profile 800sx issues

[timothyr1014]

Okay, total newbie on a quest to learn.
I have an older (built in 1999) Profile 800sx that seems to have an issue.
Long story short, I purchased 2 of these, and they sat in boxes until last weekend...one works fine so we'll discuss the other. I am electronically inclined, and am approaching this with my usual mentality of "why pay someone else to fix it when i can learn something new". I trolled the board, and read the basic amp repair guide linked to by one of the members, and just want to make sure I am on the right track based on the symptoms.

So here goes (keep in mind, I am new at this so i compared the good amp to the bad with identical connections to minimize variables...these are the differences):

1. Upon reciving signal from the remote lead unit powers up and sends a faint whine constant on the right channel, intermittent on the left.

2. Right channel plays audio with SLIGHT degridation, left is absent unless high volume from the source is applied.

3. In all situations (including sitting idle) when the remote signal is present and the amp is on, the case/heatssink becomes very hot (ie almoost too hot to touch & again comparing to the other unit which had no noticible heat under identical conditions).

4. No blown fuse/protection/shutdown or anything.

Based on my current knowledge I am thinking something somewhere is shorting (the whine and excess heat) and was going to start testing resistence across all of the FETs (I think thats what they are sandwiched between the heatsink on the outer edge).

advce and thoughts are always welcome as its usually cheaper to listen then blow something up

TIA
Timothy

[Perry Babin]

Where does the heatsink get hot first, under the output transistors or under the power supply transistors (near the transformer)?

If it's under the outputs, does one side get hot faster than the other?

Can you post (or email) a photo of the guts?

babin_perry@yahoo.com

[davedamage]

Perry, PM me please.