Hi all, this is my first post on this message board.
I'm having the same problem on my 94 3000GT. I hooked a volt meter up to the power lead going to the player and had some interesting results:
With the car off, I'm reading 12.3volts. If I turn the dome lamp on or depress the break, the player shuts off momemtarly while the voltage stays a constant 12.3volts. Now if I turn the head lights on the voltage will drop down to 11.8volts, but the player is unaffected. I'm thinking this is amperage issue. I'm going to try tapping into the fues box, or somewhere else to get my switched power. I'll post if it works.