4, Problems: blue sparks coming from circuit

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Al.m2008-06-03 16:21

I have model 4 panels with model X servo amps but the amps are not working well. There are blue electric charges coming from the circuit board capacitor ends where they meet the board near the tubes and a sizzling type sound. Panel sound is very weak as well when music is played. Any possble ideas on what might be obvious solutions? Thanks

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Ken Ealey2008-11-08 04:58

Al, I\'m surprised nobody has answered given your post time, so I\'ll try helping. I assume you know that the blue sparking is the high voltage seeking a conductive path, and that when you see arcing, you\'re actually looking at current - just like a spark plug. For the path on the board to be conductive, it\'s safe to say that it is not clean. Rather, contamination is present, such as oil that has leaked from the oil-filled .1uf output cap. Oil itself is a great insulator of sorts (and is why oil caps have it), but oil draws air-borne contaminants, which in turn attract moisture. This mixture can be a good conductor and if enough accumulates, then we have the sparking that you\'re seeing. So, a possible solution would be to clean the board with something like denatured alcohol (mostly ethyl alcohol), and also inspect all high voltage parts, in particular the oil caps themselves for pinhole leaks. Just normal handling can tell you alot since anything will likely get on your hands. Also, the cap might have a sizeable air bubble inside that indicates some oil has escaped - although some perfectly good caps can have these as well. The last pair of servos I rebuilt were for a customer that had an oil leakage problem develop out of his main HV p.s. caps and pretty much took out the supply by the means mentioned above. It all could have been avoided had the amps been properly maintained, as they had been serviced prior to my looking at it but with no action taken. I would advise taking care of the problem first before continuing to operate them, even though music does come out. The weak level is probably due to this problem, or may be a separate one altogether. You mention both amps are not working well, which I find interesting that both chose to have problems at the same time. Perhaps you meant just one amp was having trouble. Also, just make sure you have good tubes and a clean mounting for them, with no carbon (burnt) buildup. Hope this belated answer helps. It\'s all I can think of given what you mention. Ken Ealey

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