tech: konami aliens pcb

chips4sle

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hey
i have an aliens pcb
the word works but some of the graphics are messed up
in test mode it shows 4 of the 8 masked roms are bad
j2
k2
j8
k8

im sure there not bad its just a ship that controls them thats bad but i dont know what chip that is
anyone know
 
Those are all of the sprite gfx ROMs (according to the data in MAWS), so I'm kinda liking your theory that it might be a logic-chip that enables them. Unfortunately, I don't see any schematics of that PCB online, so it's going to be hard to identify it.

You might start by checking the OE and CE pins (maybe pins 22 & 24, check the pinout of the type of ROM you've got) for activity with a logic probe. Trace each of those pins, on each of the ROMs, to where they are connected. If they go to a common IC... and the logic probe confirms active inputs but inactive outputs, swap 'er out.
 
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