Original text - Engels - How to Connect a Sega Game Gear to a TV via RGB SCART

e) Use a file/cutters to cut a chunk out of the case above the screen for the 9 pin sub-D connector to be mounted. I recommend the female version because if you use a male connector one day some dope will plug a joystick into it and break something. When filing/drilling the case, place some tape around the edges of the screen opening to prevent plastic filings from getting trapped behind the plastic. Assign one of the pins on the sub-D as the 'ground' pin and solder a wire between it and the outer metal shell (or just wrap it around the screw).

f) Next, make a DE9 -> SCART cable. If you have an RGB monitor you might want to substitute whatever it uses in place of the SCART. I built mine by cutting the end off a three meter long RS-232 (male on one end, female on the other) serial cable and attaching a male SCART connector. I find this works well but I do get a small bit of 60Hz hum in the audio from the video signal getting into the audio through signal cross talk. The only way to eliminate this would be to run the audio through a separate, shielded cable. A SCART pinout can be found here, decide on your own pinout for the D9 connector and write it down! Connecting the CVBS status line (SCART pin 8) is optional but may be required for some TVs to enter A/V mode.

g) Blow out all the dust, put the guts back in and solder wires to the 9 pin D connector and to the various places on the main board. When everything is soldered in place (and all wires double checked) plug everything in, power it up, and see what happens. Hopefully the game (you put a game in, right?) is playing on the TV. The game gear has a lot of noise on its power supply rails. In my game gear this noise got into the video amplifiers and appeared as interference in the picture. To remove this I recommend putting an inductor in series with the +5v line that feeds our little board. This inductor should have 10�H or greater inductance and no more than an ohm or so of resistance. I used a 22�H RF choke.

h) When everything is tested and found to be working, place a strip of electrical tape along the PC under the cartridge slot. Then place our modification board on top and hold it in place with hot glue along the sides. If something goes wrong later the board can be easily removed by cutting the hot glue.