Had practice yesterday and my amp was making some crazy noises. At first thought it was the flourecent lights turned the light switch off back on amp sounds normal. Hour into practice it comes back put the amp in standy by turn lights off back on flip the standy switch poof one of my power tubes blew. Fuse is intact tried with another tube when I got home and checked the tube socket looks good bad tube has some black burned stuff on the back side of it. New tube lights up. Think all is good just replace the power tubes ?
Power tube Problem
- Thread starter schmasty
- Start date
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I'm assuming the amp is a Rectifier.
The "black stuff" could be carbon and you need to make sure that there is not any in the tube socket that could short across the socket contacts.
Also, you should have the amp checked by a tech that the screen grid resistor(s) did not blow. The fact that the tube "lights up" simply means that the heater is working. If the screen grid resistor did fail (a common thing with a tube failure like this) that tube is pretty much turned off, and your output section is unbalanced.
If the amp is under warranty and this was a Mesa tube the repair should be covered.
Good Luck,
Dom
The "black stuff" could be carbon and you need to make sure that there is not any in the tube socket that could short across the socket contacts.
Also, you should have the amp checked by a tech that the screen grid resistor(s) did not blow. The fact that the tube "lights up" simply means that the heater is working. If the screen grid resistor did fail (a common thing with a tube failure like this) that tube is pretty much turned off, and your output section is unbalanced.
If the amp is under warranty and this was a Mesa tube the repair should be covered.
Good Luck,
Dom
Not always, and not when I had a powertube failure in my Roadster.
http://forum.grailtone.com/viewtopic.php?f=24&t=32394
Dom
http://forum.grailtone.com/viewtopic.php?f=24&t=32394
Dom
elvis
Well-known member
The fuse protects against dead shorts. It is a slo-blo, so it will allow some power through to charge the filter caps. Between that and the power stored in the caps once the amp is on, a lot of damage can occur without blowing the fuse.
Guys thanks for the help. I took the advice had the amp checked out by a Mesa service Tech. 1 power tube blown ( I knew that ) and V2 Pre amp tube. Grid resistors checked out and amp was given the complete check up. Switches and sockets cleaned also. Happy to have it back 
Glad it all worked out!
Dom
Dom
