Goldtone gone south...

[DanD]

It powers up to standby, filaments on.
Switch to play and the AC line fuse blows.
Any Guesses,

DanD

[plexi67]

pull the output tubes, put in a new fuse, then see if it will stay on when you flip the switch off standby. if it stays on,most likely you have a bad output tube. if it blows with the power tubes out. then you have other problems.. rectifier or bad cap or transformer. These amps are also know to have power transformer problems. I think mojo sells replacements for them.

[ChickenLover]

FWIW, Don't know your exact model but here's a schemo I made of my Gibson GA15 (15W, 1x10", no reverb) years ago showing the C#/R# designations. Use that handrawn schematic that's been floating the web for years for the values. Some values were incorrect in my amp (noted on this schemo) and a few were missing.

Also, I did not show the PI plate suppressor cap in this schemo. I think it's C29 but in any case it's hard to miss...it's right next to the heater connector for V2. There are also spots for C9/C10 (IIRC) for V1a and V1b...these would be for suppressor caps but are not used...and the socket covers up the holes on the underside of the board so forget about using them.

Bear in mind that these amps are set-up to dissipate like...17 friggin watts per tube at idle. Plate voltage is too high in these imo. A 180ohm cathode resistor puts mine right at about 12.5W plate dissipation and about 2W screen grid dissipation per tube.

http://i108.photobucket.com/albums/n4/mtbucket_2006/VelocetteSchemo.jpg

[DanD]

Turns out it was one of the el84's.
Put a set of JJ's in and the amp works fine, sounds incredible.

Thanks again guys,

DanD