Blown JBL PX300.4 Amplifier?

Ok, so I pulled all 8.  The only one that seems like it has a short was the one that fried.  There is full continuity on all 3 legs with one probe on the backing plate.  The other 7, with one probe on the backing plate the left and right legs read 1 - as in no connection (not 001), and the middle reads 001.

But like you said if I'm going to replace them all - is it really even relevant?

Ok, well Its 2:47 am - so I'm going to go to bed for the night.  Will try in the morning.  Have a few questions though.  Considering all the mosfets are out - can I still do the test you said? 

Also I'm not sure exactly what you are looking for - you mention we need to check the resistance of the amp and then mention voltage.  Do you want to measure the voltage drop after the resistor? or do you want Ohms or...what?  Essentially do you want me to check the resistance, or the DCV? 

Thank you so much for your help!

Have a good night!

I did not see any thickness specs on your Kapton tape.  The adhesive hampers it's ability to transfer heat.  You really need to remove the adhesive from the tape before inserting on the heat sink.  Acetone works great, in a metal parts bowl or pie pan, pour a small amount of acetone into pan, set a few inches of the tape into the acetone, let it sit for a minute or so.  Acetone is extremely flammable.  Remove it from the acetone and rub the adhesive off with your finger.  You will be able to tell when that section is clean.  Do the same to another few inches until the entire piece is free of adhesive. 

Cut the tape a few inches longer than you need it.  You can wrap it around the heat sink and using scotch tape, tape it to the outside of the heat sink to hold it in place.

Those will work.  The only thing we need to check the value of the resistors.  If they are below 47 ohms you may want to change them.