JCM 2000 DSL 401 Troubleshooting reverb problem

[DrGonz78]

I have this DSL 401 that has a reverb problem. The main problem is that the reverb is not working at all. I have checked all the usual suspects: tank, cable,...

[hatcherd]

A customer brought me a Guitar Research T60R Tube (1 12AX7) that the zerner diodes are fried. Does anybody know what value these zeners might be or does...