Got this game for a repair which had all screen with washed out colours
This game has a SEIBU custom named UEC51 which is used as a DAC to output the RGB colours on the monitor.
The input pins were good, but a couple of output pins were fixed, thus creating the images as they had less shades of colours.
I took a good one from another Toki which had other faults and the problem was fixed 100%
The game had two problems.
First one was the music that sometimes when switching on the game was glitched (very fast tempo or corrupted voices)
The first problem was fixed by replacing capacitor C7 which was used to reset the chips and didn’t work correctly.
Second problem was some black pixels on some elements of the background.
After shorting some data lines of the gfx maskroms I found the one responsibile for the background images.
Normally when a markrom fails you get blocky graphics. In this case was only some bad pixels.
Looking on the solder side of the pcb I immediately noticed one pin of one address line of the background image markrom touching the network resistance beside which forced the address line to 1.
Disconnecting it solved the problem
Received this game for a repair.
The game had messed background images
Shorting some data pins rams I found the one responsible for the tiles arrangement.
I replaced the one marked in red below and it was infact faulty but it didn’t fix completely the problem.
I noticed that the 74ls745 above it was pressed down badly like if it was hit but something.
I decided to unsolder it and test the continuity of all the pads and infact I found three of them (marked in red) that visually were OK but they had no continuity
with the other chips.
That meant that the internal pad was broken so bad it detached internally
Making some ugly flying wiring with something I had at hand I tested the game which was fully restored
The game belonging to my personal collection didn’t boot anymore after several years kept in storage.
Game was in mint condition but the address decoder custom 34 had lot of oxidation on the pins (common problem on these custom chips) so I proceeded to clean and reseat it paying particular attention to avoid breaking pins which generally are really weak.
Game booted but it developed the following problem
After probing around on the rams and TTL for suspicious signals with no luck I decided to dig up my dead Gaplus board which I kept in my garage for Namco customs spare parts and checked one by one each custom.
After changing the CUS20 (tilemap and sprie address generator) the problem was fixed
Another Fujitsu chip left our world.
Got another Konami game with the usual jail bars defect that is so common on these games
I ran again the maskrom test and it reported bad maskrom 8B.
After desoldering it and testing as 27c160, the programmer complained about missing contacts on several pins.
After replacing the markrom with a 27c160, the game was 100% fixed
