Tubes Won't Light on Classic 50/50

Dennis Detweiler · Post by **Dennis Detweiler** » 13 Jun 2003 8:50 pm

This amp has been working great until I turned it on tonight. The power light, standby lights and fan are functioning. All of the fuses seem to be intact. So why no power to the speakers?
Thanks
Dennis

John Bresler R.I.P. · Post by **John Bresler R.I.P.** » 14 Jun 2003 8:06 am

Dennis:

I have no experience with this amp, but since you stated that the tubes don't light up, it could be a filament problem. If you have a schenatic of the amp and a volt-ohm meter, you could check the filaments of each tube to see if there is continuity. This is assuming the tubes are wired in series. A good tube manual will also provide you with the pins numbers fo the filaments.

Jerry Erickson · Post by **Jerry Erickson** » 14 Jun 2003 1:35 pm

Pins 4&5 are the heaters on an EL84.

Dennis Detweiler · Post by **Dennis Detweiler** » 14 Jun 2003 6:08 pm

Problem solved. There are 4 fuses on the circuit board. I overlooked the 10amp fuse. Not sure what part of the circuitry this fuse protects?
Thanks
Dennis

John Bresler R.I.P. · Post by **John Bresler R.I.P.** » 14 Jun 2003 6:31 pm

Dennis:

You could always ask Mike Brown about the fuse. He's always been great at customer support.

JB