At the moment I have an X Multiply PCB that shows a “RAM NG 10” error on startup.
Although I have yet to find the problem with this board I thought it best to find out exactly what RAMs these errors are referring to.
To make any sense of this you will need the memory map for the game found in M72.C file of the MAME source code.
Here is a short list of what I have found so far:
0x9c000-0x9ffff = RAM NG 1 (Work RAM)
0xc0000-0xc03ff = RAM NG 10 (Sprite RAM)
0xc8000-0xc8bff = RAM NG 9 (Palette RAM 1)
0xcc000-0xccbff = RAM NG 8 (Palette RAM 2)
0xd0000-0xd3fff = RAM NG (Video RAM 1)
0xd8000-0xdbfff = RAM NG (Video RAM 2)