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In Reply to: RE: The fallacy of "reforming" capacitors posted by Sherwood Forest on December 21, 2015 at 14:00:31
Whether or not "reforming" is legitimate or not, can (and has been) debated.
What is NOT debatable, is the damage that can be done to the amp if the "reforming" doesn't work and the caps have catastrophic failure.
I have never heard of anyone having to raid their 401k in order to recap their amplifier - It ain't a deal ($$$$) breaker. You can attempt to reform the caps in your amp and it may or may not work, or you can just buy new parts and be assured it WILL work.......
I vote for doing it right the first time.
Meat; It's the right thing to do. Romans 14:2
Follow Ups:
"Whether or not "reforming" is legitimate or not, can (and has been) debated."
But once again let me say there is NO DOUBT that re-forming of an electrolytic cap is a legitimate process, and is recognized as such by the major capacitor makers.
But reforming is not magic! It does not restore a cap to proper performance in every case - some are just too far gone. And it can be done improperly and that can be trouble. There is a way to determine if the reforming process has been successful, and there is also a need to physically examine the cap, checking for warm/hot spots during reformation.
I've personally applied my reforming process to 100s of caps, and I'd say about 80% were successfully reformed. The 20% that were rejected were tossed either due to high DC current flow through the cap even after the proper reforming process was done; or I felt hot spots on the cap during the reforming process. A few vented on their own or started to distort the case.
That DC current thing is important. It's heat build up inside that causes those "exploding cans". The heat is a result of current flow through the cap. For instance, a cap exposed to 400 volts that has 1 ma of leakage has to dissipate .001 x 400, or 0.4 watts. At 10 ma leakage it becomes 4 watts and that is a significant amount of heat - more current flow = more heat. It could cause a cap to vent to relieve the internal pressure. And yes, I am ignoring the impact of the ripple the cap sees to keep this simple.
The caps I've successfully reformed show DC current leakage at a fraction of 1 ma. - usually under .25 ma. at 10% over maximum rated voltage on the cap.
!
The Mind has No Firewall~ U.S. Army War College.
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