Peavey XR600B (400BH)

[Wendell]

When I power up my amp the main fuse (8 Amp) on the back will blow. When I unplug the right half of the Output board the fuse will not blow. The transistors appear OK (they measure the same as the left half of the board).

Any suggestions?

[guitician]

You will need to use fundamental troubleshooting then. Look for shorts, capacitor shorts, DC present where it shouldn't be, Etc. Since the fuse blew something changed, and that something is causing the excessive current draw.

[Enzo]

They measure the same maybe, but do they meaasure right? Both sides could be shorted, and unplugging one side relieves the amp.

Go down the row of power transistors. Measure resistance from the case of each one to the two pins coming out its bottom. You should find neither one shorted. If you find 1 ohm or something - it is shorted.