To raise finance for this project (damn money) I have been buying vintage HiFi, fixing them and then selling them on eBay. At the moment I am working on a Harman Kardon 730 receiver (amp with built in tuner). Plus a Pioneer SX-5580 which (I believe) is the same as the Pioneer SX-1050 only in black.
The Pioneer 5580 is a real monster, difficult to pick up and move and in a bad condition. It blows the mains fuse on start-up. I have only just got started on this one so will let you know how it turns out.
The HK 730 had no sound from the left channel. It turned out to be a varistor in the Power Amp doing strange things so I replaced both with an 1N4148 and now all is well:
You can see I have also replace those shitty single-turn, carbon variable resistors with decent 20 turn ones. I have also replaced all electrolytic capacitors as they will have dried out after so many decades of use. All lamps now work and it’s had a good clean-out and hoover. This is a highly respected amp, not just because of its looks (which I do love) but also as it has two totally separate power supplies, one for each channel. So two mains transformers, two sets of double (one for the positive voltage rail and one for the negative) mains capacitors and two bridge rectifiers. My amps will also have two totally separate, high power mains supplies and they are just for back-up and charging of the batteries!