This sounds like it might be worth checking: https://www.jammarcade.net/out-zone-repair-log-2/Appreciate the info but I dont have the tools to fix it at the moment. Otherwise just shotgun swap the object ram as you say. Whichever it is, and hope for the best.
Yeah could be. I guess I need to find a good magnifying glass/lamp. My old man eyes are only trained to spot pink bullet sprites.This sounds like it might be worth checking: https://www.jammarcade.net/out-zone-repair-log-2/
Schematics are here: https://usermanual.wiki/Document/OutzoneSchematics.4185164285/view
Maybe someone can point you where the Object RAM is. I would start by checking the RAM and if they are OK, then going backwards to the chips that create the control signals for this RAM.