LEDs: Common 0805 SMD LED
All resistors are valued between 10 and 100 ohms.
If you are using a clear case kit, use the LEDs with proper color (cool blue - ice blue, green - phosphor green, red - phosphor red, etc)
Note that LEDs with lower forward voltage drop (regular red, green, yellow-green, etc) must be paired with proper current limiting resistors!
This circuit will *usually* fit right into the stock or aftermarket slot covers without modification, but if it doesn't, you can file down the sides. You don't have to populate the LEDs.
Lower the current on the LEDs if the console freezes on start-up, or the LED gets dim fast.
Attributions and credits:
This project and files are based on the "gbcartbreakout" project. https://wiki.nonchip.de/GameBoy/GBcartBreakout