Jul 212016
 

Got this Devil World PCB as non working. This game is running on a Konami Twin 16 hardware. It is a two layer board with the first one devoted to CPU/sound and the second one to GFX/video. The two faulty/replaced chips were on the video board and are highlighted in red.

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Luckily the board was booting and got stuck on the RAM/ROM test screen with ROM #18 reported as bad (chip #1 on the board picture above).

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That ROM is part of a 4 ROMs row which contains the GFXs. They are 40 pins Konami chips and looking in MAME I could see that they were 512kb MASK ROMs. I tried dumping it with my programmer but was unable as it found one dead pin. Compatible EPROMs for these are 27C400 so I burned one and replaced it.

The game was now booting but with a color problem on some tiles.

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After a deep look at the video board I could find a Fujitsu 74LS153 located at 10H (chip #2 on the board picture above) with floating outputs (while inputs had healthy pulsing signals). I piggybacked it and got everything corrected. I desoldered the faulty one, put a socket and replaced it. Board is now working perfectly.

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