carlsbro solid state reverb unit

[emresound]

hi guys,
I'm trying to get my hands on some info on how to repair a reverb unit. Bit of a long shot I know but I can't seem to find much info about this unit. It's the same as the one in the following link (http://www.jga.u-net.com/reverb.html).

It seems the reverb isn't working and I don't really know where to start with this as I'm kind of a newbie when it comes to reverb and troubleshooting this.

It makes a splashy noise when I hit the reverb tank but no reverberating sound seems to come out, just the clean and that splash when I hit the tank.

Any ideas? I'm sure it's not mega difficult but I don't know where to start.

Thanks

[Jdansti]

Here's some general info on spring reverbs:

http://sound.westhost.com/articles/reverb.htm

Sounds like there is either no signal going to the input (drive) coil or the the input coil itself is bad. Since you get a springy sound by tapping on it, the pickup coil is probably ok. I would start by opening the reverb tank and checking the wiring and mechanical attachments of the coils and springs.

If that looks good, I would cut the problem in half at the input coil. You could disconnect the input coil and replace it with a speaker (I don't know how many watts to expect). Alternately, you could try to measure the AC voltage output going to the input coil. You might want to disconnect the coil when you do this in case it's shorted, but don't leave it connected to the meter for a long time without a load.

If it appears that you are getting signal to the input coil, the coil is suspect. If you have no signal going to the input coil, then you might have a problem with the drive circuit.  Hope this helps!  Good luck!

[emresound]

Thanks for the article, I'm starting to go over this.
I tried yesterday to swap the reverb tank (I have also a fender reverb unit) but it didn't help either so I wonder if the problem might be on the wiring itself. Is that something possible?

I attached some photos of the guts of the unit, maybe someone might have a clue about this specific one (or maybe a similar one)

[Jdansti]

Check the continuity of the cables that go to the tank.  The unit appears to be old, so you should probably check the electrolytic caps for shorts.

[Mark Hammer]

The utput side of the tank appear to be fine from your description.  The question is whether the failure to send any signal successfully through is a result of a problem at the input end of the reverb tank (which can have problems quite independent of a fully functioning output transducer), or a problem in the electronics driving the tank.  Hopefully, this is just a matter of the input electronics, since that may be cheaper and less of a nuisance to repair than ordering and installing a whole new reverb pan.

You may want to try using an LM386-type battery amp to drive the reverb pan input directly.  Just run a cable from the amp output to the the input on the pan, and see if the usual sorts of touching-your-finger-to-the-input-cable noises show up in a reverb output.  If they do, then your pan is in the clear, and you can focus on the driving electronics.