Like the previous time quoted below, thought it was a PbF problem at the input socket, as a definite problem in that area causing about 1/10th volume but not mains noise intrusion, when testing on receipt PbF solder used inside but nowhere stated , as per usual. The same symptoms appeared before and as used with a footpedal at that point, under warranty Fender replaced the foot pedal. Is the schematic for this digital+valve amp around ? I cannot see how loss of ground contact and ring contact to ground would cause a consistent (in failure) 1/10 or so volume drop. PbF solder points at the socket (now managed to remove the preA pcb ) look good (for PbF) No WD40 this time, input socket bush nut , not loose on receipt, same off centre type , not desoldered yet but probably another junk Neutrik. The 2 parts of the barrel turn relative to one another ,easily , without the bush nut in place braced against the chassis
previous experience " Fender Bassman 250 , PR597, 2005 Bad input socket, is there a generic problem with these? Of course I thought it was a PbF problem but it escaped that , leaded solder inside. Solder joints seem fine and no broken tag. Socket make not seen , not desoldered yet, maybe make underneath. The jack centre line is off-centre of the socket centre line , the sleeve contact is a barrel which is chromed and only makes contact with the now tarnished ground contact if the metal bush nut is tight and the 4 pointed grounding tangs are not bent and are making good contact with chassis metal. So 2 ways of loosing ground contact. With no bush nut the chromed barrel will rotate a few degrees and then just touching contact to the socket ground terminal . Of course I have the preamp out of the chassis now and so do not know what the initial state was other than the bush nut was not loose when received. All compounded by gallons of WD40 squirted everywhere that has certainly lost the tip and ring bypass contacts to ground with no jack inserted. I can see repeated tightening/ overtightening? of the metal bush nut plenty of spanner/wrench force can be applied as metal nut and metal bush) will deform the 4 tangs/ dig deeper pits into the front panel metal, until eventually no contact. I expected some no-name Chinese make but no , it is Neutrik with this crappy design.