I have two Marantz Model 2 Amps hooked up to a Fairchild 245 Preamp. Recently, the main fuse on one of the Model 2's blew for no apparent reason. Needless to say, changing the fuse didn't help. It will blow after the amp has been warming up for about 30 seconds. Anyone know the most common causes for this?
Probably power supply problems, likely a bias resistor or a capacitor; could be both, one taking out the other. How long have you had these units and when was the last time you had them in for service or maintenance?