In Reply to: Reforming caps posted by SteveBrown on December 27, 2003 at 14:25:44:
Here's my logic:* If the electrolytic is much over 15-20 years old, I just replace it as a matter of routine during initial restoration.
* I do this mainly because I would rather not have to hunt down a power transformer which is usually the victim of excessive current drain in the cap. In extreme cases, of course, you'll get enough of a short to blow the fuse, but the more insidious problem is too much current drawn through the power transformer, heating it up to the point where the insulation on the windings breaks down and a bigger problem occurs. Since I tend to lean towards the older stuff that's at least 30 years or older, this is my general rule.
* If you do have to establish priorities for which caps to replace, here's my general rule of thumb:
- High voltage power supply electrolytic filter caps: any one that is tied across the B+ and ground. No questions.
- Coupling caps in the audio chain that have more than 50V across them during normal operation. These are the inter-stage caps, generally and can be small value caps at times.
- Bypass caps in the power supply. Smaller value caps but have high voltages on them during operation.
- Any other electrolytic cap no matter the voltage across them.Hope that helps.
Cheers,
David
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Follow Ups
- I agree: Just replace them - doodlebug 17:34:04 12/27/03 (6)
- Re: I agree: Just replace them - microbe 22:20:34 12/27/03 (5)
- Re: I agree: Just replace them - doodlebug 20:52:20 12/28/03 (2)
- if an amp is quiet are the electrolytics in fine shape? - microbe 21:21:17 12/28/03 (1)
- Re: if an amp is quiet are the electrolytics in fine shape? - doodlebug 08:31:28 12/29/03 (0)
- I've always just replaced them as a matter of preventive maint. The few times I've ... - PureAudio 06:46:17 12/28/03 (1)
- Blown Electrolytic Story - AudCon 14:26:06 12/29/03 (0)