Just got a FJA modded Single Recto - having issues

[metalhead120]

Everytime I turn it on the main fuse pops. Don't know what's going on. What do y'all think? Please help!!!!

Eric

 

[UnderJollyRoger]

Power or Standby ?

Could be a tube ... I think there was a thread a while ago (or maybe I've read it somewhere else) where someone suggested pulling the tubes and then turning it on. Not sure about this, though ...

 

[domct203]

If the fuse pops as soon as you turn on the main power (still in standby) it is probably just a bad rectifier tube. Make sure the amp is set to Solid State Diode and remove the rectifier tubes (5U4GB). If the amp powers up, there is the culprit.

If the fuse pops when coming out of standby, it is most likely a bad power tube. Pull out all the powertubes and see if the amp will come out of standby without blowing the fuse. If it does, you have a bad powertube.

... I think there was a thread a while ago (or maybe I've read it somewhere else) where someone suggested pulling the tubes and then turning it on. Not sure about this, though ...

That is correct, refer to this Mesa Troubleshooting video:
http://mesaboogie.com/news/2010/11/mesa-amplifier-tube-troubleshooting/

Dom

 

[fluff191]

Did you get it yourself from FJA? Or secondhand? If you got it from FJA, you should call or email Jerry. Extremely helpful guy.

 

[R_ADKINS80]

well the guy has a single rec so that rules out bad rectifiers tubs, as he hasn't got them.

 

[94Tremoverb]

Probably a shorted rectifier diode (solid state).

You can get close to confirming it if you remove all the tubes and power the amp up - if it still blows the fuse, it's not a tube fault and so it's a tech job anyway. Don't try this more than once, constantly stressing the power transformer by making it blow the fuse isn't good for it.