RCA Pro Sound is a modification for your Game Boy DMG to allow louder, clearer sound.
Game Boy DMG
28 Gauge wire
2 RCA panel mount jacks
2. Separate the two halves by gently pulling down on the ribbon cable joining them.
3. On the back PCB locate the ground, right and left, audio terminals as shown in the pictures.
4. Cut 3-4 wires 6 inches in length.
5. Solder 1 wire to each of the 3 terminals (the pictures show 5 wires for a dual 3.5mm and RCA pro sound, you only need 3).
6. The bottom terminal is the ground terminal, the one above in the middle is the right and the one on top, the left.
7. Prepare your front shell by removing the front PCB and buttons.
8. Drill two holes directly between the top two screw holes with good spacing between the two. Don't make the holes too close or you wont be able to plug in your cords.
9. Drill the holes slowly and with a stepper bit and use the manufactures recommended hole size. If you do not know the holes size, slowly drill a larger and larger hold until the port just fit.
10. Prepare your R and L RCA jacks by removing the nuts on the top.
11. Insert each of the RCA jacks into the holes and secure with the recently removed nuts. The ground ring should be put on before the nut.
12. Solder the ground wire to both of the ground rings as shown in the picture. You may use two separate wires for each jack if you prefer.
13. Now solder the R and the L terminals as shown, making sure the R matches with the right and the L matches with the left. (always use hot glue to secure your wires)
14. Make sure your ports work before replacing the front PCB.
15. Replace the front PCB. Try to orient your jacks so that you can get your PCB as flat as possible.
16. Reinsert the ribbon cable and screw your Game Boy back together.