JoeB1355
Well-known member
This board is a total pita -- I had posted when I had stretched video problem, that was bad madsel 74ls163 -- replaced the board was good for a few days
then its crapped out again just flickered static -- bad wdog disbale replaced 74ls42 chip
So now it runs but no left track ball action it just goes right whether you spin left or right. It ends up being a bad 74ls74 chip
All good for 3 more days....
Now its bad again. Looks to me like there are 4 quadrants and at least 4 columns in each quadrant and my data just keeps getting rendered in the first column of each quadrant. All data appears to exist just gets jammed in the same spot... Not any good theory of operation in the MC manual that I found...
I've been tracking signals around but can really find anything missing. Anyone have any clues?
I haven't found any stuck data lines or address lines. Its like a clock that should cycle the columns in a quadrant doesn't count. Yet looking through the schematic it doesn't seem obvious to me and anything I think might be it seems to have activity with the logic probe.
I posted a video here:
http://youtu.be/kvpK3ESMnzY
then its crapped out again just flickered static -- bad wdog disbale replaced 74ls42 chip
So now it runs but no left track ball action it just goes right whether you spin left or right. It ends up being a bad 74ls74 chip
All good for 3 more days....
Now its bad again. Looks to me like there are 4 quadrants and at least 4 columns in each quadrant and my data just keeps getting rendered in the first column of each quadrant. All data appears to exist just gets jammed in the same spot... Not any good theory of operation in the MC manual that I found...
I've been tracking signals around but can really find anything missing. Anyone have any clues?
I haven't found any stuck data lines or address lines. Its like a clock that should cycle the columns in a quadrant doesn't count. Yet looking through the schematic it doesn't seem obvious to me and anything I think might be it seems to have activity with the logic probe.
I posted a video here:
http://youtu.be/kvpK3ESMnzY
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