> ... I have a Polaris that has seemingly seized
> up completely? Basically it powers on with about
> half the leds remaining lit...

Following up to the responses of others, this can also occur because of
the 'reset level' adjustment ("DC OK Threshhold") on the power supply
being incorrect.

Specifically, it could be a little low, causing the CPU to wake up
before it should. If this is the source of the problem, then it is
something easy to address (and is covered in the Service Manual, ref:
Section 6 - Adjustments and Checkout) [The service manual is available
in PDF form at
http://www.rhodeschroma.com/?id=polaris ]