ACCUPHASE E-202 restauration advises?

I recently purchased a 30+ years old Accuphase E-202. Some of the knobs make static noise, one channel seems slightly louder, and one of the three speaker connections sounds muffled.
It appears to be completely original and sounds delightful already but I can’t help wondering what it would sound like once serviced and brought back to specs.
Would anyone be kind enough to share their personal experience and suggestions? The schematics, what to look for and some replacement parts suggestions would be greatly appreciated.
Thanks in advance,
Amps that are made by the same people who made an amp 20 or 30 years ago such as ARC or McIntosh and indeed Accuphase needed to demonstrate the long term value they represented These companies intended to show longevity if you invested money in any product they offered by making sure the spare parts were around to surrmount that lifetime of good music needed to convince yourself not just your significant other the obstacle of a very high "initial investment" would certainly reach equity. Thus They will frequently have the integrated circuit boards needed to repair any thing they ever made to make a new one in box from the ground up.
In any other situation unless you are doing it as a labor of love and hobbyist DIYer most audio gear was mid fi at best cheaply made and became obsolete almost immediately. If you blow a board on the Mid Fi stuff forget about finding the right one as an NOS part. I have gone through 3 ebay KA-7100s Kenwood integrateds trying to come up with one that works. This is a paiful battle I surrendered a few years ago. I started only because my son sees the boat anchor I had as A teen, and wanted to know what music sounded like when I was young. It is not repairable nor are the others and no technically adept friend has ever ventured to offer their services.
In your case it sounds like everything can be fixed with fresh new caps some lubrication. It does leave open the one question. Why is it muffled on one side? In your case the muffle is the limiter. I wouldn't send it into Accuphase unless I was rich enough to afford the luxury of a new IC to start and a repair bill in the thousands. If the Muffle goes away with some maintenance, Which you won't know without trying it or pay a Tech a pricy bench fee. It seems your only option is to give it go.
The minute my c-200 control unit (a preamp made by Kensonic Labs and labeled as Accuphase brand) lost a channel I wrote it off but failed to throw it away. A friend of a friend spotted what he thought could be a ... Yes it is but...he wanted it anyway. He was inistent, despite my assuring him that the prognosis was poor and my warning not to bother.
I gave him a very low price to consider. Unless there is a bull market in alluminum casework it a non loss to me. I gave up on mono except for 2 mono blocks a long time ago. All is for the best he has a really nice shiny hood ornament and my concsience is clear, as is the mote of basement starage space it took up.
Fix if easy and don't if not. I can probably find this buyer of broken expensive stuf and get you a token sum for it.
Try Amplifier Surgery

Here is their youtube page:

Check Ebay under ID: amplifier_surgery

I have no affiliation with them. I only found their info from when I was looking to have my Accuphase E-202 restored.
Accutech is Accuphase's official in/out of warranty repair shop here in the U.S., as far as I know.
That amp is built like a tank! Good luck with the rebuild.