Taito Legend of Kage arcade pcb repair #2
Game just booted to a solid white screen with the CPU in a watchdog reset loop. This game, like Bubble Bobble, uses custom package RGB DAC’s that are known to fail (and also need +12V and -5V connected to work) but it seemed the palette RAM was actually passing full white to the DACs so the initial problem wasn’t there.
Usual test first is to check the program ROMs – and one wouldn’t read at all due to some kind of internal short. When replaced the game ran, but without any sprites or tilemaps but at least it proved the RGB customs were working.
RAM on the video board all tested fine, but what looked like some dirt on the board actually turned out to be a massive gouge that had broken 10-12 traces. When patched back up the game was fine.