SNK vs. CAPCOM crashing after boot

[OldFoo]

Hello!



Me and a few friends recently purchased a NAOMI 1 cab at auction with SNK vs. CAPCOM game. We're new to arcade cabinets in general, but we've done some research to get us somewhat knowledgeable. My roommate is an electrical engineer so we are prepared to do anything to get it working.



When we first got the unit we moved it in to our living room, and there was a few problems we identified:



1) two of Player One's buttons didn't work

2) The screen was cut off at the top & bottom edges, as in, the countdown timer for each round of SNK vs. CAPCOM was not visible on-screen, and the power bars for each character at the bottom were also slightly cut-off.

3) Sometimes the game would load the NAOMI splash screen, get to the international warning (red text on black screen) and then fail to load.



My roommate fixed problem 1 by resoldering the ground wires connecting to the buttons, we're still not sure what's causing problem 2. After my roommate fixed the buttons, the game seemed to work fine, but then when they moved it back into the corner of the room and turned it on again, the game would not get past the warning screen. Since then, we've managed to boot it properly only once, so it seems the boot problem has gotten significantly worse.



After searching through the forum we've attempted a couple fixes:



1) Ran ALL diagnostics accessible from the service menu, and they all pass fine.

2) Checked the voltage going into the NAOMI board and we have measured them at 3.28 V, 5.20 V, and did not read the 12. The power supply is a Mighty Power Electronic Co. MP-7150A. Unfortunately, we can't seem to find any documentation on it online. We've only found a screw to adjust the 5V output as well, and no 3V adjustment screw has been found.

4) Flipping DIP switches on the back of the NAOMI to change the monitor frequency.

5) We opened up the NAOMI board, which was kinda dusty itself, so we cleaned it out, and all the capacitors, BIOS chip, CMOS battery, and traces look fine on visible inspection.



Any advice would be appreciated on how to solve the intermittent boot problem we've been having, and I've read posts with similar issues but no solution.



EDIT: One more thing I forgot to mention, not sure if it's important, but when the game fails to boot, every so often there's this crackling or snapping sound that we hear and visibly on the monitor a point of light flashes.

[OldFoo]

EDIT: One more thing I forgot to mention, not sure if it's important, but when the game fails to boot, every so often there's this crackling or snapping sound that we hear and visibly on the monitor a point of light flashes.

This happened to me and it is a monitor problem, I had to change my flyback. The more you turn it on the more damage you do. To much damage and you will kill the monitor!!! Take the back panel off and see if there is arching or sparks coming off of the flyback. Dose the screen go black when you hear the snap or crackle sound? It really sound like arching on the monitor some where.http://www.racketboy.com/forum/download ... hp?id=6922[/url]

[OldFoo]

Could he flyback be causing my other problems as well?



Also do you know of any place that I can order a new flyback for cheap?

[OldFoo]

Turn down your 5v line. So games don't like there 5v to high or low.



5.2 is way to high turn it down to 5.0 or at most 5.1



I got my flyback from Bob Roberts.



So have you took off the back panel and figured out if you have any arching going on? It really sounds like a bad flyback.

[OldFoo]

2) The screen was cut off at the top & bottom edges, as in, the countdown timer for each round of SNK vs. CAPCOM was not visible on-screen, and the power bars for each character at the bottom were also slightly cut-off.

You should have a monitor control board some where. On my Neo Geo it is on the back of the monitor, on my Big Blue it is under the control panel.



There should be a pot for V screen size and position and H position.



You may have to adjust your Horizontal width coil to shrink the sides.



The screen flash and crackle or snap sound seem like the flyback to me.



It could be arching from the flyback to the metal frame.