Dogyuun repair log

Received today from Japan a box of faulty PCBs, very good titles inside like this Dogyuun (by Toaplan)

Board was really in mint condition but it did nothing upon boot, it just sat on a black screen :

 

As always I started my troubleshooting with a visual inspection and focused the attention on the surface mounted devices.I promptly spotted some bents pins on one of the 'GP9001' custom ASIC (board carries two of them) 

At first glance tthey seemed to be shorted with the adjacent pin but even straightening them the situation did not change.But on the other 'GP9001' custom I found a detached pin :

According to pinout of the ASIC (taken from Knuckle Bash schematics) the involved pin was a data line (D6) shared with 68000 CPU data bus :

 I reflowed the pin :

This made the trick!

Board totally fixed.Simple but effective!