Donkey Kong "glitchy pies" problem

[lifereboot]

Just wondering if anyone has ever seen this problem, and knows the cause/solution.  My game plays fine except for the pie factory stage, where sometimes pies display "glitchy" and flash in two places at once.  Makes the stage almost impossible to play because I don't know where the pies are truly located.

Pics are in this album: http://imgur.com/a/nWKZ1

I've taken my board to another player's home, put my board in his DK machine, and the problem didn't happen.  It makes me think it's a power issue, not a board/chip issue.

-Shaun

[marinomitch13]

Hmm, I've seen a thread about how to fix this somewhere on the net. I think it had to do with corrupted roms or something similar... lemme see if I can find it again.

EDIT: Haha! it turns out that those were your posts on KLOV and Reddit. I would side with the suggestion of the one KLOVer that said to just buy new roms. Odds are that it is just some sort of faulty code and not a monitor or connection issue. If it were a connection issue with the pegs of the roms not contacting the sockets properly, it may just be one little peg on one of the roms -which would be tough to find.

On the offhand that you haven't seen this already (I'm sure you have though), it's likely a bad 2716 eprom that governs the moving objects sprites, and you can find which eprom it is, depending on your board set, here: http://www.brasington.org/arcade/tech/dk/

2nd EDIT: I realize that I misread your post. You said that it *didn't* happen on another machine... in that case, check the voltage, like Ken said.

[Scoundrl]

*IF* the board really works 100% in another machine and not in yours the problem is likely low +5 voltage in your machine or a bad connector. I see you tested the voltages on the connectors and not on the board itself under load. My experience tells me that DK boards will often draw down more than .2 volts under load. It also tells me that DK usually runs fine down to as low as 4.8v.

My suggestion would be first, pull and clean the legs on the chips at 7C - 7F. If that does not fix it, test the voltages on the board at the edge connector while it is powered on. BE CAREFUL not to short two pins together. The pinout for the edge connector is here... http://www.mikesarcade.com/cgi-bin/spies.cgi?action=url&type=pinout&page=Nintendo_Classic.html

report back what you have for +5v and -5v

-Ken

[Monstabonza]

Hi, not really an answer but jeff how about a DK trouble shooting area on the forum??

[ChrisP]

Seems fair.

I mean, if there's gonna be an entire subforum for Big Kong...

[lifereboot]

report back what you have for +5v and -5v

5.01
-5.23

[lifereboot]

Today I noticed that pies start glitching exactly when the 5th fireball comes out of the oil can.

[lifereboot]

Attempts towards resolution:

Unplugged machine for a day, dismantled power supply, sprayed electronics cleaner in connectors and wires, let dry, reassembled (no change)

Removed and cleaned all socketed chips using a pencil eraser (no change)

Confirmed +5V and -5V at edge connector when the board was powered on

Observed the appearance of glitchy pies wasn't random, but always occurred after 5th fireball appeared

Removed and cleaned 7C - 7F chips on VIDEO board, this time using a wire brush dremel attachment and electronics cleaner (no change)

Sprayed electronics cleaner into and around power connectors on both boards, wipe clean with q-tips, blow dry with cool hair dryer (FIXED)

Once I realized that I could quickly confirm the problem by waiting until the 5th fireball came out, and seeing if the pies stayed normal or began glitching, it was simply a matter of trying things until something worked.  The ends of the pins in the cables and power connectors on the PCBs looked slightly blackened or "rusty" since I last had the glitchy pies a year ago.  The electronics cleaner made them silvery again.

Hope the pies don't come back again for a while -- but if they do, I should know how to correct it right away.

WARNING: electronics cleaner is flammable, if you're using it make sure it dries completely before supplying power to your PCBs, or risk their lives!

Cheers

Oh and here's the old KLOV thread when I had the same problem over a year ago http://forums.arcade-museum.com/showthread.php?t=211031

[ChrisP]

Hmm... so the fifth fireball causes this issue?

Almost sounds like a memory problem.

Too bad there's no easy way to diagnose your RAM chips without one of the Braze kits (which check them on boot). Maybe the problem is there somehow?

But if it's working, it's working...

[Scoundrl]

Too bad there's no easy way to diagnose your RAM chips without one of the Braze kits (which check them on boot). Maybe the problem is there somehow?

Just FYI the braze kit test are a nice start but i have seen them give false positives for bad ram and well as seen bad ram get past the test.

I'm glad you found a solution. I would have suggested checking voltage at a ram chip in the video board but giving that advice always scares me because it so easy to short things out. lad you are rolling again.

-Ken

[JNugent]

So Shaun, does this mean we'll be seeing 1.1M from you soon? 

[mikegmi2]

Nice, glad you figured out the problem!

[marinomitch13]

Glad you were able to solve your problem with the 'glitchy glaphics' -as Vincent would call them. #slenderkongjargon

[lifereboot]

I'm also glad to be rolling again.  Thanks everyone for your input.

So Shaun, does this mean we'll be seeing 1.1M from you soon? 

No promises.

[LMDAVE]

WARNING: electronics cleaner is flammable, if you're using it make sure it dries completely before supplying power to your PCBs, or risk their lives!

Oh yeah! That stuff is the most flammable product I've worked with. When I got my Defender machine I was doing a major cleanup on the power supply but was so anxious to try it afterwards.....didn't wait enough time, and the whole power supply block went up in flames. Scared my wife to death that whenever I pull out that can to do anything she starts yelling at me.