Wrong colors in Millipede

gwarble

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Hey all,
A guest pointed out my millipede colors were wonky at a party a while back (harry maybe?) and I had never noticed before, they were always like that since i picked it up and put the multipede kit in it...

any ideas what would cause this?

i tried swapping 5P and 5R on the multipede daughter board just in case which only made it worse... I also tried swapping in 5P and 5R from another multipede and got the same result

first pic is my board, second pic is from mame...
 

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i pulled the multipede kit completely and get the same colors

and in case its related, when the multipede kit was in, and switched to centipede, i got something similar to:
http://forums.arcade-museum.com/showthread.php?t=346465
i could see the bullet but are very faint when red, and eye colors missing (at least on the first level) and wrong colors as well

for what its worth
 
I would Imagine the color addressing circuitry probably has a bit stuck. Easy way to check is to look in the mame color patterns and see if that ever the shooter color shows are and white are one bit difference
 
thanks for the tip, though I'm not sure i really understand (nor know how to figure out the correlation with the actual chips involved in the color addressing circuit)

my guess about what you mean, is the shooter is supposed to be white (03, 0A, or 0B) but is actually a light purple color (07 or 0F)... neither of which are one bit off, according to the attached palette from mame


sounds like i now have two pcbs to send to you :) (finally dug out the original chips to replace the multipede kit on my dead board i asked you about a few weeks ago, unfortunately the stupid kit's pins stretched out the sockets on 5R and 5P, i should have stacked a socket in there i guess)
 

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oh got it, duh, thanks, and both the third bit (bit 2? i assume they are numbered starting with bit 0 from the right)

now i'll start looking into the schematics and see if i can figure out what parts of the circuit would be involved, and look for address lines stuck hi that could correspond to that third bit...

any idea what kind of addressing chip i'd be looking for?
 
Page 6a on the millipede schematics give you the circuits you want to look at.
 
Well many things could be the culprit I'd probably start at the 82s25 Rams lines marked ACRx and work backwards.
 
looks to me like the red and blue wires into the monitor chassis are switched
or it could be the blue and green are switched
whichever
 
Page 6a on the millipede schematics give you the circuits you want to look at.
Well many things could be the culprit I'd probably start at the 82s25 Rams lines marked ACRx and work backwards.

Bumping an old thread since I purchased this cab and PCB from from gwarble last week and am intent on fixing it. No skills with troubleshooting whatsoever and only a DMM at my disposal for test equipment. But based upon the info in this thread and the more recent work that you did on a Millipede fix here, seems the problems can be addressed by replacing the 93422 RAM at 8B.

While your issue was lines going through some sprites, I noticed as you were grounding pins on 9B, the color of the archer changed. This is the issue I am solving for. I also noticed after you removed the ground, the archer color remained altered (stuck RAM?). Replacing the 93422 RAM at 8B seems about right and I can report back once done.

Did you ever figure out what is going on with this circuit? You expressed some uncertainty in your video but didn't explain it all too well.
 
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