Scrolling K4900 won't stop

bnetty

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Donor 2016
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Pleasant Grove, Utah
I just can't get the screen to stop scrolling. Usually vertically sometimes horizontally. I've adjusted the pots a billion times but when you get close they start heading the opposite direction.

I've also cleaned the connections with electronic cleaner but it didn't seem to help.

Ready for some more suggestions!

Video:
https://goo.gl/photos/MUPfPVauTFvA4gRM6

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Does it have sync polarity switches? That was the cause of this on one of my games.
 
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Sync wires are probably not in the correct spot, or incorrectly tied together for the game PCB. What game are you trying to sync?
 
verify the solder is good on the signal headers. if your vertical sync pin is cracked it'll just roll.

that's also probably a positive sync game but I don't know for absolute certain.
 
you needs the electrolytic capacitors replaced everywhere you can find them there on that board for the exception of that BIG one

reflow the header pins with new solder yes
 
if your sync is hooked to pin 3 correctly and you don't have cold solder joints on the header pins then definitely with those old caps replace them with a cap kit. here is the best quality kit for your chassis.
https://www.arcadepartsandrepair.co...s-gardner-k4900-series-cap-kit-105c-nichicon/

It looks like there's a few caps replaced but it'd just redo it all with security0001's kit (fantastic seller). Reflow solder around the headers and verify the sync connections are good on the board to the monitor. Do all that and report back :) edit: now that I'm thinking of it, you may want to buy new pots too for good measure, I'm sure security has them
 
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