Donkey Kong picture goes off after a couple hours

enjoyvelvet

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My Donkey Kong monitor works fine but after a couple hours the screen goes scrambled and looks like the following picture.

The monitor looks fine except for the left side being cutoff and I know it needs a cap kit because of that. Is this just an issue that will be fixed with a cap kit or is something getting too hot? Possible board issue?
 

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My Donkey Kong monitor works fine but after a couple hours the screen goes scrambled and looks like the following picture.

The monitor looks fine except for the left side being cutoff and I know it needs a cap kit because of that. Is this just an issue that will be fixed with a cap kit or is something getting too hot? Possible board issue?

You are losing synch. You can try adjusting the Hhold pot on the chassis. There is another hold pot 3 inches behind the flyback you can also adjust. If neither of those keep the synch for long, cap the monitor of course, but you may also have an issue with the H and V centering pots on the board set. They may need cleaned or replaced. Bob Roberts sells them.
 
You are losing synch. You can try adjusting the Hhold pot on the chassis. There is another hold pot 3 inches behind the flyback you can also adjust. If neither of those keep the synch for long, cap the monitor of course, but you may also have an issue with the H and V centering pots on the board set. They may need cleaned or replaced. Bob Roberts sells them.

the H and V centering pots on the board set , do you know what number they are ?

I've given a cap kit to my DK Jr and it will still lose sync every now and then . Also the screen likes to move around a tiny bit when I'm playing .
 
the H and V centering pots on the board set , do you know what number they are ?

I've given a cap kit to my DK Jr and it will still lose sync every now and then . Also the screen likes to move around a tiny bit when I'm playing .

Nope, don't know the number. Since the left side is already cut off I'm sure a cap kit will resolve all the monitor problems hopefully...I just wanted to be sure this was probably an issue that could prob be fixed via cap kit.
 
I had this problem, installed a delux cap kit from bob roberts, and replaced the adjustment pots on the adjustment board from bob as well and this problem never came back.
 
I had this problem, installed a delux cap kit from bob roberts, and replaced the adjustment pots on the adjustment board from bob as well and this problem never came back.

I installed a delux cap kit from Bob Roberts also , but didn't replace the adjustment pots . I've been wondering if thats what I need to do to fix it .
 
Ok cool. I'm planning on taking it to Riptor to get capped. I bought the deluxe kit already but haven't bought the adjustment pots. I guess I will pick them up. are they generic or are there specific ones?
 
the H and V centering pots on the board set , do you know what number they are ?

I've given a cap kit to my DK Jr and it will still lose sync every now and then . Also the screen likes to move around a tiny bit when I'm playing .

What do you mean by "number"?
if you mean value, 30K or 50K will work. (I prefer 50K)
if you mean reference designator (location), they are VR1 up/down VR2 left/right.
These are the only two pots on the video PCB
there is also an H center pot on the remote board which is the center pot of the five.
Greg
 
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I found the post I made about this problem when I had it happen if you wanna have a look.

http://forum.arcadecontrols.com/index.php?topic=91835.0

It was reccomended that the cause was a pot on the control board and to recap it while I had it tore apart. I'm pretty sure the pot was the problem and not the caps, but like what was reccomended to me, I would suggest doing it while you have it out, if it hasnt been capped already. The pot kit is seperate from the cap kit scumbum, so you might want to try replacing those if you are still loosing sync, and that screen shake should go away too if it is the type where the entire image shakes, and not the type where part of the screen will move up and down when sprites move across it. I still havent got that fixed, but it is so rare that I am just going to live with it.
 
the H and V centering pots on the board set , do you know what number they are ?

I've given a cap kit to my DK Jr and it will still lose sync every now and then . Also the screen likes to move around a tiny bit when I'm playing .

Does your image move sorta like this?

Personally I installed Bob Roberts regular cap kit, changed the board pots (replacing the 30ks with 50ks), and I still have this problem. Whatever my problem it is it's not contained in a standard cap kit.

In order to resolve this problem, I just ordered a shitload of caps off mouser which should be here in a day or two. Once I get the caps in I'm going to do the following in an attempt to fix this.

1st I'm going to recap one of the big ones on the monitor not included in cap kits- C606 (at the advice of Dokert). I will also replace all the pots and a few more caps as well not included in Bobs Sanyo Kits, while I have the monitor pulled. If I fire it up and it still continues, I'm moving on to recapping the entire power supply. I should have a thread up by sometime this weekend (or earlier) reporting what I find and what exactly I did.

I assume my problem is related to h or v hold, because I can adjust away the problem for 30 minutes or so before it happens again. I suspect it's drifting ever so slightly. It seems there are a few other people on the board with the exact same problem.
 
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Glad to hear you ordered your caps to try and fix the problem mhanlen1, keep us posted on what you discover.
 
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