Nov 182015
 

I bought this faulty Point Blank PCB for cheap on Ebay:

Point_Blank_PCB

Seller said it had graphical corruption and was missing a primary color and sound.When I powered it up I actually had sound but the other two issues were there:

issues

The missing color was the green, tracing the pin 12 solderside back from JAMMA connector I found the culprit : one of the three SMD transistor ( each of which drives a color output) was missing:

missing_green_transistor_

Green was so restored :

green_fixed

but graphical troubles were still there.Inspecting the board I found that some pins of the custom C355 were smashed:

C355_closeup

This custom handles the motion objects (sprites) and my issue concerned this part of graphics.Having a spare Namco NB-1 board I opted for a replacement of this ASIC :

 

C355_reworking_

After some work and pads rebuilding, I ended up with this result:

C355_replaced

In this way graphics were completely restored but sprites had jailbairs:

sprites_jailbairs

Pressing down the board fixed the issue temporarily, inspecting again the board revealed a liften pin on a TC51832 (62256 compatible)RAM @12R:

TC51832@12R_lifted_pin

Resoldered the pin and board 100% fixed.

 Posted by at 10:30 am