Hi. Yes, the power supply and audio amp ARE all in one assembly, and that assembly is what I have halfway out. To release it from the plastic frame which holds the whole set together, (and considering that it probably hadn't been apart since manufacture), there are plastic lengths which slide into plastic slots (makes it sound easy!) but dust in between,not much clearance, and a barbed clip on the side of the mainframe closest to the cabinet front, which I had released, it still didn't want to come out, and I have had no prior experience with the model, so, wiggling and levering to get the power amp/supply module out, may have caused the wires to break. There are many wires running together, not exactly a harness, but all crammed into a plastic channel which is part of the mainframe, right next to the end of the removed module, and the wires only just long enough for the purpose. You can't see where they go after they leave the module, some go between boards that can't be removed as they have the bandswitches and front panel controls mounted to them. If you tried to take it completely apart there'd be lots more wires broken off, as they are single strand wires (possibly knicked partway through when originally stripped of insulation), soldered on the foil sides of boards with no anchorage and no markings.
I was looking on line for a better service manual, and I found one that looked like it might have been different. The site said ALL FREE, and I signed up, but then they wanted credit card details, on the other hand promising that I would never be charged, it was just to prove my identity. I thought it a bit fishy, so chickened out.
For the record, the faulty transistors I replaced were T608 (s/c base to collector) and T609 (s/c base to collector as well) They are in circuitry which feeds power from 9v battery or the bridge rectifier through numerous sections of the sliding switch that covers the mains socket or external DC input, depending on position of the spring loaded sliding plate. I couldn't manage to remove the sliding plate to get to the switch sections underneath (you can't see the actual switch contacts) so I was in with the ohmmeter, trying to figure out the path between p/s and just about everything else, when I discovered the broken wires.
The power module PC board has another board slotted and soldered into it at right angles, the other board has mounted on it a row of front panel potts and switches, including the main power and dial lamp switches. It is this larger board which has the severed wires. I carefully looked for stubs of broken wires, but when I tried to get agreement between the schematic and how it looked in the set, I couldn't verify what I thought. I've had past situations where design modifications haven't shown up in the schematic, this could be another...
Thanks for your interest.
Technomaniac.