I've got one, the reverb is connected by 2 rca jacks inside the amp. If you take off the back grill and look inside you will see the valves. On the right hand side there are some small Ecc83s. The jack runs up to the right of the 1st one near the transformer. You might find that the screws have come loose and its lifting off the base of the amp, especially if you've upgraded the speaker, beefier magnets can rip the screws which hold the tank down out the wood over time.