CarnEvil Gun Problem

Betelgeuse

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Having a weird problem with a CarnEvil I just picked up. It was working great for the first half hour, then in the middle of gameplay the screen turned to a red tint and the guns stopped responding. Even after several restarts and reseating every connector I can find in the cabinet, I still have the same problem. The picture looks like it has no Green/Blue (all tinted red) right from bootup, and in the gun test the player one gun isn't recognized. It seems almost like the gun flash is constantly being displayed. Any ideas??
 
...I've also tried booting up the game with the guns disconnected and it's still the same. I've messed with the color settings on the monitor and I can make the blue and green come through, but everything that's supposed to be white is still tinted red. Does anyone at least know what the LEDs on the gunboard represent? I can't find any info in the manual.
 
If other boards look good in the cab then you need to start troubleshooting with the video output circuitry. The guns won't work worth crap and can't be reliably tested until you fix that.
 
Not too worried about the gun if I can just get this damn monitor working. If I disconnect the red output at the jamma harness, I get just a very faint drab picture. It seems like the blues and greens aren't coming through strong. How do I go about testing the output from the pcb? I tried measuring voltage, but it seemed like the red output was less than one volt and the blue was about 1.3v.
 
Can you post close up pics of the boardset - especially the area around the JAMMA connector?
 
they should be around 0.6-0.7V if I'm not mistaken

I had a tech one time tell me he worked on a game where the whole screen was blue, it was pushing some absurd amount of voltage, I think like 3 volts at the blue header pin. he told me somewhere along the way there was a poor ground. not entirely sure what this has to do with your problem, but was hoping maybe I could get an explanation for it. :) unless your board has that problem..

in all likelihood, what else could cause this aside from damage on the board itself?

I think channelmanic wants you to track the problem back into the board itself, so follow from the JAMMA wiring for the video signal back to the components. see if there's anything noticeably suspect.
 
Well, this board seems a little out of my league. It's all machine made and I can't even follow the traces. Even if I isolated a failed component, I can't imagine I'd have the ability to replace it. It looks super clean, I don't see any scorching or cracked solder. I'll see if I can post some pics tomorrow... I'm starting to think this may be my worst arcade pickup ever.
 
Well, here's a pic of the pcb near the harness. I was able to swap the red and green leads on the jamma harness, and the picture came out green instead of red. It seems like there's only a very faint output from the green and blue pins.
 

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Checked the voltages again, I am definitely getting .6v on the red output and 1.3v on both the green and blue. Apparently the .6v is closer to correct. Why would the b/g voltages be more than double and would that cause them to not be picked up by the monitor?

Does anyone know where I can get schematics for the seattle board?
 
For what it's worth, I have had NBA Jam running in the CarnEvil cabinet without issue for the last 2 hours. I put the CarnEvil board and hard drive into a Dynamo JAMMA cab and it still came up with red only. Does anyone have an extra Seattle board? Maybe an old copy of Blitz?
 
I wanted to let you guys know that I was able to find an NFL Blitz pcb and convert it to CarnEvil in no time. The game is working great! Thanks for all the help narrowing this problem down! I'm sure glad I didn't need a new monitor.
 
The other board should be repairable... I just have to dig out one from my scrap pile to see what the video output circuits look like.
 
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