Galaga: bad CPU board causing RAM 2L error

debaser138

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I've got a Midway Galaga PCB that is booting up to a RAM 2L error. Above that, it has what looks like a backwards C and then a G so it looks like this on the screen:

)G
RAM 2L

I know the problem is on the CPU board as the video board works just fine on my other working Galaga boardset. I cleaned all the black legs on the custom chips. I swapped out the ribbon cable with no change. I also found a bad ROM (A) at 3N on the CPU board and replaced that but no change.

Seems like something on the CPU board that addresses the RAM check is having issues.

Any ideas what I should be looking at?
 
Did you ever get your Galaga fixed? I've got a board that's doing the exact thing and displaying the image upside down.

 
Reseat the video ram and the customs on the video board and make sure the cpu board is getting 5v. You can increase the cpu board in increments of .5v up to 5.2v.
 
Yeah old post with no resolution. Doesn't hurt to get the conclusion vs starting a new thread.

Thanks for the info, I hadn't looked at anything yet.
 
reviving the thread again. I have a galaga pcb doing the exact same thing.....................
 
I have this issue too as well as others. I made a thread about it.
 
Fixed mine. Turns out it was a bad connection on one of the four custom chips on the cpu board closest to the ribbon connector.
 
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