Donkey Kong Character ROM issue

Darth Vader

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I have a 4 board Donkey Kong PCB that is having an issue. The playfield and game functions fine and looks perfect however, Mario, Donkey Kong the barrels and the princess on the top are completely missing. (they are invisible) My guess is this is a bad eprom and that is all. Anyone know who burns new roms out there for this?

Anyone else had this same issue and can ID the correct eprom on the boardset.

Any help would be appreciated. Thanks!
 
My 5b was bad and did a similar thing. I bought an eraser and programer. If ya want to send me your roms, i can check them out and see if they are all right. If not i could identify the bad one and see if it can be rewritten. Barring that you would need to order another chip and have it written.
 
My 5b was bad and did a similar thing. I bought an eraser and programer. If ya want to send me your roms, i can check them out and see if they are all right. If not i could identify the bad one and see if it can be rewritten. Barring that you would need to order another chip and have it written.


Thanks for the information. I have someone local who can burn the chip, I think so I should be good there, more than anything I needed the location of the chip......so thanks for the help. I'll check that out on my PCB this weekend.
 
Well. I bought a high score kit so I could test the roms on-screen. They pass the test however there has to be one that is bad. Check out the attached pictures....

I'll just order the roms from hobbyroms once I can pinpoint the one that is wrong. Any ideas?? Note this is a 4 board set.
 

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Your problem is not a bad eprom, there are four eproms that contain sprite info but a bad one won't cause the no sprite problem, you have something bad in the sprite circuitry between the eproms and the output to the cpu board, there are counters, adders to multiplex the background with the sprites and ECL up and down shifters from TTL to ECL that could be bad along with a few other chips that have control.
Dick
 
I have seen some issues with other boards (galaga) and it was a ram problem. I know it is not for your game but about 1/3 the way down there is an example of good/bad ram. Ram is one of the weakest point of these games (from what I have read) and can be easy to find by swapping in known good chips.


http://www.arcadeshop.com/galaga/galaga.htm
 
Your problem is not a bad eprom, there are four eproms that contain sprite info but a bad one won't cause the no sprite problem, you have something bad in the sprite circuitry between the eproms and the output to the cpu board, there are counters, adders to multiplex the background with the sprites and ECL up and down shifters from TTL to ECL that could be bad along with a few other chips that have control.
Dick

My dk was missing sprites and was an eprom issue.
 
My dk was missing sprites and was an eprom issue.

That's what I'm thinking too. Everything points to it being an eprom considering the game is playable and the game knows exactly where the barrels and mario is on the screen (because you die right where you should even though you can't see it) Plus all the other items on the screen are there (the fixed graphics) but the moving items (Donkey Kong, Mario, barrels and the princess) are gone.
 
Just an update....Mike from Mike's Arcade just emailed me as well and he thinks the problem is in the board itself too. Well if that's the case I may be in the market for a 4 board DK set that has a Z80 chip that can be taken off so I can install the HS kit. :(
 
Just for reference, I emailed Steph at hobbyroms and pointed him to this thread.


To sum up his response:
IF the roms are bad, they would be located in locations 5H and 5K (on a 4 board set). 5A, 5B, 5C or 5E are game roms (the brains) and if they didn't work the game would crash. He shares others concerns that it may be something other than the roms considering the characters are completely missing and not blotchy.



Just thought I would post this here in the event anyone else has the same problem or can point to this as a point of reference.

I've only dealt with hobbyroms a few times, but I have always been happy with their service and products and will gladly go to them again when I need assistance again.
 
The same problem happened to me today when I turned on my Donkey Kong 3. The background is there, music and sounds are there, but Donkey Kong, your character, and all the moving sprites are invisible.
 
Your problem is not a bad eprom, there are four eproms that contain sprite info but a bad one won't cause the no sprite problem, you have something bad in the sprite circuitry between the eproms and the output to the cpu board, there are counters, adders to multiplex the background with the sprites and ECL up and down shifters from TTL to ECL that could be bad along with a few other chips that have control.
Dick

Exactly. Anything in the datapath from the sprite ROMs to the final mux could be culprit. Could also be the ROM enable circuitry.

Not saying it's not the ROMs, but in most of the repairs I've done it's been in the ROM datapath.
 
(and once again someone quotes an old post in favor of the reply I bumped the old thread with)

so re-seating the eproms didn't work. not sure what to try at this point
 
(and once again someone quotes an old post in favor of the reply I bumped the old thread with)

so re-seating the eproms didn't work. not sure what to try at this point

You'd have to get the schematics out, trace out the datapath from the ROMs and start poking around at the logic that controls that path with a logic probe. I'd also check the chip selects to the sprite ROMs as well. Aside from that....
you'd have to send it out for repair.
 
FYI, if you have a soldered (non-removable) z80 you should check to see if your board has the ladder cheat. If you boot up and it says "1981 Nintendo" (as opposed to "1981 Nintendo of America Inc.") then you have the original program and a much rarer board. If you have a ladder cheat board I would send it to Dick for repair.
 
I'm kind of new to repairing pcbs myself. The one thing I have learned is that if dickmillikan gives you advise or a diagnosis on pcb issues TAKE THE ADVICE! He has seen these boards and problems before.
 
I just fixed one similar to yours and it turned out to be 5B on the CPU board had corrupt data.
 
Did you try a new D8257C chip as well. THis chip also deals with direct DMA access.
 
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