Ms Pacman "Backwards" and fliped graphics

SYReal

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Ms Pacman "Backwards" and fliped graphics

Joined yesterday to help restore my Ms Pacman. The board powers up and passes self test. The display is flipped and text is backwards. I read in an old post that this may be due to a cold solder joint. I am going to pull the board and resolder it. Anyone know what joint I should start at? The screenshot shows the problem. Thanks Eric
 

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Joined yesterday to help restore my Ms Pacman. The board powers up and passes self test. The display is flipped and text is backwards. I read in an old post that this may be due to a cold solder joint. I am going to pull the board and resolder it. Anyone know what joint I should start at? The screenshot shows the problem. Thanks Eric

First off Welcome to klov

First thing to check would be your voltages on the ic chips and next simple thing to check would be the dip switches. You want to make sure they are not set for cocktail or something like that.
 
Thanks. I will do that. The dip switches appear correct. so the PS is next. Eric
 
Syreal, where are you located? You might find you're close to someone who has experience or at least a working machine to help you diagnose your problem.
 
that version was made for the 'acid' crowd. It looks normal with 5 hits in your system
 
Looks like an addressing issue is being caused by either 4E chip bad or 4D which is a 74ls273 (flip Flop) being bad try there first.
 
Looks like an addressing issue is being caused by either 4E chip bad or 4D which is a 74ls273 (flip Flop) being bad try there first.

Thanks everyone. I am in Scotttsdale, AZ. I am trying to free up some time to get into it. Spent the last day touching up my roached cabinet. I picked the game up for $80 and am trying to keep it a low cost restoration. Found a paint at Home Depot that was sort of close.

Eric
 

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Behr Riviera Paradise is close but needs a bit more green.
 
Looks like an addressing issue is being caused by either 4E chip bad or 4D which is a 74ls273 (flip Flop) being bad try there first.

Inspected 4E and 4d both visually appear ok. No noticeable shorts or bad solder joints. I ordered a replacement 273 and should be able to swap them soon

From http://lawnmowerman.rotheblog.com/

"Plays, but Pac/Ms. Pac and all the monsters go through the maze upside-down! All other graphics are okay. Pac and the monsters look like they're upside down.

Bad 74LS157 at location 4E, pin 9. This chip is a quad, dual-input multiplexer. The "FLIP" signal, activated when the board is in cocktail mode, flips over all video signals during Player Two and this chip was not selecting its inputs correctly. "FLIP" was getting through in this channel when it should not have been. Replacing this chip cured the problem. (Thanks Matt McCullar)"
 
Thanks everyone. I am in Scotttsdale, AZ. I am trying to free up some time to get into it. Spent the last day touching up my roached cabinet. I picked the game up for $80 and am trying to keep it a low cost restoration. Found a paint at Home Depot that was sort of close.

Eric

Glidden Evermore Rhapsody is your sure. Get some of that.
 
Thanks everyone. I am in Scotttsdale, AZ. I am trying to free up some time to get into it. Spent the last day touching up my roached cabinet. I picked the game up for $80 and am trying to keep it a low cost restoration. Found a paint at Home Depot that was sort of close.

Eric

Put some hot peppers in the bottom of that cab or around and that will take care of most of your problems with mice, ants, snakes,etc. I am not sure about roaches.
 
Put some hot peppers in the bottom of that cab or around and that will take care of most of your problems with mice, ants, snakes,etc. I am not sure about roaches.

Ha well I guess I need clarify. I meant roached as in "bad shape" No insects just appears that it was stored outside for quite some time. When I store a car I put Irish Spring soap bars on top of each tire. Keeps Mice from getting in the car. They hate that fresh scent
 
Ha well I guess I need clarify. I meant roached as in "bad shape" No insects just appears that it was stored outside for quite some time. When I store a car I put Irish Spring soap bars on top of each tire. Keeps Mice from getting in the car. They hate that fresh scent

I never heard that and have a new weapon against Mice. I hate u mices to pices.
 
Here is how it sits today. after installing a new/old joystick (the original pacman one was gone :( ) I am able to confirm that the Ms Pacman, the ghosts and the fruit all appear to work as they should. The maze dots are inverted and mirrored. In other words if Ms Pacman gets the lower left power up the upper right power up goes away. so sounds like there are a couple problems. I am going to swap the 74ls157 first (4e) Is there any bennefit to soldering in a socket instead of direct sodering the IC? Do these go bad often? Thanks Eric
 

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TTL IC's are pretty reliable but it's good practice to solder in a socket for a few reasons:

- The new chip could be faulty.
- If you are inexperienced you may kill the chip with too much heat when soldering it in.
- To make future repairs/diagnosis much easier.
 
Hew, Thats what I was thinking. I am pretty sure of my soldering skills, but my hand isnt as steady as it used to be. Eric
 
Ok I swapped 4E and 4D and it did not change at all. Still mirrored words and scrambled maze.

Any other ideas?

I was able to get sockets and solder them in. Found it was much easier to cut the old ICs out and then clean up the joints.
 

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Some additional pictures of the flip flop mirror double reverse problem.
 

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