I’m sure you aware how awesome this piece is but in case you’re not here is some readings for you.
https://audiokarma.org/forums/index.php?threads/is-the-pioneer-c-91-any-good.1039240/
There is much more there so google ahead.
I’ve got it as non working unit and rebuild it for myself replacing all input selector relays and tested close to threshold electrolytic capacitors. Physically unit is very good shape and looks gorgeous. Every function verified and remote control included. Will demo. Originally this unit was sold for $2700 that is about $7000 in today’s money and it shows why, only best parts were used at the time, it’s gorgeous and sounds stunning.
I’m retired electronic engineer on a mission to save great electronics of the past for future generations to enjoy. Check “more ads by this user” for more vintage electronics. Local cash only sale, proceeds goes to homeless veterans charity. Trades and equipment donations welcome.
I can service your own equipment as well. Text me for any questions you might have.