DRRI reverb drops out

[rockman627]

I have a DRRI and the reverb works for about 10 minutes then stops. I just saw how to measure resistance on a Reverb pan and I did get 1.2 ohms on the in jack and 250 ohms on the out jack. I plugged a guitar to the reverb return and heard sound. But when I plugged the the guitar to the amp and went from reverb send to my Roland micro cube I got nothing. I measured the reverb transformer and got 1.2k on the red and blue side, 1.5 ohms on the green and black side. I swapped out V3, but I'm not sure of the reliability of the replacement. I think I'll put a known good 12ax7 in and see if that holds out and if it does, buy a new 12at7. Anything else I should be checking?
Fender-65-Deluxe-Reverb-Schematic.pdf

[rockman627]

12ax7 didn't help. Reverb worked for about 5 minutes then just stopped.

[Helmholtz]

To check the reverb driver you can directly connect an 8 Ohm speaker instead of the tank.

Intermittent reverb is often caused by a contact problem (tube socket, reverb cables/connectors)
Also check if the coil wires inside the tank are well connected.

[nevetslab]

You could swap V6 Driver tube with V3, as both are 12AT7's. You can also plug signal into the Reverb Return, which is high impedance, just to verify you can inject signal thru that path. Reverb Pot adjusts level of the signal.

Perhaps there's a bad solder joint in the Reverb Send circuit, assuming both 12AT7's are verified to be working. 12AX7 has way more gain than the 12AT7, though may get loaded down by the Primary of the Drive Transformer.

[rockman627]

Since plugging a guitar into the reverb return worked, I tested the reverb send part of the circuit. I touched up the solder joints, tested the resistors and checked continuity. Everything seemed ok. It started to look like the reverb transformer was the issue. I double checked the reverb send circuit, then ordered a new reverb transformer. That did it. Put in new 12at7's , tested and put her back in circulation. Thanks again everyone.