GO7 has a slight rolling wave

pinnut

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got a ms pacman had a dead monitor. needed a flyback and hot. powered it up and got an image as seen in the pic, with the right side curling. it had a sticker said it was recapped in 2002. i recapped it with a kit from arcade parts and repair. some of the values in the kit were a little different than what was used in the org re-cap. i also replaced a broken width coil, it was just hot glued together. i also did the C303 mod as per the instructions, it had not been done. i now have a much better image, no curl. however, the colors look off, and there is a visable slow roll from right to left, and it distorts the image slightly as it rolls across.

any ideas? seems like a cap value might be off, but ive no clue where to start.

i also made a video, its a bit hard to see, but you can see the image distort.
https://youtu.be/60HdiHQyXJ8

thanks
 

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curling is horizontal hold. or in the case of the G07, it could be caused by not having the negative horizontal sync (pin 10) also bridged to the negative vertical sync pin (pin 9). Pac-Man came with them bridged cause they mostly came with G07s I guess. the others that came with Wells-Gardner monitors shouldn't be affected by the bridge I don't think, but they don't require it.

the bar going through the screen is the notorious Pac-Man hum bar. to save yourself a lot of future agony, I encourage replacing both fuse blocks (the one on the left will be the line and monitor fuses; the one on the right is for the fuses to the special transformer to generate 7V and 14V that are rectified at the game board to +5 and +12 DC) after that, I would reflow the rectifying diodes at the game board and clean the edge connector up the best you can with a pencil eraser. the factory fuse holders are ancient now and will create bottlenecks in the voltage feeds due to corrosion, which will turn into increased resistance, which turns into increased heat that can burn up your edge connector.

the new fuse holders to the isolation transformer should correct the hum bar issue.
 
what do you think about the colors, especially the upper left?

thanks
 
I can't tell, but I'm guessing it's a cocktail Ms. Pac. the gaussing effect (where it's magnetized) is influenced by the earth's poles. the poles being North-South, if you read monitor manuals you'll find they encourage facing the cabinet East-West to do any crazy final adjustments. :)

cocktail games have the tube sitting in a flat position, it's more influenced by the poles. the degaussing coil on the monitor should be enough to clear it up on its own, and you may have to rotate the cabinet 90 degrees for better results. the monitor coil only runs for so long though before the thermistor heats up and shuts it off. in order to use it again, you'll have to power the monitor down for 20-30 minutes.

or, as suggested, get the manual ring to clear it up. :p reminds me, I found the one at work in a really strange place on the shelf, I need to dig it out later before it vanishes.
 
i used an old tape degausser to do it, its quite heavy. man, that thing must put out some field, it was like an acid trip on the screen. it did help with the colors, but i still have to fix the roll.
 
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