From what I understand it's the same circuitry as the Super Quad Reverb and the Super Twin Reverb silver faces. Someone on here may know more.
After some wise input from another member here, I checked the electrolytics and load line resistors before going any further. The caps looked good with possibly only a minor bit of leakage on one or it could have been where it touched the cover. The resistors looked as new...clean and bright color bands. I will also get the power tubes tested in the next few days.
That done, I decided to power it up. I let it idol for about 15 minutes and tuned up a couple of guitars. She kicked right in and my pot cleaning was effective as there was no scratchiness at all. I just noodled around at fairly low output gradually getting her cranked into the nasty zone. Tubiness out the wazoo without any pops. The amp seemed to get stronger and more responsive as I went along. I don't know if this was because it sat for so long or if it is a symptom of a problem. Reverb works although I don't know how good it is...seems a bit dull esp. at lower volume. Not sure how to test the reverb tank. All the tone knobs do their thing. After about 15 min it started to get a bit poppy so I backed her down. As I said, everything works except the tremelo which I did not test as I did not have a shorted plug ready. So obviously, I'm very happy that there is nothing big wrong.
It is a heavy beast and not something I will gig with. As you can see from the pics, I will need to probably re-tolex the unit at some point and get some new chrome corners. The grill is probably 8/10 and good enough for me. I will probably take it in next week for a tune up (if I can convince my wife). It's a good thing I have a pickup truck. Here is a couple of pics of the back for the record....sorry they are upside down. My picture hosting site will not let me flip them for some reason. Oh well....just turn your monitor upside down or do some contortions.
Thanks everyone for the warm welcome