I've been experimenting with biverting gameboys recently and I ran into a rather odd problem. For some reason one of the gameboys I'm working on seems to only display black and white but no grey colors. I checked thoroughly for a crossed wire, but I can't find any. And obviously the contrast wheel does not fix this problem. Does anyone have any ideas? It seems this is one of the most prevalent issue with biverting a gameboy as I've found quite a few posts about it, but no solution.
I'm using the second (switchable) version from this guide: http://blog.gg8.se/wordpress/2009/11/23 d-palette/
The switch works fine, but there are no grey pixels in either mode.
Any help is much appreciated.