I recently got given a STR 7055a in cosmetically good shape. It has good sound on the right but very weak (controllable by the volume knob) sound on the left channel. Cleaned, deoxidised, the balance when turned is still only a weak sound on the left side. no obviously bad controls. Going through the control knobs right to left I found: function: ok stereo: not ok- L, R, reverse: no effect, same , good sound on right side only. filter: ok treble: right full effect, left little or none (weak sound, hard to tell) bass: same speaker A/B/C all weak on left. suggestions? I do not see anything obvious like trace cracks, bad joints, etc. if i put it all the way to left, it has weak controlled volume. Any suggestions before i save the knobs????? Edit: I'd like to fix it if possible, anyone got any suggestions?