Error 16 - Caused by DVD Drive?

I have 2 xboxes.
xbox A" is Hungarian modded v1.0 (I believe Softmod, as no additional wires on top of motherboard. But XBMC lists a mod chip.); however, it's Thomson TGM600 DVD drive no longer reads discs.

xbox "B" is Mexican v1.0; however, it displayed Error 16 and it's Power and Eject buttons do not behave as intended.
It powers on as soon as it is plugged in. It will restart upon pressing eject. It will eject if you hold down the eject button, but will restart when you press the button to insert the disc. It's DVD drive is Philips VAD6011/21.

I swapped the DVD drives and had interesting results:
xbox "A" displayed the xbox logo but did not display "microsoft."
xbox "B" now booted and set the clock, then restarted reliably; however, it's buttons were still wrong.

Is there something wrong with the Philips VAD6011 drive, or is this a compatability issue?

Also, does anyone know where I can find a list of the dvd drives that came installed in original xboxes?


All input appreciated. Thanks!