Donkey Kong graphics going crazy - where to start?

ArchNorway

Active member
Joined
Oct 10, 2012
Messages
247
Reaction score
59
Location
Oslo, Oslo, Norway
Hi,

I was playing my newly aquired Donkey Kong pcb yesterday, and just as I was thinking that "I love this game, I hope it never fails on me!" - it started glitching out. It started with one top to bottom black line on Mario when he ran over a certain spot, but in minutes most of the sprites on the screen looked as if they were going through a shredder. :( The scenario looks nothing like the example screens of http://www.brasington.org/arcade/tech/dk/ and I really don't know where to start with this. Any input and suggestions much appreciated! :D

It looks like this:
https://www.youtube.com/watch?v=A6fSnLInXCo
 
Last edited:
Hi,

I was playing my newly aquired Donkey Kong pcb yesterday, and just as I was thinking that "I love this game, I hope it never fails on me!" - it started glitching out. It started with one top to bottom black line on Mario when he ran over a certain spot, but in minutes most of the sprites on the screen looked as if they were going through a shredder. :( The scenario looks nothing like the example screens of http://www.brasington.org/arcade/tech/dk/ and I really don't know where to start with this. Any input and suggestions much appreciated! :D

It looks like this:
https://www.youtube.com/watch?v=A6fSnLInXCo

Step 1 is always check your voltages. If those are good, then I would reseat all the socketed chips.

After that, if it's still having the same issue, I would break out the logic probe and start checking at 1F, 1E on the CPU board and 3M, 3L on the Video board and work backwards from there.

The RAM at 2E or 2F could be messed up, but I doubt it.
 
Last edited:
Hi,

I was playing my newly aquired Donkey Kong pcb yesterday, and just as I was thinking that "I love this game, I hope it never fails on me!" - it started glitching out. It started with one top to bottom black line on Mario when he ran over a certain spot, but in minutes most of the sprites on the screen looked as if they were going through a shredder. :( The scenario looks nothing like the example screens of http://www.brasington.org/arcade/tech/dk/ and I really don't know where to start with this. Any input and suggestions much appreciated! :D

It looks like this:
https://www.youtube.com/watch?v=A6fSnLInXCo

I'm no expert but I'm debugging my DK and DKJr boards right now with similar issues, thought I'd pass along my experience.

+1 to check voltages. DK has ECL logic that uses -5V so make sure to check that. My switcher has adjustable +5 but not -5, and the -5V is off a bit. I don't get the feeling it's very sensitive but it's worth checking.

Does the behavior change if you leave the game on? Mine has glitchy sprites cold, but after it warms up it's nearly 100% perfect. The DKJr is more obvious in this regard than the DK, but they both do it. In my case once I figured that out I could then freeze spray suspect chips to try and find one that is sensitive to temp.

It happens on both my boards cooling the 10105 ECL NOR gate at 1F on the video board garbles the sprites significantly. Cooling the other ECL in that area doesn't do anything. I think it's suspect that *both* boards have the exact same problem so it may be a red herring but I'll replace it on the DKJr (the more sensitive of the two) and see if that fixes it. If not, I'll keep looking!

Also OneCircuit on YouTube has a series of DK troubleshooting vids that are pretty good. He has a lot of test equipment most of us don't have, but he points out what parts of the schematic do what, and I think he may have debugged a missing or glitchy sprite problem.
 
Thank you so much for the replies, guys! I am traveling with work at the moment, but I will be able to start tinkering with this over the weekend. I will let you know how it fares.

I forgot to mention, I have the Braze HS kit installed, and it does not come up with any errors when booting. As for voltages, I have gone the Arcadeshop route with the switcher and the conversion kit - just to avoid any future problems with the native PSU. What an irony if it turns out that it is the conversion kit that messes things up. :p

When booting, the game works fine. Once I coin up and start playing, the glitching starts after I have climbed one or two ladders.

Anyway, I will make good use of your tips while troubleshooting, and I'll come back to this thread when I'm done.
 
Hey OP, any updates? i finally got my 10105s, swapped one into my DKjr and... it didn't work. :( In fact it was worse.

Since MikesArcade.com mentions the 10125 level translator and since it's right next to and driven by the 10105, I figured that was the next sensible place to try. Swapped that out and my DKjr is now perfect!

My DK glitches were a lot more subtle and lately they've almost disappeared entirely. The weather has been warmer so the board starts warmer. Anyway I decided to swap the 10125 on that one as well. I ended up lifting a trace on the backside that I had to jumper, but other than that it went OK. Playing before hand I only noticed 1 tiny glitch, and afterwards I don't see any so I presume DK is now 100% too.

Interestingly the existing 10125 on my DK basically disintegrated when I started clipping the legs off. When I clipped the first leg the top popped off, exposing the chip inside. Then as I clipped subsequent legs the package around the chip just crumbled and split, spraying debris everywhere every time I cut. That's a ceramic package and evidently just got really brittle over time.

tl;dr --> Trying swapping the 10125. ;)
 
Back
Top Bottom