Help with a damaged PPI A600.2

[punchpeanut]

Hi all. I recently got my hands on a PPI A600.2 amp that is having some trouble. This is the quote from the previous owner.

"I was using it as a sub amp. At the time it quit it was pushing 2 15" SoloBarics, 8ohm drivers in a parallel bridge. The bass all of a sudden got very quiet and I heard distortion though my highs. I pulled the fuse on the amp and the distortion went away. It never blew a fuse on me in 4 years. When the amp turns on it is always in protect mode now, both LED's are on."

I was wondering if anyone had any ideas on where to start looking. If anyone has seen this before on this amp or any others, how was it fixed? Thanks so much.

[offroadbum]

open it up and look to see if any of the trnsistors have gotten loose.
this amps don`t have alot of problems....

[punchpeanut]

I took off the bottom plate and as far as I could tell, all the transistors (or fets) looked good. I have seen amps where 1 of the leads were melted before. I will take some pics of the internals to see if anyone can spot anything funny. I may have to send it out to a shop .

[punchpeanut]

I think I spotted the problem. Do you guys think this will be an easy fix? Those resistors look pretty big, are they 1/2 watt? I also noticed the design uses lm833 op amps, would it be worth trying ops2134's or similar? I can't spot any other problems, but I think this is it. What do you all think?

[EnvisionAudio]

If you know what you're doing. I can't recall those resistors' exact function, but you need to find out why they are burnt. Replacing them will only further damage the CAUSE of the overload.

I know you're stuck on fixing it yourself, but I recall your email to me and I suggested finding a competent repair tech and saving the headache.

No, stick with the LM833, they're fine in your app.

[punchpeanut]

Yep in the end I might just send it out to a shop to get it fixed. What I was thinking is that maybe it was just a moisture issue. Look at the 2 RCA jacks, the right one has a foam boot around it to seal it off. It's missing on the left one. I thought maybe some liquid got in and shorted the 2 resistors out, maybe a wire strand or something else too. I might pull the board and see if there are any obvious problems on the back.

[TO-3]

Those are 10 ohm/3W resistors. They only burn out when the PS is not properly grounded. Replace those and you'll be set. Cheers

[punchpeanut]

Sweet. Thanks a lot. I was going to send the amp out to a repair shop this week. They have a flat repair cost of $80 plus $12 return shipping. Replacing 2 resistors will be a lot cheaper!

I'll try swapping them out as soon as I can dig up the resistors and let everyone know how it works out.

Thanks again.