I'm trying to find someone who can repair or assist me in repairing a Kyocera R-661 receiver. The left channel seems to go on & off (mostly off lately.) I took a chance and bought a small septate amp thinking it was the amp. That didn't work, so I know it must be something simple in the pre-amp area. (I had the same problem with the separate amp hooked up.) Also, anyone with access or info on a service manual for this model. Any ideas, anyone? Thanks!