Sega Afterburner arcade pcb repair
Game ran but sprites were garbage – bad positions and lots of corruption.
I ran the self test before doing much more – and it came back with bad custom IC30. This is actually a math coprocessor, and the main CPU uses it for maths to position all the sprites in screen space – so if it fails sprites will be corrupt.
Luckily I had a spare for this chip from a Thunderblade parts board. Game was perfect after I swapped it in.