I know this is an older CD player, had it since new. The CD tray won't stay shut when its powered up. Popped the case, didn't see anything broken or ground off. Any ideas on where to start?
Underneath the tray you will find a so called end-switch.
Most likely you will need to disassemble the tray. I had luck in the past with some contact spray but best is to replace it.
The switch seemed to be tied to a rotary gear. I cleaned and tested the switch, made no difference. I even tried to ground out the connection manually and the cd tray didn't respond. Could possible be something a little bit more significant.