The amp has dual power channels rated at 75W each by the makers and uses a pair of TDA7293s - with 15 leads to remove from a double sided PCB with some very fine traces, replacement is tedious to say the least.
There is a quite a decent looking heatsink and the TDAs are clamped with steel brackets that apply lotsa force to hold the packages against silicone thermal pads which are stuck onto the heatsink.
When re-assembled and tested, each channel delivered 90W clean into an 8 ohm load - which is rather a LOT for an IC that only has slightly more heat tab area than a *single* TO3P !!
A finger test revealed that each TDA was getting very hot after only a few seconds while the heatsink was still essentially at room temp. Tested with a K type thermocouple, the mounting tab reached 90C in just over 1 minute and would clearly soon exceed 100C as the heatsink warmed. This is not good.
Being suspicious of the stick-on thermal pads, I decided to remove them and fit mica ones instead, aided by silicone grease. ( Pealing off the original pads revealed a thick film of adhesive on the heatsink which had to be scraped off and rubbed clean with solvent).
When re-assembled, I tested again and it was a very different story. The temp reading on the mounting tabs reached only 56C in the first two minutes and then stabilised at just under 60C.
Is there any need to mention the amp was made in China ??
BTW:
The reason for the dual channel failure is almost certainly that the owner plugged both outputs into the same speaker cab.
... Phil