That's probably the problem. I had a similar attempt using hotd 3 wiring and never got anything out of the guns using the hotd 3 gun board to gun cables into a hotd2 gun harness.
I never got anywhere using those parts and ended up buying a hotd2 cab(my boards used in previous attempt worked fine...
https://www.mameworld.info/ubbthreads/showflat.php?Cat=&Number=314298&page=&view=&sb=5&o=&vc=1
This post is old but has some info. It's looking undumped.
Do you have the led emitters wired in the proper sequence/physically in the right order?
Doe any of the values change at all in a gun calibration screen?
Is the trigger being pulled recognized?
Is there 2 harnesses going from gun board to io?
I remember doing alley oops on the snes version back in the day with my older cousin. I've never played the arcade version at all. Is it possible there's a Mandela effect from playing home versions? I'm thinking back then games really weren't ported from arcades to consoles and were...
I own a pacman arcade1up for the wife.
I wouldn't trust the wood to hold up a 20 in crt monitor. It's cheap particle wood.
Youre going to need upgraded buttons and levers,a jamma PSU if that is your end goal..etc..etc..
You'd be better off finding cabinet plans online and diy'ing it imo.
Check the daughterboard connection in the netdimm if you still have it apart .
Does it his Naomi have these issues with a regular cartridge game or just the netdimm?
I had a stick of ram in my netdimm that was bad but would always be "ok" on the test screen. I had similar random freezes until I swapped it out. You might try some new ram sticks.