Could be any, the diag does not tell us which bit(s) are bad. Go to MONITOR and put some 00, FF, 55 and AA bytes into the F900 area to see which bits are stuck or crossed. Use the flag at 7F8 to get RAM if necessary (put 00 or 80).
Could be any, the diag does not tell us which bit(s) are bad. Go to MONITOR and put some 00, FF, 55 and AA bytes into the F900 area to see which bits are stuck or crossed. Use the flag at 7F8 to get RAM if necessary (put 00 or 80).