MV Super Reverb Trem and Reverb

[jim]

The amp sounds nice now but the verb and trem are not happening. I have never played one of these before--they are a bit bass heavy in tone. (and a real hernia maker to lift)  The trem effect is very low but I can see the bug flash and I'm thinking the photo cell is weak.  The verb is totally DOA with my known good tank even if I shake it. I can't make it even buzz.  The tube voltages match the ones listed in Tom Mitchell's "Repair Your Own Amp" for the Super so I'm thinking its the reverb tran.  I suppose checking the windings or substitutuion is the only way to know.  Before I plug in the iron--am I on track?  Thanks, Jim

[HotBluePlates]

Vintage Super Reverb or new build?

The verb is totally DOA with my known good tank even if I shake it. I can't make it even buzz. 

If the tank doesn't make a crash when you shake it, the problem is in the reverb return path.

You post sounds like there is another thread on this amp. Is there? Do you have a scope/signal generator? It's not absolutely necessary, but it would help you see how far an applied signal gets through the circuit. However, the tank crash test tells you the recovery stage ain't right.

[sluckey]

The trem effect is very low but I can see the bug flash and I'm thinking the photo cell is weak.

I agree

The verb is totally DOA with my known good tank even if I shake it.

First thing to do is replace V3 and/or V4. Next, there are a couple easy checks you can do to determine if the problem is with the driver circuit (V3) or recovery circuit (V4).

Testing V3 driver circuit... You need a test speaker connected to a RCA phono plug. Pull the output tubes for this test. Disconnect the cable from the REVERB INPUT phono jack. Connect your test speaker to the REVERB INPUT phono jack. Plug a guitar into the VIB channel. You should be able to hear the guitar thru the test speaker. Volume and tone controls will effect what you hear. The volume should be a comfortable bedroom level. If so, the reverb driver V3 circuit, including the reverb transformer are OK.

Testing V4A recovery circuit... You need a special guitar cable, standard 1/4" phone plug on one end, RCA phono plug on the other end. Put the output tubes back in the amp. Turn all controls to zero. Turn the MV to 10. Disconnect the cables from the REVERB INPUT and REVERB PEDAL jacks. Connect a guitar to the REVERB INPUT jack using your special cable. You should hear your guitar thru the amps speakers. The REVERB control acts like a volume control. If so, the reverb recovery circuit V4A is OK.