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Subject: Re: [chromapolaris] frozen

From: Bob Grieb <bobgrieb@...>
Date: 2015-02-11

Sounds like the CPU is not running.    It may not be getting reset properly,
or maybe is held in reset.   Your code EPROM's may have lost some bits due
to bit rot, but it's probably something else.   You could try re-seating the RAM
and EPROM chips.   If you have a scope, check the reset and clock signals to the CPU,
and the chip select to the code EPROMs.   If you don't have a scope, re-seating the
memory chips (carefully) and checking the 5V logic supply might be worth doing.  Also,
you could verify that the CPU reset signal is not asserted.   There are a number of chips
that could stop the CPU from executing code properly.    Trying to troubleshoot it without
a scope will be challenging...

I guess it's possible that the CPU is writing that pattern out to the LED's before it stops
running, but it may also simply be how the chips that drive the LED's power up.   It's
possible that they don't get reset at power up, and the outputs are in a sort of random state.
Random, but repeatable for a particular chip.

A friend of mine had a Polaris that was in a similar state to yours.   We fixed it by swapping
out the CPU with one from a parts unit that he had.  Not saying your CPU is definitely bad.
That's just one reason the CPU may not be executing code properly.

   Bob 


From: "lou@... [chromapolaris]" <chromapolaris@yahoogroups.com>
To: chromapolaris@yahoogroups.com
Sent: Tuesday, February 10, 2015 9:50 PM
Subject: [chromapolaris] frozen



Hi everyone,
My Chroma Polaris has developed a problem.

On power up it freezes. LEDs light up as though it remembers the program but there is no response to button pressing or keys played. After power down and up again the exact same pattern appears.

Any suggestions?

Lou