Donkey Kong Jr Board problem. Picture Scrambled?

OIB1981

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http://www.youtube.com/watch?v=i1j3ahlF5K0

Here a video of what it's doing above. Could this be a Z80 problem? Think a new one will fix it?

It has a high pitch sound when you first boot it that stays with it while the game is on. When I restart the game I think you can hear it. When you see the side of the cab that me pulling the plug then plugging it back in so you can hear the sound start back up at that point.
 
Was it working fine then just started doing that? Hard to tell from your video, but it could be a sync issue? Doubt its a Z80 problem....
 
That is not an issue with the Z80, you can see the intro screen in the beginning of the video. If it was the Z80 you wouldn't be able to make out anything, it would just be garbled images, characters and numbers.

Try adjusting your sync and position pots on the back of the monitor, one of these could be damaged and be causing your issue. The monitor might also need a cap kit, from the video it looks like it is starting to have a wavy flag shape. Hope this helps.
 
Sigh - why is every monitor problem on this site diagnosed as "needing a cap kit". Car windscreen dirty? Try replacing the spark plugs! Headlights not working? Try replacing the spark plugs! Engine leaking oil? How about some new spark plugs....

/sarcasm

You have lost the video ground connection between the board and the monitor thats all. Depending on where this last worked, and where it is not working now its hard to say whether its your wiring that doesnt connect up the video ground as the board expects, or if the wiring has come loose in a cabinet, but if you have picture that is rolling or tearing, and you can roughy see a game running in the messed up image, and you have dark oily looking colours, then you are missing the video ground connection.

If it is torn up to the extent you can't make out anything and the colours are sharp then you have lost sync.

In your case its video ground that is AWOL, no capacitors involved in this fault.
 
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I got this board as a spare off ebay. My other board works fine so I don't think it's an monitor issue. I changed the flyback and did a cap kit on this one myself. Other board works with no issues.

Think the ground on the board came loose? The P10 connector looks a little stressed out to me.
 
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Its worth buzzing it through. When you say another board, do you mean another identical board, or just another game? Some games just tie video ground to system ground on the board, others have use a separate pin for it which may or may not be connected on your harness.
 
Well it is giving you the classic "no video ground" fault so that's where you need to start.
 
Sigh - why is every monitor problem on this site diagnosed as "needing a cap kit". Car windscreen dirty? Try replacing the spark plugs! Headlights not working? Try replacing the spark plugs! Engine leaking oil? How about some new spark plugs....

/sarcasm

You have lost the video ground connection between the board and the monitor thats all. Depending on where this last worked, and where it is not working now its hard to say whether its your wiring that doesnt connect up the video ground as the board expects, or if the wiring has come loose in a cabinet, but if you have picture that is rolling or tearing, and you can roughy see a game running in the messed up image, and you have dark oily looking colours, then you are missing the video ground connection.

If it is torn up to the extent you can't make out anything and the colours are sharp then you have lost sync.

In your case its video ground that is AWOL, no capacitors involved in this fault.

So what your saying is he needs a cap kit? :)

/sarcasm
 
Inspect the two pots on the video board for damage. Try adjusting them and see if it helps. It is common for these to get broken and can cause an issue that looks like bad sync.
 
You need to adjust the monitor for that boardset. You can't just slap a boardset in there and think it is going to come up just like the last boardset.

Your V Hold is off and your H Hold needs to be adjusted too.

You will have to make both adjustments to know if you have a ground problem with the monitor sync. I don't see anything wrong other than a couple of minor adjustments.
 
Like Dokert said, it often requires some minor adjustments when swapping boardsets. But being that pcb was just shipped I would be looking at the pots on the pcb. They were installed in a terrible spot and get alot of abuse when the boards are handled.
Also on the cap kit issue, most every sanyo monitor with original caps will need to be recapped. They are old and the caps have reached their life span. Some monitors have higher cap failure rate than others. The sanyos and GO7 are two that should always be recapped if they still have their original caps.
 
Riptor you are right. Before I looked at the forum I ran a few test on that P10 connector it seems to be good. Then I got to looking and the Pots are broken. One on the left has a leg broken on the left side. One on the right has leg broken on the right side. What kind of pots are these and where would I buy some so I can repair the board?
 
I had a DK Jr with a bad 3P and it put lines across the screen like that, but mine were much more pronounced. Not sure if it is the same issue but it is worth a shot.
 
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