Heiwa Pachinko 90s Era A23 Message Need Help Please!

[alexilla]

Hello everyone.
I just recently bought this machine from a local Goodwill. Realized how silly I was after leaving to check to see if it worked first... I am getting this message upon startup... "A23" see pic. I have tried holding the reset button down while powering up to reset however this has not worked. The machine does shoot and it also pays out of balls are dropped into certain slots on the playfield. I can't get it to do anything else. No noises, no lights other than what you see and no change in display. I have checked the fuses and both fuses are good.
Any help or direction to diagnosis would be greatly appreciated.
Thank you very much.
Alex