UPDATE:
Probably against the advice of AK, please do not shoot me, i have gone ahead and recapped just the equaliser, preamp and protect board. Had the parts, unit sitting there so i said why not.
100% sure each cap is done perfect orientation wise and a lovely touch by onkyo is that, on the boards is that the minus and neg are marked on the solder side of the board, found no inaccuracies either. One cap at a time is how i did it.
I did not touch any of the transistors, slowly learning a lesson on this!!!!!
The i took another mad step and cleaned the preamp, equaliser, power and protect board with window cleaner (ammonia free) a super soft brush and rinsed in filtered water, followed by rinse in alcohol.
Far from perfectly clean but a hell of a lot better - unit is now sitting beside a good dehumdifier
It will sit there for a week or two anyway until i am sure everything is dry.
I have a bunch of resoldering to do, lots of ifffy looking solder joints all over the boards.
Question - Do you generally add a little bit of solder just to reflow, or soldapult and then redo the whole thing?
Once all this dries out, i am going to disassemble the rear of the unit and tackle the chassis.
Serious cleaning required. I just do not understand how it got so dirty - someone was using it as a plate for greasy fry ups, and or an ashtray for the old moroccan woodbines.
Meanwhile i am still on the search for the 250k linear dual gang balance pot.
Take the old solder off with desoldering wik clean with isopropyl alcohol and resolder is the best way to do it I've found.
While the boards are off and if your doing a full restoration replace any relays, zener diodes, fusible resistors clean and reseat any heatsinked transistors replacing mica insulators and new thermal grease, take plenty of photos label any disconnected wires, you can use a toothbrush to clean particularly dirty boards along with something like Mr muscle kitchen cleaner (the one in the orange bottle, it even smells nice) make sure it's rinsed properly after.
