The defects (4 of them, it was) have just been stashed away in a box ever since my first test of them.
One of them was a bootleg Ginga Ninkyouden; a pretty frakked up beat'em'up by Jaleco.
The backgrounds, text, sounds, controls and gameplay was good, but all the sprites were messed up.
It looked like the sprite-parts displayed fine, but in the wrong place.
Easy to see here in attract mode, where we have a line-up of most of the baddies starring in the game.
Started by shortening adjacent address and data pins on the different RAMs observing the screen.
That way I found RAMs used for colour, backgrounds, and texts, but no sprites.
Well it turned out, that the sprite RAMs were on the main board after all.
After having read GameDudes repair log on G'n'G over at Aussie (http://www.aussiearcade.com.au/showthread.php/20920-Ghost-n-Goblins) that also had misplaced sprites, I started poking the 273s on the main board.
Soon I found, that the one at V7 had both pin 12 and 13 stuck at high, while all the other in- and output were very active when there was sprites on screen.
By beeping, I found, that all the remaining inputs were tied to a an in-/output on the 245 just next to it at M8.
Only one was not (the plot thickens, MUAHAHAHA!). Tried to connect the two pins by just poking a piece of wire at both, and viola: All sprites back to normal!
I consider this case closed...my first REAL arcade repair };-P
Fed blog.
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Så for man jo endnu mere lyst til at donere pcb'er til dig, når man kan følge processen = lære noget.
Google translated:
Fed blog.
Is the book market.
So one is even more inclined to donate PCBs to you when you can follow the process = learn.
:)
Thanx };-D
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