Super Reverb weak vibrato

[Prairie Dawg]

Got an AB568 Super Reverb here that I'm overhauling for a guy-usual 40 year old Fender amp stuff, nothing of great import but the vibrato is very weak, barely audible. You can see the neon lamp in the roach doing its thing-I'd bought another on the offchance that it was kaput. There's three capacitors in a string-2 .01s and a .02 that I may test tomorrow. Just wondering if anyone's had a similar problem and what fixed it.

I haven't yet gotten to the reasons the reverb doesn't work either but I'm thinking transformer because I can smack the tank and get noise but nothing comes through from the preamp, and there's some suspicious looking splooge coming out of the reverb transformer.

Thanks, y'all

[52 Bill]

Did you try changing the trem roach? Even if the lamp lights up, the photo resistor could be weak causing your problem. If the caps are bad, the oscillator will not run, causing no effect because the lamp will not flash.

The photo resistor simply grounds out the signal in time with the flashing lamp. It is wired in series with the "Intensity" control. If the roach is ok, then check the pot and the wiring.

The reverb drive transformers will fail. I've seen them drip wax before, but that doesn't really mean the tranny is dead. Test it with a meter and see if the primary is open. You can also test it with the shorted turns tester at R.G.'s site. Obviously, also check the 12AT7 driver tube and related circuitry.

[Prairie Dawg]

Did you try changing the trem roach? Even if the lamp lights up, the photo resistor could be weak causing your problem. If the caps are bad, the oscillator will not run, causing no effect because the lamp will not flash.

The photo resistor simply grounds out the signal in time with the flashing lamp. It is wired in series with the "Intensity" control. If the roach is ok, then check the pot and the wiring.

The reverb drive transformers will fail. I've seen them drip wax before, but that doesn't really mean the tranny is dead. Test it with a meter and see if the primary is open. You can also test it with the shorted turns tester at R.G.'s site. Obviously, also check the 12AT7 driver tube and related circuitry.

The roach was the guilty party, and this amp had a bad reverb transformer. I took the low road and subbed out a new roach I had, and borrowed the reverb transformer from my Princeton Reverb that's in pieces.

All's well that ends well.