Yeah, he's asking for a tech, but....
Cleaning the switches and controls in the G8000 is a big job, you have to actually dismantle the unit substantially to access the switches.
Just quirting deoxit D5 in there does not solve the issue, it will possibly give you a temporary band aid, but the problem will always come back.
The Alps switches that Sansui and Pioneer used, have silver plated contacts, after 35 years, there is a lot of black tarnish on those contacts, squirting deoxit in there can dislodge and/or soften some of this tarnish which can foul the contacts sometimes...
So....I prefer to remove the switches and dismantle them, you can use a piece of paper soaked in deoxit to clean the spring loaded contacts, then I use a fibreglass brush with deoxit to remove the black tarnish. You do not want to use anything too abrasive as you will remove the silver coating, and you really don't want to do that.
After you have deoxited the switch, you then need to apply deoxit SN5 (shield) which lubricates and protects, just using Deoxit DN5 only leaves a fresh surface ready to oxidise once its dried out.
It is quite the mission, I have done this to every amplifier I have restored, and my own, except my G22000 which I need to do.
Once this is done, the unit will sound great, it improves the quality of audio as well as stops the drop-outs...
If you care a careful methodical person you might be able to do this yourself, you need plenty of patience though.