Naomi 1/CvS1 Intermittent boot

KYPinGuy

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I just picked up a Naomi 1/Capcom IO/CvS1 in a Capcom CPS1 conversion cab. The system will always shows a Naomi splash screen and make it to the game's import warning screen, but will only intermittently boot the game. Normally, I'll get either a black screen or it will reboot, occasionally it will die after the initial game logo screen or after character select. When it does make it to the actual game, it's solid until I turn the game off. I've pulled the boards apart and cleaned them out, including gingerly cleaning the game board's pins with a toothbrush and alcohol. Nothing looks burned, no headers cracked, no caps swelled or funky looking. The boards weren't really that dirty in the first place. Voltage at the Naomi CPU connector is 3.28, 5.1 and 12.37, respectively and multiple RAM and ROM tests have been positive in test mode. I cleared the EEPROMs at the NAOMI and game levels and swapped to a second known good PSU just in case, but nothing changed. All connectors have been reset through the troubleshooting process. Based on what I've read, I'm thinking there could be a through-hole issue at the game boards pins.

I'm a newbie in the Naomi world, but I've got lots of experience in board repair on pins.

Does anyone have any thoughts?

BTW - this is a great forum! Sites like this have taught me so much and help keep the hobby alive - keep up the great work!
 
what do you get when running self test checks on the cartridge ROMs?

It's a common problem on Naomi carts that either the pins are dirty or the buffer chips are blown because someone ran them at 5.2v or higher.
 
Yes, the game ROM tests were successful the several times that I ran it. I setup my meter for +3.3, +5.1 and +12 at the CPU and allowed it to go all of the way through the boot and load attempt before moving to the next voltage test. Each time the voltage stayed extremely stable and didn't dip at the game load or the failure point.

Would blown buffer chips allow it to boot intermittently? I thought that Naomi games pre-loaded the entire game into RAM, and therefore a blown buffer would have caused it to fail at the initial load point rather than in the game. I guess an intermittent buffer could cause corrupt data as it's being transferred to the ram and that maybe Naomi doesn't CRC the ROM load process?
 
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