I have a Polk RM6000 Home Theater system with a powered sub. One day I turned it on and the woofer was crackling as if were blown. I have blown lots of speakers in my lifetime, but this just couldn't be on this sub though. I live in a small apartment and never ever go any where near it's limit. I hooked up another woofer and it still crackled. I pulled the amp from the enclosure and started looking at it, AH HA!! There are 2 electrolitic caps that are in the power supply section. One of them had a raised top and the other was just starting to bulge. For those of you that don't know "This is bad". But actually it's good because for $3 I replaced the caps and it is now working fine! Notice the QC Passed sticker on the bad cap. This type of repair could be in many other electroncs, esp older units. If you have problems with dim lights or displays check your caps. They dry out and are not expensive. I hope this helps someone. dorf dude...
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