Sounds like the CPU is not executing the code properly, or is getting
stuck somewhere waiting for something to happen. I am not familiar with the
structure of the code, but sometimes panel scanning is initiated by an interrupt
to the CPU. Maybe check any external interrupt signals to see if they are pulsing?

Sometimes you can check address decodes and get a feel for whether the CPU
is stuck polling one particular device, waiting for something to happen.

Also, if you have some spare RAM chips, try temporarily replacing them to see
if that changes anything. A bad RAM will prevent proper CPU execution.
Since the Polaris can use two different sizes of RAM chips, you can infer
the minimum amount of RAM needed for it to operate, and only install that much,
then try different chips.

Of course Paul D is the expert on all things Polaris...

Bob