fender deville query.

[theproudguy]

I recently aquired a fender deville 212. Sounds great but cannot get reverb to work. With volume up I get that lovely spring boing over the speakers. When I play my guitar there is no reverb. Any thoughts?

[TomCarlos]

If I am not mistaken, the reverb is driven by an IC. Check to see if you have signal going into U2A, the TL072, Pin 3.

Schematic - Deville ii

[theproudguy]

Don't have foot switch but it only changes channel and drive app.

[TomCarlos]

Got it... I deleted my note... I remember now. The reverb is always on, controlled by the level control.

Check the cable that goes into the Reverb pan. Also, check the input side of the pan, make sure the wires on the connector are ok and no broken wires on the transducer.

[52 Bill]

Check the cable that goes into the Reverb pan. Also, check the input side of the pan, make sure the wires on the connector are ok and no broken wires on the transducer.

Yes, 99% of all reverb problems are mechanical. The fast test on that amp is to switch the two RCA plugs at the tank.

If shaking the tank makes rattling sound through the speaker when the tank is plugged in normally, then you know that the output of the tank is working. You also know that the recovery circuit in the amp is working. Now if you switch the two wires and shake the tank and don't hear the rattling, then you know that the tank input side is is not working. If you do hear the rattling, then the tank is okay and the drive circuit in the amp is not working.

[theproudguy]

Switched wires on tank got no sound upon shake. I assume replacing the tank is the solution?

[Enzo]

Likely.

Pull the pan, and measure resistance across each RCA jack on the pan. The OUTPUT one will have I think about 200 ohms, while the INPUT one will measure less. The readings won't be "wrong", but if they are open, the pan is bad.

You can look inside the pan and see if the little wires from the transducers over to the jack terminals are broken. Sometimes you can repair broken wires there.

[theproudguy]

Output reads as you mentioned but the input shows '0'. So I guess it's time for a new tank?

[J M Fahey]

Not sure how it could read "0" , what meter scale are you using for that?

We expect , as Enzo noted, "some" ohms reading (which is good) or "infinite/open" which is bad.

Can't imagine 0/short .

Please:
1) re-read with meter scale set to 200 ohms and to 2000 ohms, post both results

2) plug the "output" RCA plug into the "input" RCA jack and brush fingers along springs, with Reverb volume on 10 of course and Reverb enables, ... do you hear spring noise through the speakers, even if faint?

3) a closeup picture of the input RCA jack (from the inside of the tank), showing the coil, the RCA and thin wires might help solve this mystery.

[52 Bill]

Agree with Juan and will assume that you meant Open or no reading and not zero ohms.

Remove the tank from the amp and look at the wires on the input side of the tank. There are two thin wires that connect the RCA jack to the transducer coil. These wires often break either at the RCA jack terminals or at the small nylon connector plug. The plug side seems to be the most common.

If there are no broken wires, pull the plug on the connector and read the resistance across the two pins on the coil form. If the coil is good, it should read about 50 ohms. If you get a good reading across the coil, then test each of the wires with your meter to make sure that they are not internally broken.

To fix a broken wire at the plug end, the remnant end of the broken wire must be removed from the connector. I pull off the plug and then use a tiny pair of needle nose pliers to pull out the wire stub. The connector has a self-stripping connector that cuts through the insulation of the wire as it is pressed into the plug. You should be able to figure out how it works by inspecting the metal connector where the wire is inserted.

The end of the wire from the RCA jack now needs to be pressed back into the connector. There is a special tool that does this very easily, but you will have to try and press it in with small screwdriver. Just push down on the wire so that it is pressed into the metal connector deep enough to cut the insulation of the wire and make a good contact through the insulation.

Worst case is to just remove the nylon connector and solder the two wires directly to the two pins of the coil form.

[Enzo]

That is the only way I do it, I remove the little two pin connector entirely, and tack the two wires to the two male pins with solder.

[theproudguy]

Though I won't have the time to attempt this repair until Thurs. I appreciate all the info. These are things I would not have considered. I will keep you informed after I attempt the fix. Thanks everybody.