konami lifeforce - please help

Mystical pigeon

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My treasured lifeforce pcb has developed graphics glitches/garbled graphics. The game is running fine in the background.

I have spent days checking all the usual problems with no success (voltages, ram, roms, logic ic's), and have reached the point where I need a circuit diagram/schematic to carry on. I have searched loads of sites, but cant find one. The nearest i can find is a nemesis circuit diagram, which shares the same graphics board, but i really need a diagram for the top board, which is a gx587.

Please can anyone help me out with a schematic? I would hate to have to scrap my favourite board!
 
nice! I didn't even think they made schematics available for games after the mid 80s.
you see them for the early games but not so much for the post 1983-84 games!

schematics are fun!
 
Thank-you so much shadows for the excellent scan, i really appreciate it.

hopefully i can bring my sick board back to life, i will post a repair log if i manage it.
I owe you a beer my friend!
 
If you don't mind me asking, how did you determine the fault is with the top board? Reason I ask is that I'm still chasing down a problem with my lifeforce doing this (see attached pic), and have been spending most of my time on the bottom board. And for the record, VRAM (and logic chips around vram) is fine. I also get the same pattern of missing lines in the crosshatch.
fc8qc.jpg
 
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To be honest, I am still not 100 percent sure that the fault is on the top board.
It is just that everything on the bottom board seems to behaving as it should when checked with a scope against the drawing I have for it. Initially i suspected Ram, but these seem ok. All the TTL control seems ok too, but there is always a chance I have missed something. I even went to the extreme of socketing and substituting all the 4164 and 4416 drams, even though they tested ok.

Thanks to shadows supplying the correct diagram, I can at least now take a fresh approach on the top board, and work my way back from the output. Also, the drawing gives information on the top board custom chips that are envolved in graphics processing(that i am hoping are not at fault!), also the pinouts of the mask roms are useful.
 
I'm in a similar boat, also did the shotgun approach of replacing the dram chips, only to have the issue remain. I'm a novice at troubleshooting (using a probe), so will be watching your progress as you investigate the top board. Also many thanks to shadows for posting the top board schematics!
 
I have one that had messed up graphics too, you might want to replace the ribbon cables as when I fiddle with mine, the game most of the time boots.
 
I would dump the roms and run them through mame to make sure they are working. At the very least verify the program is corect. I would also check all clocks to the the ram and any other clocks for that matter since you have the scope handy. Buffers are another easy thing to check with a logic probe or scope.

I would lean towards a bad connection some place and what happens if you slightly flex the pcb a little in 3 or 4 different places>?
 
I have a board very similar to Dave's except I am missing some lines in the OBJ ram also.

It is definitely a problem on the vid board. I get the same missing lines when I do a swap
with Nemesis.

The Fujitsu LS245 seem very prone to fail on this board. I weeded through them with a probe, next board
I would just shotgun them all and save time.

8448125741_57b0159ff5.jpg
 
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Just a quick question,

I have made dumps of the program eproms and ran through mame they come back as ok.
I have not been able to dump the 1mb mask roms and verify them, because i am not sure what device type to set my programmer to in order to read them?? Do you know??
 
Thanks for the help and link, that is very useful information.

I spent some time checking the graphics board again last night, and I think I have indeed found a dodgy 74LS245 at 12C. (Cant believe I missed it before!) Im just waiting now for the replacement to arrive, hopefully that might cure it. :)
 
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