20 Sep 2017

Bad Dudes VS Dragon Ninja - Data East 1988 (repair log)

Game booted but with jailbars and corrupted graphics:

This game runs on Data East MEC-M1 hardware composed of a CPU board and a ROM board. I dumped the ROMs and for n°20 (EI20 on the sticker) my programmer reported "some pool pins":

I burnt a new one and graphics were restored. However sprites were absent:

The sprite area on the CPU board is at the opposite side of the JAMMA connector. I started to probe ICs and found one LS74 @ 18B had one weird output. This was confirmed by the scope, the low level for this signal, supposed to be close to 0V was more like 2V. I installed a socket and put a new chip in it and sprites reappeared:

Game fixed.


  1. backgroud graphics is not correct

    1. They are, only problem is my monitor having saturation issue (called by my friend "Fanta" effect as everything looks orangy).