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Good point! I wasn't clear enough. The failed components need to be pinpointed. I didn't mean caps can just be replaced in the hope of getting things better.
The problems are indeed more common in switching mode supplies and especially after 2000. And it's true, old analogue synths are not the usual victims. It is possible to have a cap dead without visible damage, but as Gordon said, blind part replacement is not the way to go.
Sami Jumppanen
http://netti.nic.fi/~some-e
- SGS2 -
On Tue, Mar 11, 2014 at 11:42:21PM +0200, Sami Jumppanen wrote:
> After fixing a number of devices by replacing capacitors only, I recommend
> you always begin with them if it's likely a power issue. Electrolytes, no
> other types. Medium sized, not the smallest or biggest (depending on the
> device, there may not be large capacitors). By the numbers: usually 470 to
> 2200 micro F and from 15 to 63 volts.
... and I generally recommend people scrap equipment that's been subjected to "re-capping" when they bring it round for me to resurrect.
I've pretty much only ever seen electrolytics fail in cheap crappy switched-mode power supplies (think Amstrad satellite receivers from the 80s and 90s). Of the rest, I've replaced maybe half a dozen electrolytics that were actually the cause of a fault and only one of them in an analogue synth.
Electrolytic capacitors just don't fail that often.
DO NOT just start ripping them out because you suspect there's some sort of fault. You'll only make matters worse.
--
Gordonjcp MM0YEQ