Dec 292016
 

I received a Golden Axe system 16 boardset, advertised as untested. When it arrived, it booted to a black screen. It still had a custom Sega encrypted CPU on board,  which means it likely suicided. I swapped in a stock 68000 CPU and desuicided the rom board by reprogramming decrypted program roms. The board booted up with full audio and at a glance seemed to play fine… until I started a game. Immediately I noticed the backgrounds were fine, but all of the sprites were “squished” into a one-row column of pixels. Unfortunately I did not take a photo when the PCB was in this state. I was able to observe the column of pixels changing color, which told me this was likely a complex logic problem, and not ram/ TTL logic related.

I turned to the schematic and the mame source code. I quickly learned that the 315-5196 custom Sega IC was responsible for sprite generation. In my parts PCB inventory, I have a nice condition System 16 motherboard where the corners have been snapped clear off (25+ traces damaged).  It was perfect to pull the suspected faulty IC.

Using my hot air gun, I removed both the suspected bad IC, and the donor IC.

And then I prepped the board for install (also with hot air gun). The chip went in without a problem, I heated the area until the solder was liquid, and carefully dropped the donor chip into place.

The result… total SUCCESS! Graphics are fully restored, game plays 100%. Repair complete.