I'm trying to fault find an asteroids board with Read/Write Problems
on the vector RAM.
So far I've done the following:
The game arrived with no display and two tones indicating E2/E2 RAM
Fault; I quickly traced the fault to M5 pin 11 being stuck low so
the RAM was never selected.
Now the game gives two high tones and two low tones. When using my
Fluke 9010A I am getting a R/W error on bits FF for all addresses in
the range 4000 to 47FF. The vector ROM however gives the correct
checksum (CBED) so the buses must be OK?
Does anyone have any idea where I can go from here?
--
Dave Langley
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Received on Sun Jan 23 03:30:40 2011