> ... My Chroma Polaris has developed a problem.
> On power up it freezes. ...

While there certainly would be many possible causes - this behaviour can
also occur because of the 'reset level' adjustment ("DC OK Threshhold")
on the power supply being incorrect (and this setting can change over
time, as the components in the power supply age).

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 . The section of
interest can be found at
http://www.rhodeschroma.com/?id=polarisserviceadjustmentscheckout#dcokthreshold ]

David Clarke