Donkey Kong video issue

[johnrt]

Hi!

I'm a long time follower of the John's Arcade youtube channel! :-) I'm located in Norway. I have built a DK cabinet from scratch and have aquired 2 DK boards from the US.

So to the problem: I'm having an issue with one of them. I have some small glitches on the screen. They seem to appear only on the left half of the screen. I have isolated the issue to the video board. I swapped the boards from my fully working one. I have also ruled out the ROMs. The PCB plays normally apart from these glitches. So does anyone know what's going on here? I have a video showing it here:
https://www.youtube.com/watch?v=ar58yV3aQag

Btw: Here's a video of my homemade DK cabinet:
https://www.youtube.com/watch?v=MUQDk4dkLts

I appreciate any help I can get. Have a nice day.

--
John Roger

[Techie]

I have not dealt with this issue directly on .  These issues are sometimes difficult to pinpoint.

Mike's Arcade repair log mentions the following:

03/21/2002

Problem: Sparklies or Graphic glitches.

This is a pretty common problem on DKjr and DK boards, but this is the first time I've found a cure.
This particular board was fine until I let it run about 1/2 hour. I had upgraded it to DDK and when testing it as a Jr board saw no problems, but didn't' let it run too long before I upgraded it.

After the upgrade, I let it sit and burn-in while I went to eat dinner. When I came back, the top or the screen above Polly screaming help in DK was filled with glitches! I booted over to DKJr and the key on the top exhibited the same problem with sparkly glitches. So, I grabbed a can of freeze spray. All the ECLs were really hot to the touch, so I hit them one at a time, then watched the screen. The faulty chips was a MC10124 at 4H, this chip is a quad TTL->MECL translator. The MC10125 is it's counter-part and goes from MECL->TTL.

After letting it run another 1/2 hour or so, in DK mode I noticed just a few sparklies at the top, under the high score. So I shot the MC10125 at 4F with freeze spray and watched for more sparklies. As long as I shot the chip every couple of seconds, the sparklies didn't show up. If I waited a few minutes, they would again appear. Changing both chips solved the sparkly problem with this board.

Solution: 2 bad ECL translators, an MC10124 at 4H and the MC10125 at 4F.

https://www.mikesarcade.com/arcade/repairs/dkjr.html

[beerNpretzels]

I had a very similar problem on my dkjr and dk pcbs.  Fixed both by replacing the 10125s on the video board.  They're available on ebay.

[johnrt]

Thanks guys! I was actually suspecting those myself. These are among the IC's on the board that gets hot, and therefore may fail after some years. I've ordered a few of both 10124 and 10125's. I'll let you know if that fixes the problem.

[johnrt]

Solution: 2 bad ECL translators, an MC10124 at 4H and the MC10125 at 4F.

That solved my issue. I changed the MC10125 at 4F and the glitches are now gone! I ordered both some 10124 and 10125, but the problem went away after the first chip I changed. So I didn't bother changing all of them. It has now been running flawlessly for about an hour and it still runs fine!

https://www.youtube.com/watch?v=lxAwUYxm0so

Thank you for leading me in the right direction!