Audison SRX5.1 in protection.

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Hi all, just trouble shooting this amp and it goes straight into protection, all outputs appear to be fine, the PS is using 75333p mosfets and one of them wasn't seated correctly on the heat sink when I initially stripped the amp down, someone else had already been in here and not done a too great a job! strangely all the PS fets also appear to be OK, I removed the suspicious fet but amp still goes into protect, gate resisters are 10ohms and seam fine.

..so where do I go from here? shall I pull the rectifiers to isolate the output section?

Mark.
 
OK, I removed the rectifiers and the amp powers up fine, I think the sub section is where the problem is, the small drivers look a bit tired and also have small deposits of green stuff on them.. the problem is they are so small determining what value/type they are is a nightmare!

Mark.
 
fitted rectifiers back in then pulled the smd driver on the suspect sub woofer output, the amp now powers up OK and the front and rear channels work fine now :)

so now I have to figure out the subwoofer channel and having a hard time identifying the smd driver I need, the markings are long gone! I really need a schematic but this would seam impossible to get hold of.. the front and rear outputs use different devices so I can't go by those ones.

any ideas?
 
sorry about the poor resolution, must of had camera on lowest setting, doh! on the left you can see the green deposits I was talking about earlier.. you can see the basic layout of the amp and how the front/rear outputs differ from the sub outputs, at this point the actual outputs all seam fine :)

DSCN4774.jpg

DSCN4772.jpg
 
If they're connected the same and the components connected to them are the same, it's probably safe to assume that the unknown component is the same as the others.

A pair of cheap ($15-20US) reading glasses (I use +2.25 diopter) make a huge difference. Even with glasses, I have to use a lighted magnifying glass to see some of the markings.
 
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