Reset rip board

I have a Lexmark T640 which is stuck in a never ending reset after power up. Is there a method of swapping mainboard electronics which have been previously installed in other machines for troubleshooting (used RIP or controllers)? It seems that there is a signature tag created on these cards at first installation, and renders these items useless when trying to swap-out to other machines.

Is there a known work-around or reset utility available?

In this particular case, I have replaced the power supply and fuser (when fuser is unplugged AC Mains or Thermistor)and it induces an error condition which throws it out of the reset loop. So this sounds like a logic error.

Lexmark tech support has indicated that we cannot part-swap these boards.

There must be some type of work-around....