Got for repair this Neo-Geo conversion cart of Zupapa! a platform released in 1994 only for MVS system and not on the Neo-Geo AES home console :
Most of graphics were blocky:
I opened the cart:
As I said, the cart was a conversion from a donor hardware, this requires the ROMs to be replaced with game code and data plus some other modifications like adding some ICs and jumpers.Doing a visual inspection on work done I found nothing of abnormal until I came across this:
One of the zero Ohm resistors used as jumper required by the conversion was badly soldered.I put it in place and magically all the graphics came back:
A simple but effective fix!