Auto shut off not working

Or I should say, it works when it shouldn't (ProJect 2.1 Comfort tt).

At the start of an album, once the platter gets exactly up to speed, the auto shut off goes off (opto-electric circuit), and the table keeps spinning but the tone arm will not go down. When the shut off happens, the sound is like a spring snapping, a delicate little 'twang' sound...

I am able to repeat this over and over, twang twang twang, arm does not drop...anyone else experience this?

Debris or alignment issue maybe?
sounds like a solenoid or relay kicking in (the twanging sound).
Hey thx, yeah, relay or something sounds about right. I took things apart, got it working without knowing what I did, then it wouldn't work etc. Picking up my fathers unused mint Technics SL-Q3 shortly for nothing as a temp replacement so...