This monstrosity of a Fender Bassbreaker 18/30 amp has been brought to me for repair..usually I wouldn't touch this type of amp with a 40 foot pole but it belongs to a friend. Channel 2 ( the 18 watt channel ) is insanely loud with the volume on 2 but channel 1 has no sound at all unless I hit the guitar strings really hard..then it gives a weak farting sound. The channel switching ,either by the front panel switch or the footswitch, appears to be working fine. Fender have been spectacularly useless in not even responding to my request for a schematic. I have removed the preamp board and resoldered every joint and reseated all connectors and tried new tubes but the fault remains. I had to replace the volume pot and bass pot as in getting the really tight knobs off the pot shafts came out of the pots...talk about cheap and nasty ! So has anyone dealt with this problem on this model before ? or has anyone managed to get hold of a schematic for it ?. Stay safe.