Pacman and monsters floating over maze.

Patnukem

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Was working fine the day before, then this. I have no Idea where I should start! any suggestions? one of the heat sinks on one of the chips did fall off a while ago but I doubt that is what did it.


IMAG0722 by patnukem1, on Flickr
 
Do they always stay in the bottom right 1/4 of the screen?

I had a board on my bench last week doing that and it was one of the 7489 bipolar RAMs.

RJ
 
yup, sometimes they pop up on the very top right just about a inch or so down then they go back up and end up at the bottom again.
 
Usually its either a 7489 or the ls161's right below them. There is also a LS283 and I think a 174 right next to it. Look around in that area and you will likely find the problem.
 
oops, I was touching up solder just to make sure it was not the culprit and now I have made it worse, now the maze is made of numbers covering the screen and there are some upside down blue cherries, Who knows what I did to it.
 
It's easy to bridge the solder joints to traces that run next to the solder pads. Pac Man and Galaga boards are both notoriously ugly boards to solder on. Look VERY close at the board for tiny shorts.
 
It's easy to bridge the solder joints to traces that run next to the solder pads. Pac Man and Galaga boards are both notoriously ugly boards to solder on. Look VERY close at the board for tiny shorts.


I think the galagas are much worse than a pac board. The traces run really close to the pads on them.
 
Was working fine the day before, then this. I have no Idea where I should start! any suggestions? one of the heat sinks on one of the chips did fall off a while ago but I doubt that is what did it.


IMAG0722 by patnukem1, on Flickr


Thats not a problem, thats a feature. You can charge much $$ as your version's ghosts actually go through walls!
 
well, got some parts boards to mess with and a bunch of the traces got messed up on my initial board (long story) so I have moved on to one of the parts boards, I replaced all the missing ic's on the board that were missing and it just boots with f's and the top and bottom of the screen no sounds, and none of the input seems to change it, any idea where this problem may be located?
 
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