PCB Repair: Raiden Fighters
Problem
Dead.
Diagnosis
This version of Raiden Fighters runs on the cartridge-based Seibu SPI system. Here is the motherboard with the cartridge removed:

I noticed that there was flux residue around one side of the i386DX CPU. Upon closer inspection, almost none of the pins were actually soldered to their corresponding pads. Another side of pins, though seemingly untouched, had also come loose. After carefully reflowing the two sides and checking that each pin was soldered down, the game miraculously came back to life.
Fix
Reflow pins 67-132 of the i386DX CPU.