I feel like Ron, and feel rather speechless (yeah, right). Your cabinet restoration is absolutely gorgeous, you really know your way around some wood. Your unit looks alot like the Montgomery Ward console that I had, except mine had the side-firing woofers like the Maggies and also had the same metal chassis. I thought it was a Maggie amp when I first removed the back panel.
Electronic Issues? There is so much to learn. I think it helps to know how semi-conductors work and what role they play in the scheme of things. Capacitors, transistors, resistors, tubes, diodes, bias adjustments...the list goes on.
Speaking for myself, I had to break it down to the component level...Read up on how each part worked in conjunction with others, how they prevented unwanted DC voltages in certain sections of an amp to keep from frying a transformer and damaging speakers, etc. You wouldn't want to put a fresh, new battery in a car that still has a bad Alternator, Generator or Voltage Regulator, so some detective work is in order.
Just like that silly song..."The hip bone's connected to the knee bone, the knee bone's connected to the blah..blah..blah.
Capacitors, fuses and tubes are labeled with their values, resistors are color-coded, transistors and diodes should have some very small numbers printed on them. Those numbers can be cross-referenced for suitable replacements.
Getting a schematic for the amp/receiver also helps. Even though most semiconductors are labeled, it helps to know what voltages/tolerances are acceptable. I tweaked an amp's controls (unlabeled), thinking that they were volume/gain controls when in fact, they were for bias.

The amp was hot to the touch, enough to cause a blister on your finger. I only ran it for a few seconds before I realized what was going on. This was a 70's unit, and none of my older Maggies had a bias adjustment, so getting a schematic saved the day.
I would advise checking out all the old posts. There is a wealth of info there, including what precautions to take. Learning how to use a soldering/desoldering gun, signal tracer, multi-meter and scope (for the real serious folks) are essential. A signal tracer can help you find that "weak link" in the audio chain. There are also books out there on how to repair Electronics without a schematic...I think I have two volumes back in my workroom.
I'm not encouraging you to get in there and get electrocuted, fry the unit and burn down the house, but doing alot of reading to get a feel on how these things (a basic amp/receiver) work. Some folks like to snuggle up on a couch close to a fireplace reading a classic novel, but given a dry manual/schematic and a shot of Brandy anyday, and I'm a happy camper snuggled up, too...LOL!
Once again, I am not a certified/licensed Tech. Just an amateur who's managed to work around the audio obstacles that I have encountered over the years. There are plenty of techs and other experienced folks here at your disposal who can help walk you through your issues.
We all had to start somewhere even before the formal training. If you're leary about doing it yourself, but can afford it, then by all means, take, send, ship it to a qualified/professional individual who knows what (s)he's doing. --BB
Bobby Basham
Tucson, Arizona (
rwbasham@yahoo.com)