JSX Head Ultra and Crunch Channels don't work

[Shibumi]

I have a JSX head and the Ultra and Crunch channels stopped working. The Clean still sounds fine. Can anyone tell me if I can fix this with new tubes without taking it into a shop?

Thanks

[jb4674]

Just replace the tubes with the same type of tubes and you should be good to go. Take each tube out (one at a time) and examine it. If it doesn't look blown, then place it back. If all the tubes are ok, then it might be the preamp tubes. If you're not comfortable doing this, call a shop and find out how much they charge for diagnostics.

Jimmy

[Shibumi]

Thanks Jimmy.

[jb4674]

I forgot to mention that you should make sure the amp is unplugged (unplug the power cord from the amp itself and the wall) for a good amount of time (give it an hour just to be in the safe side), just in case.

Jimmy

[Magical Muffin]

And wear plastic gloves or something, because you don't want hand grease all over your precious hot glass tubes.

[shogun]

sounds like preamp tubes to me.. look in the manual and determine which are used by both channels.. swap until you fix the problem!

[Shibumi]

Thanks everyone...Got it all together including the beverage!