Donkey Kong Video Board

Darryl1970

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Donor 3 years: 2013-2014, 2016
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I have a spare DK 2-board set. My main board is acting glitchy (Video board). I decided to swap the video board from my spare set.

The spare board seems to be pretty solid, aside from some horizontal (technically vertical) lines.

In case I get some spare time this weekend, does anybody have a good idea what component, on the VIDEO BOARD, might cause this?

I am assuming this wouldn't be an EPROM issue. I do not see anything on Mike's Arcade or Braze quite like this.

Throwing out a feeler for anybody who might be able to identify this.
 

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No ideas? I have no trouble replacing chips, if I know which one is probably bad.
 
Might be the ram between the video rom and the dac's for the rgb lines. Looks like the pcb is drawing lines every other frame when it should be reading.
 
Might be the ram between the video rom and the dac's for the rgb lines. Looks like the pcb is drawing lines every other frame when it should be reading.

Cool. Thanks. I am ordering a logic probe, so hoping I can start some actual troubleshooting. I have replaced some MC10124/MC10125 before, to fix graphic sparkling.. I have some spare 2114s.. I hope that's the RAM.. lol.
 
I have a spare DK 2-board set. My main board is acting glitchy (Video board). I decided to swap the video board from my spare set.

The spare board seems to be pretty solid, aside from some horizontal (technically vertical) lines.

That looks like it's tile related, as it's following the background tile colors and it's repeating every 8-pixels lines, so seems unlikely it's sprites. From the position it looks like the 6th pixel is stuck. So.. possibly a bad 2716 at 3P or 3N ( swap as you have another video board ), or bad 74LS299 shift register at 4P or 4H. Check for stuck bits on the LS299s inputs.
 
That looks like it's tile related, as it's following the background tile colors and it's repeating every 8-pixels lines, so seems unlikely it's sprites. From the position it looks like the 6th pixel is stuck. So.. possibly a bad 2716 at 3P or 3N ( swap as you have another video board ), or bad 74LS299 shift register at 4P or 4H. Check for stuck bits on the LS299s inputs.


Thanks! I can check and verify the 2716s with my EPROM burner. If that checks, I can check the 4P / 4H.

Below is a video of me switching from one DK board to a second (using a Vector-Labs switcher). I have 3 boards (DKII, DK Remix, and DK Jr.) I had a horrible picture when I tried stacking DKII and DK Remix.

My second DK (with Remix) was having an issue where the picture would be completely out of sync for about 10-15 seconds, upon first powering up. It was bad, like the attached image, for much longer. (What you'll see in the pre-re-seating video was like that in slow motion before.) It would slowly get into sync. It USED TO even have sprite sparkles in the white colors until it warmed up for about 2 minutes. Once warmed up, it sync'd instantly, and the sparkles went away.

attachment.php



I re-seated and cleaned some socketed chips. That has helped. The sparkles are completely gone. The sync issue is now barely noticeable.

I created a video of it, now that it's better. Any idea why it still takes about 3 seconds to sync. My other board doesn't do that.

Here's the video.
https://photos.app.goo.gl/GQB7B3lhHfvVhVn93

Thanks,
Darryl
 

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  • DKSync.PNG
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