Note: Major thanks to René van den Enden, who provided everything on this page!
If you want to use composite video to play your G7400, or you want to use RGB but you own the G7400 model without an RGB port, you'll need to physically modify the console. Specific instructions can be found below, but you may want to download the G7400 PCB schematics first. This is a 1 Mb download.
RGB Modification - Recommended, if you have an appropriate RGB monitor with analog (non-TTL) inputs.
Composite Video Modification - If you don't have an RGB monitor, perform this mod. Your TV or monitor will still need to display PAL.