Burger Time graphics issues

yaryar

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Currently stumped on this Burger Time I'm working on. Graphics are as-seen in the pics. Did some reading on the forums but nothing specific to what I'm seeing. The only thing I read was from a post mentioning grounding the outputs of the LS194s after the graphics ROMs. Doing that doesn't move the misplaced parts of the graphics that are being seen on the screen. Swapping the bottom board(the one with the CPU-7) fixes the issue, so it's related to this board in the stack. Also swapped the 6 graphics EPROMs as well. Looking at the screen, it appears the misplaced parts are OK on the vertical, but not on the horizontal. Used the SLICE comparator on most of the chips on this board and all nothing flagged as faulty. What am I missing here???

As always, thanks in advance for any advice!!
 

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Thanks Mark. You pointed me in the right direction. Addressing to those RAMs looked good, so I next piggybacked those RAMs one at a time, noticing graphics changes when piggybacking 4J and 5J. Replacing those fixed the graphics issues.

Final issue will be fixing a no coin-up issue. Hitting the coin 1 switch, I can see pin 4(generates /NMI to the CPU 7) of the LS02 at 7A toggling. If I ground that pin, the gameplay freezes, so I know I have good continuity to the /NMI on the CPU. Assuming the pulse width to that LS02 is probably not correct, causing the no coin-up issue. Thinking the next step will be to trigger the coin 2 input to see if I get the same result with that input.
 
Once one of those flops flips it stays fliped until the NMI routine clears the NMI by writing to $4000.
The 555s are just there to debounce the coin inputs and clean up the pulses.
 
Understood about the debounce/cleaning up the coin pulse. So if the CPU7 is seeing the /NMI pulse for coin switch, what could be preventing it from going into the "press start button" routine and out of the attract mode? I know the issue is on the top PCB, as swapping with a known good top PCB allows the game to function properly.
 
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