Primal Rage arcade (Help needed)

[Eruption2405]

Hi everyone, im new here but I'm desperate for some help.

My oldest son is going off to Uni, and we decide on a project before he went off and brought a Primal Rage arcade.

We have got alot of thing working so it now turns on properly, I.e monitor and lights but once it begins to boot we are greeted with a scrabbled screen (aatached photo 1). If we press button 3 (top left button) we get a beep and then a screen with work ram bad on it (attached photo 2).

We have been over the board and cant see and visual issues. We've looked though the operators maunal and cant find any answers to try fix the problem.
Ive had a multi meter on it and the both the 5v and 12v lines are there and stable. Ive looked on the Internet for hours and days but can find anyone with the same problem either.

Can anyone give us some tips, advice or anything to try resort this arcade to even boot up to test the roms properly. Im desperate to make some progess before he leaves in just over a months time if possible.

Thank you for your time reading the post.

 

[xga]

Sounds like you might have a fault with one of the SRAM's used for the work RAM which I think might be located at 21K and 21M/N on the main CPU board. They should be socketed, so they are nice and easy to remove. Hopefully you have the means to test them. If not, you could try swapping them with the SRAM's from locations 12H and 16H and see if the behaviour / error message changes.

It might also be worth seeing if the board is well enough to enter into the service mode so that you can conduct various RAM and ROM tests from there.

 

[Eruption2405]

Sounds like you might have a fault with one of the SRAM's used for the work RAM which I think might be located at 21K and 21M/N on the main CPU board. They should be socketed, so they are nice and easy to remove. Hopefully you have the means to test them. If not, you could try swapping them with the SRAM's from locations 12H and 16H and see if the behaviour / error message changes.

It might also be worth seeing if the board is well enough to enter into the service mode so that you can conduct various RAM and ROM tests from there.

Thank you for the reply, i do appreciate any help.
I dont have a way to test them, what would I need to test them?

We have just tried to change the chips over as you suggested and now get a new screen but no error code, no matter what we touch though the colour will change to green and then some artifacts appear at times too.

 

[Eruption2405]

We've just put the chips back to the original orientation and not get both, work ram bad then cycles to color ram bad

 

[Eruption2405]

We tried some different placements of those 4 chips and get video bad ram