Just got a "new to me" D501. The unit powers on, but the tray mechanism is dead. At first I thought it may be a belt issue, but there is ZERO life coming from the motor, doesn't even try to spin. I pulled the clamping assembly out and removed the belt, still not even attempting to move. All of the caps look fine and everything moves easily when manually spinning the gears. It just doesnt want to do anything on its own.

The only sign of life when powered on is the main display. There are absolutely no signs of life inside the chassis, no movement, no sounds, nothing. It recognizes button presses for disc side and direct cd, but only by showing the indicator light. Nothing happens internally.

Before I go through and pull out the loading motor and test it, is there anything else I should be looking for? Maybe a limit switch or something?

Are you sure the laser pick up is connected up properly back to the main board?

I think that if it was disconnected, nothing would work because the player needs to know the laser is active to scan the disc prior to any other activity.

I would look for cracks and nicks in the ribbons cables as well.

The laser does need to be in the proper rest position before the unit will open or close the tray and yes there are sensor switches for this. With the unit off push the laser toward the back of the unit and power it on. If the laser does not move into rest position when you power the unit on you have more serious issues.

Tried that, absolutely no movement whatsoever.

So far I havent seen anything that immediately stands out. Ill have to toss a multimeter on it to see if there are any internal breaks.