FuseG4
Our Neighbor Totoro
my amp was acting a little funny. one 6v6 was red plating barely and it was biasing hotter than the other tube by a good 4 ma. and I immediately thought back to when I blew a screen grid resistor a while ago. I had replaced one a while ago and so I went back into the amp to see if it looked OK and reheat the solder joints.
i then remembered that at the time I had bought 2 resistors and had not replaced the other one but had briefly inspected it for damage when its partner got fried. low and behold the remaining stock one had some enamel chipping off the outside and a faint burn mark there. so I go swap it out.
this new resistor at r63 went in fine but in reheating the joints on it's mate at r62 some little tiny metal ring thing fell off the pcb :/ dammit. so I had to run a short lead from leg of the resistor to the point that the pcb trace used to be connected to.
then when I powered her up the bias would not adjust via the pot, and hung at about 6 ma. I reheated the solder joints on the bias pot. Finally it works.
The amp sounds pretty sweet for now but I'm worried about that pcb trace. If my wire I installed fails it's gonna take out that power tube pretty soon right? I mean, that's the ground for the screen grid resistor, I think.
also, my footswitch has stopped working. when it's plugged in the trem is on all the time and the reverb is off but stepping on the switch makes sometimes audible POPs through the speaker. Bad footswitch or something?
i then remembered that at the time I had bought 2 resistors and had not replaced the other one but had briefly inspected it for damage when its partner got fried. low and behold the remaining stock one had some enamel chipping off the outside and a faint burn mark there. so I go swap it out.
this new resistor at r63 went in fine but in reheating the joints on it's mate at r62 some little tiny metal ring thing fell off the pcb :/ dammit. so I had to run a short lead from leg of the resistor to the point that the pcb trace used to be connected to.
then when I powered her up the bias would not adjust via the pot, and hung at about 6 ma. I reheated the solder joints on the bias pot. Finally it works.
The amp sounds pretty sweet for now but I'm worried about that pcb trace. If my wire I installed fails it's gonna take out that power tube pretty soon right? I mean, that's the ground for the screen grid resistor, I think.
also, my footswitch has stopped working. when it's plugged in the trem is on all the time and the reverb is off but stepping on the switch makes sometimes audible POPs through the speaker. Bad footswitch or something?
