KUSTOM DEFENDER 112 TUBES OFF

[Travis8]

Hi everyone!!


I have a kustom defender 112 that doesnt turn on power tubes..

I check fuses and they are all ok, I read pin 2 and 7 witch correct 6.3vac and the test point on the amp looks correct values... also I resolder all the pinout

Some ideas o recommendation?

Thanks.


https://el34world.com/charts/Schematics/files/Kustom/Kustom_defender112.pdf

[Travis8]

between GND and F4 is 3.2VAC, also F4 is ok.

[Travis8]

They doesnt light up and the amp doesnt sound. 12ax7 looks fine

[sluckey]

Set meter to read AC volts. Connect one probe to pin 2 of an EL34. Connect the other probe to pin 7 of the same EL34. What voltage do you have?

[kagliostro]

Did you had a filament chek ?

Franco

[Latole]

between GND and F4 is 3.2VAC, also F4 is ok.

This look good , follow Slukey advice.

[Travis8]

Set meter to read AC volts. Connect one probe to pin 2 of an EL34. Connect the other probe to pin 7 of the same EL34. What voltage do you have?

I turn it on right now to check it and the tubes shine!!!!!!!! I dont understand why yesterday not... Some ideas ?

I read 6VAC.

[Travis8]

I check that the amp turn on and the tubes lights up and the amps sound, but after a minute they amp starts sound quieter and quieter and finally it haves no sound and no light on tubes.

[sluckey]

I check that the amp turn on and the tubes lights up and the amps sound, but after a minute they amp starts sound quieter and quieter and finally it haves no sound and no light on tubes.

Leave your meter connected to measure filament voltage as I said earlier. What voltage do you have when the lights go out? I suspect the filament current is causing a poor connection to open up. Top suspects would be J34 and J35. It's a very simple circuit. Should be easy to find.

Set meter to read AC volts. Connect one probe to pin 2 of an EL34. Connect the other probe to pin 7 of the same EL34. What voltage do you have?

[Travis8]

I check that the amp turn on and the tubes lights up and the amps sound, but after a minute they amp starts sound quieter and quieter and finally it haves no sound and no light on tubes.

Leave your meter connected to measure filament voltage as I said earlier. What voltage do you have when the lights go out? I suspect the filament current is causing a poor connection to open up. Top suspects would be J34 and J35. It's a very simple circuit. Should be easy to find.

Set meter to read AC volts. Connect one probe to pin 2 of an EL34. Connect the other probe to pin 7 of the same EL34. What voltage do you have?

When I turn it on 6.04VAC, then its starts going down step by step after a minute, and finally when tubes stop light AC is: 0 VAC its still sound a little bit with 0VAC but finllay stop sound.

[sluckey]

When I turn it on 6.04VAC, then its starts going down step by step after a minute, and finally when tubes stop light AC is: 0 VAC its still sound a little bit with 0VAC but finllay stop sound.

As I suspected.

I suspect the filament current is causing a poor connection to open up. Top suspects would be J34 and J35. It's a very simple circuit. Should be easy to find.

Other suspects would be a bad connection at the fuse holder or tube socket or even a bad trace on a circuit board if filaments are run on the pcb.

[Travis8]

When I turn it on 6.04VAC, then its starts going down step by step after a minute, and finally when tubes stop light AC is: 0 VAC its still sound a little bit with 0VAC but finllay stop sound.

As I suspected.

I suspect the filament current is causing a poor connection to open up. Top suspects would be J34 and J35. It's a very simple circuit. Should be easy to find.

Other suspects would be a bad connection at the fuse holder or tube socket or even a bad trace on a circuit board if filaments are run on the pcb.

J34 and J35 looks good. How can I check it properly?

[Travis8]

Photos

[Travis8]

I check continuity and J35 goes correctly to R101 and pin 2 in both tubes and J34 goes correctly to fuse holder, R102 and pin 7 in both tubes.

[Travis8]

I'm a bit lost, some ideas?

Thanks you everyone, for real.

[sluckey]

Do you still have 6VAC between J34 and J35 when the lights go out? If so,

Reflow the solder connections for J34, J35, the fuse holder, and pins 2, 7 of the power tubes. Look for a broken pcb trace between J34, J35, the fuse holder, and the output tubes.

If you do not have 6VAC between J34 and J35 when the lights go out, examine the wire between J34, J35, and the PT. If this is the case then the PT is likely bad.

[sluckey]

This may help. Re-flow all the solder pads I circled, top and bottom of board.

[Travis8]

I resolder it and also I check that J34 cable was a little bit bad. Now it´s works!!!

Thanks!!!