Yes I'm working through a 5000 system (CD, Cassette, Turntable) for a friend, and have the Power Amp/Tuner nearly finished at the moment.
I'm not convinced that the trimmers need replacing, and have checked all the electrolytic capacitors with an ESR meter. Most were reading more than 30 ohms and have been replaced, with the exception of the 22mfd 16v non-polarised brown ones, they measure fine (<1ohm) and have been left in situ. The ribbon cable for the front panel was broken and had a heavy ribbon cable soldered over it which also had broken. These have been replaced with one flexible small ribbon. The heatsink has been removed, all transistors and insulators cleaned and re-pasted and is back together.
The output relay has also had its contacts cleaned although I really should have replaced it with new, after all it's in series with decent speaker cable so we should give the signal a fighting chance of ending up at the speaker! I will monitor performance and change the relay if it plays up.
The major problem I have is the cord threading and associated spring which seems to have been elongated and jumps off the pulley when the panel is pushed in. I'd like to find the correct threading diagram or a photo but cannot find it anywhere, you think it would be in the service manual. Can anyone help with a photo?