That is 3 pairs of speaker outputs, CD,tuner and tapes ok. Left unused for a
few years.
Will check for amp noise on the speaker outlets in the next hour. At the
moment I'm thinking muting via corroded erroneous phones bypass switch ,
impossible to see /probe without taking all apart. Any other ideas to look
at. Looks like 2 stereo SIP hybrid amp packages, unlikely both failed, no
approprieate fuses seen yet.