Sony TA-E77ESD Needs Repair - Any Advice?

I have a Sony ES TA-E77ESD preamp in pretty good working order, but has some issues:

- Static when volume knob turned
- Digital inputs do not work
- The sound processing goes in and out (sounds as though applied EQ is going "on and off" randomly while using)

Sony nor any other service facility will repair this unit due to its age. Does anyone know of a resource for servicing this unit? Has anyone had similar issues?

It might be time for a new preamp, but this is built like a tank and I'd love to keep it going. 

Thanks for any leads.
Time to get something new. Why fool with a 30 year old preamp that can’t be serviced?
To much money to fix dump asap.

Really? Supposed to be a great unit.
Try contacting Joseph Chow of Audio Horizons. He also has a repair/modification company called Component plus, he can tell you whether it's worth fixing or not.
miko71, thank you for the reference. That's what I was looking for - someone who still services these old units out of the love for keeping them going. 

I'll contact him - seems like my only hope. 
Please let me know what you find out!
Keep us posted should you consult -Joseph Chow.
I contacted Joseph and he responded quickly. Not necessarily offering repair service, but he gave me advice to deal with the static on the volume knob: using contact spray inside the volume pot.

I removed the cover and unfortunately found that the volume pot on this unit is sealed in a square housing, and is rather difficult to reach. I did manage to get the contact cleaner straw inside a little hole in the housing and spray a few shots. It apparently was enough, as the static is gone now.

Haven't asked him yet about the sound processing issue - but I imagine that will be hard to fix as it's so intermittent. The digital inputs have never worked and obviously don't hinder the use of the machine.