Weak Spring Reverb

[bobloblaws]

I have a reverb tank for a 1968 Super Reverb that is barely working. There is some output, but very faint, it is hardly there. I pulled the tank out of my 68 Custom Reissue Deluxe Reverb and confirmed that the reverb circuit in the Super is good, it's the tank itself (also confirmed the problem isn't a bad cable). I measured resistance on the bad tank, sleeve to tip on the input I get 174 ohms, on the output I get 175. This quite a bit different than the good tank from the DR which reads 3 ohms sleeve to tip on the input, and 247 ohms on the output. Any ideas?

Bob

[g1]

Sounds like the wrong tank. Does it have a number stamped on it?

[Leo_Gnardo]

I measured resistance on the bad tank, sleeve to tip on the input I get 174 ohms, on the output I get 175. This quite a bit different than the good tank from the DR which reads 3 ohms sleeve to tip on the input, and 247 ohms on the output. Any ideas?

The tank might not be bad, however it is certainly the wrong tank. Typical readings for tanks that work with Fenders, 1 ohm DC resistance in the input transducer, about 200 ohms more or less on the output.

[bobloblaws]

Sounds like the wrong tank. Does it have a number stamped on it?

Yes, the number is 500-048516

[g1]

Also, long ago these tanks were still repaired and the individual transducers were available. If the tank has the right number, it's still possible it was originally the right model tank, and someone replaced the input coil with an output type.

[g1]

Yes, the number is 500-048516

Ok, that is a Gibbs number and not the correct accutronics type for Fender. It should be useful in other amps, but not this one.
You need 4AB3C1B type tank.

[Mick Bailey]

Can you post a pic of the inside of the tank?

[bobloblaws]

Ok, that is a Gibbs number and not the correct accutronics type for Fender. It should be useful in other amps, but not this one.
You need 4AB3C1B type tank.

Thanks, at least I can stop troubleshooting now. The owner of this amp got ripped off, and not just for the wrong reverb tank. I assume you got that info from a website somewhere. Can you point me to it?

[bobloblaws]

Can you post a pic of the inside of the tank?

Apparently it's the wrong tank for the amp, but for what it's worth:

[bobloblaws]

Sorry for going off topic, (at least it's my own thread I'm hijacking) but while I have your attention, quick question regarding the tremolo on this same amp. There is no audible tremolo effect but when I engage the it with the foot pedal I can see the light inside the "bug" flashing and the speed varies according to where the speed control is set. Can I rule out that component as a potential culprit or is it possible that it might still be defective?

[Leo_Gnardo]

Thanks, at least I can stop troubleshooting now. The owner of this amp got ripped off, and not just for the wrong reverb tank. I assume you got that info from a website somewhere. Can you point me to it?

The number G1 quoted is the Accutronics part number Fender's been using for decades. New replacement part numbers are the same, from several manufacturers. CE/Antique/tubesandmore.com has a wide variety of tanks PLUS a couple variations on the Fender standard, with short and long reverb decay times. I don't know if there's an equivalent vendor in Canada, sure would be nice if you can find one.

Gibbs was another separate company, all their tanks (that I've seen anyway) are about 5" x 9" compared to the standard Accu-style tanks about 4" x 17". Somebody must have punted and stuck that Gibbs in the Super Reverb, hoping that it would suffice. Whoever tried to fix that amp may have been ignorant of the fine points of reverb tanks, and apparently other things as well.

On the vibrato bug, there's been a rash of them going bad in recent years. Many times I see the photocell has a lead that has let go, loosened up but not yet fallen off. In any case it's discontinuous & needs to be replaced. I make my own "bug" with a super-bright orange LED (yellow or red also work well) and the photocell sold by CE/Antique as a replacement for Morley pedals. Plus an inch of black heat shrink tube. An advantage of the LED is it reduces the click noise that accompanies vibrato use to an inaudible level. Or you can buy a bug, ready-made with neon lamp from them or several other sources, and live with the click.

[bobloblaws]

The number G1 quoted is the Accutronics part number Fender's been using for decades. New replacement part numbers are the same, from several manufacturers. CE/Antique/tubesandmore.com has a wide variety of tanks PLUS a couple variations on the Fender standard, with short and long reverb decay times. I don't know if there's an equivalent vendor in Canada, sure would be nice if you can find one.

Gibbs was another separate company, all their tanks (that I've seen anyway) are about 5" x 9" compared to the standard Accu-style tanks about 4" x 17". Somebody must have punted and stuck that Gibbs in the Super Reverb, hoping that it would suffice. Whoever tried to fix that amp may have been ignorant of the fine points of reverb tanks, and apparently other things as well.

Thanks. The owner says he has another tank kicking around we can try. If it comes to it we can get one from Antique, I order from them quite a lot.

[Jazz P Bass]

Sorry for going off topic, (at least it's my own thread I'm hijacking) but while I have your attention, quick question regarding the tremolo on this same amp. There is no audible tremolo effect but when I engage the it with the foot pedal I can see the light inside the "bug" flashing and the speed varies according to where the speed control is set. Can I rule out that component as a potential culprit or is it possible that it might still be defective?

Measure the resistance on the two legs that are not the lamp supply.
It should vary with the lamp blinking.
I am thinking the high value should be upwards of 1 meg.

[Enzo]

The blinking light means the light bulb half works, but doesn;t mean the photocell half works.

You need a pan that says 4AB or 9AB or 8AB at the start of the number.

[cjenrick]

been having good luck with the MOd tanks, cheap but hi quality,