channels 1 and 2 do not work on my roadster

[label thief]

i thought it might have been a g system problem. but i unhooked the g system and it appears only channels 3 and 4 work on my mesa roadster head. what could the problems be that only 2 channels work? bad tube?

 

[Anonymous]

i thought it might have been a g system problem. but i unhooked the g system and it appears only channels 3 and 4 work on my mesa roadster head. what could the problems be that only 2 channels work? bad tube?

Get a preamp tube known to be good. Swap it out with each of the positions in the preamp, trying out channel 1 or 2 after each swap. If you have no luck, you may have a big issue, but most likely this will fix it.

 

[domct203]

Get a preamp tube known to be good. Swap it out with each of the positions in the preamp, trying out channel 1 or 2 after each swap. If you have no luck, you may have a big issue, but most likely this will fix it.

+1

Check V2 first. That tube is the third gain stage for ch's 1 & 2 on one side ( V2A ) and 3 & 4 on the other ( V2B ).
It's possible that you lost one-half of the tube ( V2A ).

Dom