Dlx Rev rebuild- totally dead.

[Sea Chief]

Hi- recently p-t-p rebuilt a 65 RI dlx reverb, so effectively a completely fresh p-to-p build. Tested totally & comprehensively with a pro builders before first ON.. and away I went/ been fine and sounding good for 2 weeks.

Today turned off as usual after a play, went away for 3 hrs, turned on again as per norm- zilch. . Completely no sound whatsoever/ nothing getting to spkr. Never had this on an amp before

Leads checked. 6v6 pair changed/ same. Tubes lit usually. Im not doing anything stupid I'm pretty sure.

Christ this is really worrying- where do I start?

[Pls only reply if you intend to help: I cant deal with unpleasant replies with this problem. Dave_H, SteveA, J.M.Fahey etc.. please just leave me alone for this thread].

Thanks SC.

[pdf64]

With your ear next to the speaker, is there any hiss / hum?

See http://www.geofex.com/ampdbug/ampdebug.htm

[nosaj]

Hi- recently p-t-p rebuilt a 65 RI dlx reverb, so effectively a completely fresh p-to-p build. Tested totally & comprehensively with a pro builders before first ON.. and away I went/ been fine and sounding good for 2 weeks.

Today turned off as usual after a play, went away for 3 hrs, turned on again as per norm- zilch. . Completely no sound whatsoever/ nothing getting to spkr. Never had this on an amp before

Leads checked. 6v6 pair changed/ same. Tubes lit usually. Im not doing anything stupid I'm pretty sure.

Christ this is really worrying- where do I start?

[Pls only reply if you intend to help: I cant deal with unpleasant replies with this problem. Dave_H, SteveA, J.M.Fahey etc.. please just leave me alone for this thread].

Thanks SC.

Check your voltages on the tubes. Tubes being lit only signifies your heaters are working. Got a blues jr in doing the same thing HV on transformer was dead. Same symptoms as yours. So check the voltages on the tubes.

nosaj

[Justin Thomas]

If the pilot light is lit, along with all the heaters, I'd check the rectifier tube. Got a spare?

Justin

[Sea Chief]

With your ear next to the speaker, is there any hiss / hum?

See Tube Amplifier Debugging Page

Great link pdf64 (saved/ top of my AMP folder list that is now), so went thru all the stages and checked off down to the phase inverter tube (I stuck in an old mullard 12at7 from my 70's wem) tried my luck swapping in a JJ for it & bingo! that was it. So it seems anyway.

Thank feck for that- had worries it was the bias circuit/ the PT gone tits up.

..And relax. Thanks chaps. SC

[Dave H]

[Pls only reply if you intend to help: I cant deal with unpleasant replies with this problem. Dave_H, SteveA, J.M.Fahey etc.. please just leave me alone for this thread].

Thanks SC.

OK will do but I don't remember ever leaving an unpleasant reply.

[Sea Chief]

OK will do but I don't remember ever leaving an unpleasant reply.

Not you Dave H.

Its Dave_H Im referring to: leaves me threatening PM's & unpleasant replies on threads (meant to be a moderator.. but honestly with such behaviour & approx 750 posts only.. s'thing definitely ain't quite right). I suggest he just doesnt reply on my threads, please.

[Enzo]

It is just a tube amp, like any other. They fail all the time, every day people write here to report amps no longer making sound. Approach it like any other amp. MAKE SURE the speaker and speaker wiring is intact, check all power supply voltages, then check for B+ at the plates of each tube, then check for voltage on the cathodes to demonstrate the tubes are conducting. Then apply a signal and trace it stage by stage.

There is even a troubleshooting chart over at geofex.

[Dave H]

Not you Dave H.

I'll let you off then.

[Diablo]

For faster troubleshooting, do the pop test. Connect your black lead of your digital voltmeter to amp chassis/ground, and touch the red probe to the grid of each tube. Start at the output end and work your way toward the input end. The amp should pop every time you touch the grid. The pops will be quietest at the output tubes, and get louder as you move to the input. Any tube that doesn't pop, tells you the problem is right there. Once you find the problem tube, try swapping the tube. If that doesn't work, check out the circuit for that tube socket.