Aug 212015
 

Got this faulty Knuckle Bash PCB in a trade with my friend Ifog:

Kuckle Bash_PCB

For the uninitiated, it’s a side-scrolling beat ’em up developed and published by Toaplan in Japan in the 1993.

As expected, on the power up I was greeted by this scenario:

issue

Game was playing almost blind, all graphics were totally wrong replaced by colored blocks.All the GFX DATA are stored in four 42 PIN 16Mbit MASK ROMs:

GFX_MASK_ROMs

These devices are addressed by the near custom ASIC ‘GP9001’ @U13 which is the graphics processor unit of the system:

GFX_custom

Also schematics confirmed this:

GFX_MASK_ROMs_addressing

When I went to probe address lines of the MASK EPROMs, I found that most of them were silent.A closer inspection revealed the many pins were lifted.Pressing the custom chip with a clamp (a rude method perhaps but always effective) restored all the GFX :

fixed_with_clamp

So, I did a reflow of the custom chip passing the iron tip on its pins (with the clamp still in place) and this fix GFX stably.

Last thing to do was replacing some leaking 10mF axial electrolytic capacitors in the audio section (luckily corrosion didn’t involve any traces ) :

leaking_capacitors

Another great game preserved to eternity (well, hopefully…)!

P.S.

This board turned to be an undumped Korean revision.I sent dumps to MAME developers.

 Posted by at 7:25 pm