Three days ago when an attempt to record a tape was made my GX636 kind of said it had a headache and wasn't in the mood and maybe I should go away. Sigh. Actually over the past several months the record level has had to be continually boosted higher to get adequate levels, so I'm not entirely surprised. Checking it has determined that: Playback works well. When in record mode: both right and left tracks are erased. no audio signal comes through when the source / tape switch is in source position. a hiss can be heard in both source and tape positions of the tape / source switch. All switch lights indicate the switches are working except the tape mute switch.. I have: Removed the front and back cover. Checked the fuses - all good. Used Deoxit on every switch and contact, including those under the bottom bar. Cleaned the RCA connectors, again with Deoxit. Tried several different input devices (receiver, CD player, iPod) with no good results. Is there something I have missed, or a further step that can be taken to diagnose the problem? Thanks in advance. Ron B.