Gokujou parodius, vertical bars repair log.

[Artemio]

I got this game in a lot of non working boards. It was the first one I jumped to since I didn't have any other GX Systems. The game had vertical bars:



Using the test menu I found out the issue was ROM 28G. Since I had fixed two boards with similar issues the same day, I proceeded to desolder it and change it, without verifying the lines first.

That didn't fix the problem.

I must note that the PCB is in very good shape, no traces appeared damaged. I had to isolate if it was the top or bottom row, since form the rom all data and address lines worked perfectly.

In order to figure out where the data bus was going through, I used a blank 27c160 eprom. Then i searched for the line s that had only 1s in them and noticed that one of the 8 data lines wasn't reaching the connector that goes to the main board. It was pin 16 form the Mask ROM, and it went directly under the Mask ROM just next to it.

I desoldered it, and found a nice surprise under it:



Cleaning and using a jumper to patch the trace fixed the issue.

[channelmaniac]

Nice fix!