I have a multimeter, but the pins on the ribbon cable connector are too small to measure, and I can't find this information. Hope someone can help me out.
Front side (ribbon cable connector)

Back side of GBA (has 20 connections, I know the screen only uses 20 pins of the ribbon cable).

I need this information because I want to hard wire a GBA TV adapter to my GBA. (The normal connection is unstable.)