Hmm, okay. Maybe there is still some reason for hope
I almost wonder whether the equalizer is really still fine in this case, because I thought I noticed that the radio display was acting "funny" (it's only really noticeable when it's dark). The radio LED display appears to be alternately displaying either the time, an FM station, or the FM station and the tape status display. So, something strange is going on here, and I'm almost wondering whether if the radio/tape interlock is somehow hung up, and is preventing the tape audio output from disengaging and allowing the radio audio output to kick-in (in the past, I've noticed that there's "delay" in the switchover to the radio when you eject a tape). This is all mostly conjecture (and maybe with a hint of wishful thinking . . .). Am I barking up a dead tree?