Non-functioning, funky old Guild Dynamic Reverb System

[NeoFauve]

Is anyone familiar with this beast?

It's a solid state gizmo w/ and 8" spring tank in it.
Controls are - On/Off switch, Volume, Reverb. (pretty sure that's how they're labeled.

It powers up and signal passes through it quietly, but with no verb. But if I give it a clunk on its top, it makes that crashing spring sound, still not affecting any guitar signal going through it.

I'm no techy, but I can work a soldering iron. I'd love to get it working.
Any clues??
I have a could of decent photos, if anyone want to have a look.


NeoF.

[Old Tele man]

sounds like either:

A) the drive signal into the reverb unit isn't working; check the drive tube (transistor?) for an output signal.

B) the reverb unit input winding is broken; use a ohmmeter and check for an open circuit.

The fact that you can make the reverb unit produce a "crash" sound by hitting it, indicates that the reverb output circuit is working...that's why you suspect the input circuit is the problem.

[NeoFauve]

I just recently bought a meter, so maybe this will be a good guinea pig.
Are transistors something I want to check with the unit turned on?
"Input winding?" There's a transformer, do you mean its windings?
One thing I notice is that the transformer doesn't quite seem to fit in its bracket correctly. Maybe it's been replaced over the years.