Danelectro DM10 (Silvertone 1449)

[xtian]

I updated this amp, and it's working well, except for the Tremolo. I can hear the trem ticking quietly, and the speed of the ticking varies with the Speed control, but no Tremolo effect on the output. The voltages on the tremolo 12AX7 measure within spec, except that I cannot read the voltage on the plate of the first triode (pin 6)--probably because it's oscillating? But the cathode (pin is NOT oscillating--stays steady at 1.8vDC.

I tried swapping in a brand new 12AX7 with no change. Any tips for troubleshooting this design?

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[Stevem]

Are C4, 5 and 6 good?
From what I recall these amps do not need the foot switch for function, but is the foot switch jack shot and it's internals have spun around and shorted out?

[xtian]

Yes, C4-6 are good--again, the oscillator is working. Measuring pin 6, plate, of the oscillator, I see a sine wave that varies from 4 to 8 HZ depending on Speed control. The voltage swings from 60 to 298, or 238v p-p. The cathode (pin of the same triode does not swing at all. Steady 1.8v. This is the part that should be swinging the voltage on the power tube's cathode, but it's not.

Should I be seeing any AC (AC = the tremolo's sine wave) on the wiper of the Tremolo Strength control?

[xtian]

OK, problem solved. Trem Strength pot was twisted in its socket, and had shorted connections.