Kustom Defender 112 DC Filaments

[stereomonostereo]

Hey guys,

I'm working on a Kustom Defender 112. It came in with two burst capacitors, C46 and C47, which are part of the DC filament circuit for the preamp. I've had a few others in the past that did this, and replacing the caps always brought them back. On this one however, I'm still not getting my filaments back. I'm getting my -28vdc between R127 and C73, and -11vdc between R80 and C47. My rectifier diodes are good. Anyone have any ideas of what I could be missing?

[52 Bill]

Is L1 showing continuity? Are there any broken pc traces? Are the tubes all good?

[stereomonostereo]

I'm getting continuity and the tubes are good. Might be a broken PCB trace somewhere.

[Enzo]

Take the tubes out, their low heater resistance can confuse things.

Now go to the tube sockets. Are all the pins 4 showing continuity to ground? And with power on, you have -11v on C47, so do you also have it on both ends of the upper half of L1? And do you have it on pins 5 of the sockets.

If the tubes are dark but the supply is hot, it pretty much screams open circuit, so doing this will tell you if it is the ground side or the 11v side that is open.