Gigaworks S750 7.1 crackling and cutting out on ONE channel

[manywelps]

I'm about to crack this beast open, and was wondering what parts I should be suspecting that would cause crackling and cut-out on the front right channel only.

Bonus, it happens even when headphones are plugged in and the relay has shut off the main amp by relay (so it could be an opamp or something small).

[manywelps]

Re: Gigaworks S750 7.1 crackling and cutting out on ONE channel

Bad Caps: http://i.imgur.com/QYlLo.jpg

do I just replace the bad ones or all of them?

Also any caps that people recommend?

(the 2 closest to the camera are very bulged, the 2 further away appear fine).

Most importantly: would this create cut on in ONLY ONE channel?

[momaka]

Re: Gigaworks S750 7.1 crackling and cutting out on ONE channel

do I just replace the bad ones or all of them?
Also any caps that people recommend?

If 2 have failed, the other 2 are likely on the edge as well but not just showing it yet. Therefore replace all of them. CapXon has a bad reputation on these forums, so it's a good idea anyways.

Before replacing them, however, I do have a question - what circuit are these caps part of? Are they just filtering the line voltage on the primary side of the PSU? And if so, is there a PFC circuit? (If you're not sure, post some pictures.)
Reason I'm asking is because it is usually rare for high voltage caps to fail, even from inferior brands.

As for replacements, just match the capacitance (uF) and voltage (V) ratings (these are high voltage caps so you don't need to worry about ESR). You can go higher with the voltage rating if you like (next common standard rating is 250V). Also, make sure the replacement caps will fit on your board and that they are rated for 105C.

If you're in the USA, digikey.com and mouser.com are good places to buy the replacements.

Most importantly: would this create cut on in ONLY ONE channel?

It's possible. Depends on what those bulged caps do in the circuit.

If you have more CapXon caps in the PSU, now would be a good time to replace those as well (might as well since you're already paying for the shipping with the big caps. Besides, the small low-voltage caps are cheap anyways). The ones on the secondary side of the PSU should be low ESR, though, so for those, also post the series (usually 2 or 3 letters written on the caps, like "KM", "KF", etc.).

[mariushm]

Re: Gigaworks S750 7.1 crackling and cutting out on ONE channel

momaka, he posted more pictures about this amplifier here:

https://www.badcaps.net/forum/showthread.php?t=18136

Based on the pictures there, it looks to me more like bad soldering and loosened screws.