Sony STR D865 5.1 channel receiver blows the 6.3 Amp 125 Volts fuses that send power to the MN2488 & MP1620. Tested with an ohm meter and there is zero resistance between the collector and emitter on both transistor. MN2488 IS Q753 & MP1620 IS Q754. The two transistors are located to the right side of the main board if you are looking at it from where the power transformer is located. My experience has been, when you replace transistors of the output of just about any amp, there are still components that can damage the new parts. Some leaky parts some will eventually burn out the outputs. My question is, If you have experience with this exact model, and you have replaced drivers, and associated parts around the output and drivers, I no longer have my in-circuit Crickett Tester which also measures gain, etc. I do have a capacitor tester that is really good in-circuit tester which applies a 100 Khz signal to the cap and is very reliable. But if there are IC's that need to be looked at, I am not sure if they could have been the cause of the problem. The receiver wires and speakers have all been looked at and tested. Speakers & wires very well with another receiver of the same ohms. If anyone can offer some suggestions, I would gratefully appreciate it very much. Peterjb1