Tech - Super Pac-Man constantly goes up (confirmed bad cap..

[Guest]

Archived from groups: rec.games.video.arcade.collecting (More info?)

I was testing a Super Pac board and once coined up and started, Pac only
goes up and wont go any other directions.

I tested the caps between the input lines and the chip and only the UP cap
was open (no resistance drop from infinite to ~100 ohm and back to infinite
when touched).

Previously I had fixed a Pac board with this problem by simply lifting the
cap and not replacing it, but lifting it didn't work on this board, it still
went up.

So does it need a new cap, or is the input chip(s) fried? Any ideas?
Thanks.


Also: There is some pixel flashing in the fruit and keys on the demo and
main screen. Random but repetative across the entire screen on the same
type of objects at the same spot. Pac/Ghosts/Maze/Dots dont have the
problem. Bad video ram? Bad character prom/controller? Or too low
voltage/lack of sufficient grounding? (All was runing on a PC power supply
(switcher) on a test bench)

 

[Guest]

Archived from groups: rec.games.video.arcade.collecting (More info?)

You will probably find a bad input chip. Just swap it out. And the last
time I had noise associated with a dedicated section of screen graphics
it was a RAM that tested good in self test. Take a good 2114 ram and
star at the bottom of the row. Swap it in with the bottom one. If it
doesn't take it away, move onto the next and swap int he one you just
removed from the first one. Rinse, lather, repeat.

- Matt