Apr 032017
 

Received this original Ninja Emaki PCB (manufactured by Nichibutsu) for repair:

Board gave a solid black screen.After a quick visual inspection, I noticed one IC was missing from its socket @1B on CPU board:

My searches confirmed the missing IC was actually a PAL but sadly I had no access to other same PCB in order to read or reverse the device.Here bootlegs come handy since often they are perfect reproduction of the original hardware and, judging from pictures I found online, this was my case :

I quicky managed to find a Ninja Emaki bootleg and one received it I realized that the missing IC was a PAL16R4 so a secured registered PLD hence not readable or reproducible :

My only choice was  to take this chip from the bootleg and install it on the original board.I made it and board sprang to life:

 

Game was playable but background were scrambled as you can see from above picture.I noticed that if I pressed or flexed the board in some points, the graphics came back in place.A closer inspection revealed some dry joints on solderside of an EPROM:

Reflowing them fixed the board completely.

 Posted by at 7:30 pm

  3 Responses to “Ninja Emaki repair log”

  1. Good job, it’s a real shame there’s no way to replicate registered PALs. :/

    • Well, not actually.It’s possible (altough not always) to manually reverse registered PLDs as well but most of times this involves a huge job in studying and analyzing the device.I know some people who are able to do it 🙂

      • Interesting, well no easy way I should say. 🙂 I’ve got a wonderboy 3 bootleg that just needs a PAL but it’s probably not worth the effort since it’s a boot and I don’t have access to a working PAL either.