Thanks much, I'll post some results-

So you think the main power amp chip might be the culprit and not peripherals? If i was to pull the main power amp chip would I look for shorts across various terminals? It says TDA 7273 on it- could that be the correct name? I'm gonna try to power it up with the plug to the main board from the power chip disconnected and see if it still blows fuse. any help appreciated- thanks

The diamond shape is a bridge rectifier which comes as a single component. It is made up of diodes internally though, hence the appearance.

I have the same problem, same amp- it smoked a bit and blew the main fuse 6.3 amp, I bought a new fuse and it blew immed. assume its something in the output line- found a schematic and know a bit of electronics but not enuf to get started... any help appreciated, prob not worth much paid tech time as these amps are only about $150 bucks used?