Reverb not working

Hi,

The reverb on my Mark V has stopped working. On the footswitch, the green light goes on and off, but this does not change the sound. I've checked the connections on the circuit board and also the reverb tank and everything is tight. I've also rolled the tubes but it did not make a difference. No reverb on any channel, any mode.

So, just curious if there is anything else I could try. I'm guess it is a JFET or something in the electronics that has gone bad. Amp is from late 2011.

Sidebar question: is there any way to turn off the reverb without the footswitch (other than turning down the levels on the back of the amp)?

Thanks for any feedback.

mace said:

Sidebar question: is there any way to turn off the reverb without the footswitch (other than turning down the levels on the back of the amp)?

Click to expand...

I crossed up the wires once on the reverb tank and that made the reverb inoperable.
Now, I don't use the amp reverb (I got a Boss RV-500 for that) so I pulled the wires and tank out of the shell.

Does the reverb "crash" when you rock the amp?

I can faintly here some reverb noise through the amp when I "plop" the amp down. So, this means the reverb tank is hooked up properly and the tubes are working etc. So, that's good to know. I hadn't thought of banging on the reverb tank! Good troubleshooting advice.

The usual spring noise when gently moving the amp doesn't seem to be there. I loosened the screws holding the reverb tank and it didn't seem to make a difference.

Could there be an internal, physical problem with the springs? I've never had a reverb tank "go bad". Any further advice would be great....like, is it possible to open up the tank and troubleshoot?

Can the tank from the TC-50 go into the Mark to try it (is it compatible signal-wise)?

A crash when you rock it or bang it indicates that there is output from the tank. The tank can still have an issue. I would try the tank from another amp.

I hooked up the TC-50 reverb tank tot he Mark V and couldn't even get a normal tone. The Mark V tone was very low gain and soft with the TC-50 tank connected, both with and without the reverb engaged via footswitch (reverb volume knobs all at 12 o'clock). In fact, channel one was very faint, barely audible and channels 2 and 3 were very low gain and low volume. I rattled the reverb tank and could hear it through the amp so it was hooked up properly. But, the guitar tone was very strange and super weak. The reverb tank cover on the TC-50 combo was a super cheap *** piece of plywood and two screws were stripped when I took it out of the bag. Seemed very un-Mesa like. At any rate, I''m not sure the TC-50 reverb tank is compatible with the Mark V, doesn't seem so.

When I unplugged the reverb connections from the tanks there was no sound out of the Mark V. I then re-hooked up the Mark V tank and it behaved as before with no reverb but seemingly normal tones. This included the faint, very intermittent crackling which has been present for a while (not a tube issue, all tubes have been rolled). Not sure if this faint crackling thing is related to the lack of reverb (some electronic component failure?). The crackling can only be heard when the guitar is not being played but the amp is powered up.

One side note: When I reconnected the pedal board to the loop it made a god-awful squeal when I engaged the loop. I then just hooked up an instrument cable in the loop and no issues. Then, I reconnected the pedal board and it was normal. Not sure what that was about. If I connect the pedal board backwards there is usually no tone (only a chorus and delay in the loop).

Thanks for any more advice on what to try! I'm thinking the amp needs to be taken to a tech for the reverb issue and just get a general "going over".

mace said:

One side note: When I reconnected the pedal board to the loop it made a god-awful squeal when I engaged the loop.

Click to expand...

Sometime ago I was getting this same high pitched squeal along with a hum that would get louder and louder in time. I have a four port input jack on my pedal board and using pancake connectors would create a connection between the four. I found that it was this "four port connection" creating the squeal and hum. I switched out and then wrapped electrical tape around 2 of the 4 connections in case they shift and make contact with each other again.

Question: does your amp work/sound normal with the reverb tank disengaged/disconnected?