pioneer sx636 reciever

who would this be good to send to to get repaired ,i love this thing an one channel is acting up
This was my first real audio component. I always thought the tuner was very good, but the amplifier section was just ok and after a few years, I went with separates. When I did restore a vintage receiver, it was a Marantz 2216B and later a Marantz 2240.

If you love the Pioneer and it is not too expensive to repair ($200 or so), I would probably do it. Buying a quality new receiver with a very good tuner would have you looking an Outlaw RR2150, which is $600 or so new.