Reverb troubleshooting help

I just bought a .50 Caliber combo. It appears to be from the mid 80's. The previous owner told me the reverb worked but was just weak. I don't think so. If I turn the reverb to 10 I hear a little static/noise, but no reverb at all. I changed the tube and verified very low ohm rating from in to out on the tank. Any other ideas short of a technician?

Clean all jacks and plugs.

Try a different cable.

IME cables, connectors and corrosion are the cause of many problems.

Isn't the (tiny) reverb tank inside the chassis on the .50 Cal? And hard wired to boot, although the teensy connections at the tank end are removable. The wire connecting the tank to the circuit board is fragile, to say the least. That's where I'd look.

Thanks for your help. The (tiny) reverb tank is mounted to the right side of the cabinet (facing from rear). I will check the wires tonight. I had been hoping to avoid disassembling the chassis, since I broke one of the nylon clips that holds the tube cover plate the first time I removed it to look at the tubes. That little Nylon piece has been there since 1985-7 and I broke it day 1. Anyway, I tried changing out tubes and the sound only got worse and still no reverb. I hope it is the wire, but I also have a well respected tech living near me who can give her a thorough service and I had planned to send the chassis to Mesa to have the Lead Drive/Master mod done.

Which brings up another question. Does anyone have that mod and do you think it is worth it? The gain difference between clean and Lead is so drastic that I'm thinking I need to just push the clean channel with my Bogner red pedal for the "mid-gain" and keep the amp in original condition.