hi
I appened to salvage a pioneer pl221z from dumpster diving, and I initialy tought the power supply was removed, then I found the manual.
Indeed the turntable is designed to be powered by the black jack 12Volt plunged into the amp. Sin I have another amp, I tried to power if directly from a generic 12V DC adaptator.
It worked fine for me but beware the +12V should be connected to the outer ring of the jack, and the ground goes to the central pin. You must connect that ground pin to your amp pin too otherwise you will ged a loud hum.
The reason why I tought the power supply had been removed by the previous owner is that the case is designed to receive an internal power supply and there is also a hole for the 220V cord to get out.
So I think I am going to modify the turntable in order to install my PS inside with a 220V cord, and remove the jack to replace it with a mose standard ground terminal.
The position of the arm in the automatic start mode was not good. I found that there is a screw to turn in order to ajust this, in the vertical hole next to the base of the arm, on its left.