Donkey Kong graphics issue

the11thdoctor

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I have a dedicated Donkey Kong that I just updated to JAMMA via the Mike's Arcade Nintendo to JAMMA adapter. I didn't have a way to test board until I got adapter. Cabinet is rewired and setup. I powered her up and it appears that there are double images. Not ghost images but as if the screen is split in half and on each half is the exact same image. Any ideas? I will try to post pictures later today if I can.
 
But is it the full height image compressed and shown twice or is it only half the screen displayed twice? I am not familiar enough with DK to know the difference.
 
Oh great. I can do simple repairs but I have no idea how to do something like that. Anybody have an idea of where to start? Is is it a matter of de-soldering a chip and replacing it?
 
Do you have a logic probe and the knowledge to read schematics?

Do you have the tools and skills necessary to desolder chips without damaging the board?
 
I can repair a board. I have done it before but that is because I was able to find online what to replace. I am not 100% comfortiable trying to read schematics nor do I own a logic probe. I am just a casual arcade game collector who can do some repairs if I am pointed in the right direction.
 
Grab the schematics here (this is the best version I could find):

http://archive.org/download/donkeykongjrschematicsjapan/Donkey_Kong_JR_Schematics_-Japan.pdf

I know it's DK JR, but for your problem it should work. Go to the 3rd page, area A & B horizontal and 10 & 11 vertical. The 74S161/163 at 1L, pin 14 puts out signal 256H. Either the signal coming from this pin is bad or the signal passes through another device that is bad.

I would recommend that you get a logic probe with audio output (http://www.amazon.com/Elenco-Electr...1_fkmr0_1?ie=UTF8&qid=1334256741&sr=8-1-fkmr0) and figure out where the signal goes bad.
 
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