Help me fix MTX 152 and MTX 500D

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Generally, when the regulators fail, they destroy most of the op-amps. Sometimes, the damaged op-amps can load the regulators and cause them to fail. Repairing the regulators is generally only about 1/4 of the work to get the amp back running.

With the amp powered up, you need to measure the voltage on the op-amps to confirm that the regulators are producing ±18v. If so, you would then need to find what's loading the regulators.

Many times, the defective op-amps will run much hotter than normal. Rarely, an op-amp will become a dead short and won't allow the regulators to produce any voltage. Those can be more difficult to find because they don't run hot.

Are the resistors you used 1/2w or larger?
 
The replacement that digikey superceded the ssp45n20a fet drivers is wrong and I had to put back the original ones, and replaced again those Q transistors and now it all works fine. So the 500D is done. My other 500D that I fixed before has some major capacitor leaking, the whole board is wet. Whats going on

What would be a good replacement for SSP45N20A?
 
I got it put together the best I can and it powerd up and I can hear the speakers but barely, with gain all the way up as well as the gain on the player all the way up I can barely get it to produce sound. I guess I did not put the correct resistors where they should be. I will have to wait until I get one good 152 then see what resistors they are. Or I can use this for parts.
 
because the burned resistors burned the labeling on the board so I don't know which ones they are. So the best thing I can do is to wait until I find another 152 or if someone can post hi-def photo of the good board. I replaced the op amps, socketed the board so thats no problem. Am glad that I fixed the other amps.
 
I want to fix it but wuthout proper information I hate to guess what goes there, so until I get proper picture of this amp I might be able to fix it. other chanell is not grouped the same, resistors are totaly at different positions and not grouped the same. So I will wait until I get proper information on the amp and go from there.
 
Perry, I found another MTX 152 that works now I can see what components are there to fix my other MTX 152. However this amps has problems too, it works fine at low gain, soon as you turn the volume up or gain on the amp up, the output distorts badly, it sends nasty noise to speakers. What could it be? op-amps.? On the board I can't see anything that is overheated, it looks ok.
 
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