Galaga screen bars

dethfactor

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Finally got around to fixing a Galaga that played blind and had a suicidal k4900 to be welcomed to three strange gray bars on the screen. Cleaned up the ROMs to no avail, wondering if something got cooked. Any ideas? Is it the RAM going bad?

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Interesting. White picket fence behind the text? I assume it is also behind the sprites?

Doesn't look like a problem with the 6116 RAM on the CPU board but you could try swapping it out.
 
Interesting. White picket fence behind the text? I assume it is also behind the sprites?

Doesn't look like a problem with the 6116 RAM on the CPU board but you could try swapping it out.

Correct, the starfield/sprites display over it. They're just gray bars. So should I try swapping the 6116's? or do you think it could be a CPU?
 
I don't think it is a ram/rom/cpu problem, I think it is a connection problem. Try cleaning the edge connector with an eraser and verify +5 volts at about 5.15 and verify the rom programming.

Post a pic of the board also, I will bet this has the older resistor packs that cause problems.

re connect the ribbon cable a time or two.
 
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Hmmm... show a picture of what the game looks like while playing.

It's not a 6116 issue.
 
Got a video of the screen. Forgot to take pictures of the board, will do it tomorrow.

 
ok so I've gotten nowhere with these and picked up a few more boards that aren't helping me much. Here's a few more pictures, got the monitor working too. Any help would be great!

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I would verify the rom at 3j. There are several different rom files for that chip and it may not be the right one or version for that location.

I still think you have a connection problem with a trace or socket and that is where I would start. Look that board over very very well In full sunlight and note any marks on it. Then meter the traces to verify they are good. I don't really think it is a logic problem. The sockets have been replaced so you might look/meter them to make certain nothing is shorted usually happens under the socket so you really can't see the short.

Also check the sockets that have not been changed.
 
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