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!

Seibu 'SEI0060BU' reproduction

The 'SEI0060BU' is one of the many custom ICs you can find on Seibu/TAD Corporation arcade PCBs (Toki and Cabal to name few).It comes in a 600mil 42 pin SDIP package :

It accomplishes graphical functions and it's used in tiles/sprites circuits.Recently I had the chance to get an original faulty Cabal PCB where this custom IC was replaced by a daughter-board :

This daughter-board was actually a full TTL implementation of two 'SEI0060BU' hence for my reproduction I had to figure out the circuit for a single custom IC.Schematics were done after some time and PCB layout sent to manufacter.By using TSSOP devices (the smallest package I could find) the reproduction was slightly bigger than orignal part :

I could succesfully test the replacement in my working Cabal and Toki PCBs :

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