Galaxian Board Repair Help: Bad Ram 2

QuartrArcade

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Starting to get more into fixing boards these days. I'm slowly learning the basics, but I'm stumped on this one. Original Galaxian board, reports Bad Ram 2 error. Already replaced the two 2114 chips that correspond to this error with no change. Also replaced the 2101 ram chips as I was able to test them with a 9010a and they tested bad.

Now I'm stumped, I've started poking around the board and found that two address lines off the Z-80 are dead, A7 and A10 (pins 37 and 40), but don't know if this is relevant or not. All the other address lines appear to be active and normal compared to a working boardset.

Any advice here?

Thanks,
Anthony
 
Starting to get more into fixing boards these days. I'm slowly learning the basics, but I'm stumped on this one. Original Galaxian board, reports Bad Ram 2 error. Already replaced the two 2114 chips that correspond to this error with no change. Also replaced the 2101 ram chips as I was able to test them with a 9010a and they tested bad.

Now I'm stumped, I've started poking around the board and found that two address lines off the Z-80 are dead, A7 and A10 (pins 37 and 40), but don't know if this is relevant or not. All the other address lines appear to be active and normal compared to a working boardset.

Any advice here?

Thanks,
Anthony

Does sound like you have a bad buffer between the RAMs and the CPU. Also check the pins on the 2114 RAM for activity.
 
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