET, but it's no myth that AEC's are
electrochemical vats that have a lifespan. The lifespan varies widely
depending on many factors, heat being the big one.
jS
Hundreds, possibly thousands, over a period of about 20-odd years. Most
of them have been exposed to the heat and vibration of electronic music
equipment power supplies. I've never seen one even start to dry out.
What I have seen is hundreds of failed power supply diodes, that may
eventually stress a cap until it fails. Even then I've never seen the
actual cap go. I just change them on the basis that I don't want a
repair to bounce.
I keep a stock of 4A 1000V diodes, and a stock of LM723 voltage
regulators (amazingly common in old synths). Smoothing caps, maybe a
couple.
Gordon
I have to say, for all the talk of failing caps
in power supplies
I've only ever seen one electrolytic cap fail *ever*, and that was
last week in a one-year-old graphics card that has hardly ever been
powered off...