Jmp 2203 keeps blowing fuses

[V-Killer]

Title says it all. It's the HT fuse, replaced it and it keeps blowing. Bad tubes? OT? I'm in the Kent Ohio area. Was thinking of maybe trying the guys at guitarriot in downtown Cleveland. Any ideas guys??

 

[prsplayer86]

If you have a old but "known good" set of power tubes, Try swapping them out. Not that its always the case, but most the time your looking at the Power tubes or the OT when this pops (hehe) up.

Best of luck

 

[raiken]

If it's blowing the HT fuse, it's most likely either bad output tubes or a blown HT rectifier. Could be a transformer, but not likely.

If you don't have a spare set of output tubes to test, you can pull all four of the output tubes and put in a new fuse and see if it blows it.

If it doesn't blow the fuse with the tubes out, it is the tubes that are bad. There is also a possibility the bias diode or a cap in the bias circuit is bad, or a bad coupling capacitor, but those don't fail very often.

If it blows the fuse with the tubes out, it is the HT rectifiers or a transformer.

 

[Racerxrated]

Happened to me twice. Power tubes one time, PT the next. Good luck!

 

[raiken]

Also, if the tubes are bad, be sure to check the screen grid resistors - they will sometimes burn up with a bad tube if it draws too much screen current.

 

[glip22]

Also, if the tubes are bad, be sure to check the screen grid resistors - they will sometimes burn up with a bad tube if it draws too much screen current.

These do get brittle and sometimes the legs break off. Check the simple things first.