Try contacting TAP electronics in Buena PArk, CA.
4 responses Add your response
who specializes in repairing and restoring vintage Yamaha gear.
I believe he stocks many original parts, and is aware of tweaks and upgrades to enhance reliability.
His prices are extremely reasonable... he does this more for the love of restoring these beauties than for making tons of money.
You can find him by searching the AudioKarma.org forums (member lookup, or just post).
He's located in Maryland.
I live in California, and don't think twice about shipping my Yammies off to him - he's worth it!