When I was a kid I made the stupid mistake of plugging my crate Gaza head out to the guitar input of my peavey studio pro and the crate stopped working. An amp tech fixed it and said the transistors had blown. Well weeks later the peavey stoped working with this loud buzz hum sound. Using it properly of course. Since then I'm 37 years old now and have learned a bit since then. So I have pulled my peavey out of the attic and am ready to repair it myself if possible. The hum is constant, so I shut it off and pulled speaker wires and measurements show 5volts dc to speaker. So I have pulled chassis and gave it a look and see the mje0800 and mje700 and according to the data sheet I believe it said the output should be 5volts dc but I am not sure how to test them. I do know that when I hit them with temp Gun they were very hot, and the sand block resistors got hot. I am changing the transistors and the four diodes that pass through the heatsink. How can I check the transistors if possible? And thanks for adding me on the network I am very happy to be a part of it. I would like to add some pictures to show the work area but am not sure how to add attachments.