GBC 4250 No Power?

What happened:
Co-worker went to use the rear cutting blade to cut off excess laminate while the machine was in operation (rolling). I happened to be overseeing the project and watched as the unit simply powered down and will not power again. All plastic guards were in place, no sounds when it shut off and no smells.

Background:
This laminator has the feed tray sensor bypassed by the prior owner and we have had it working for about 5 years like that. I also ziptied the safety shield sensor so it was always on so I could open it about half-way during operation so the cams would actually apply more pressure to the heat rollers (which are ancient).

Things I have checked:
Continuity on rear fuse and internal fuse
Continuity/operation of the safety shield switch
Continuity/operation of the on/off switch
As far as I can tell the wiring is in flawless shape--and have checked several for continuity.
The two control boards appear to be in flawless condition--capacitors are good and used a loop to visually check both boards.

I have no idea how to check the heat sensors and/or the heating element, but I am not sure either of those can even cause this issue.

I assume the unit would power even if the motor burned out.