New Express 5:50 for $450! Reverb needs FIX!!

[fredfunk]

Just picked up my first Tube Amp - a MESA Boogie Express 5:50 for $450!

Great tone, perfect cosmetic condition, but the reverb circuit is not working... I checked all the connections, and tried both channels. I tested the reverb tank and it looks good (Black = 250 ohms, White = 1.2 ohms). I rolled the tubes (no problem with #5). Soooo.... it looks like it must be the FETs on the mute circuit. If anyone has a schematic, or experience please send!

 

[fredfunk]

 

[fredfunk]

I found a schematic and I believe the two FETs that may need to be replaced.

 

[fredfunk]

 

[fredfunk]

Is "J175 mute" one of the suspect FETs?
How can I tell if it's bad?

THANKS!