Master volume issue with JCM 900 DR

[koffo]

Hi Everyone,

I have a strange issue with my JCM 900 50W Dual Reverb. Basically what happening is that I have both channels that are always maxed out even if I try to turn down the master volume to zero, so it looks like both MV pots are bypassed. I tried already to check and even change both MV pots with no success. I've checkd also the channnel switch, but it is working correctly.

Did you ever had such an issue? Is there anyone that could suggest anything to check?

Thank you all in advance!