Question: what model of 4000 you have? Desktop or Tower?
Desktop use a regular "square" LED.
Tower use three ordinary "mini" LEDs.
LEDs don't have "voltage" (their typical voltage drop is around 1.5~2V). The current (amperage), who is really matters, is 15~20mA for maximum bright.
Bigger "round" LEDs need up to 30mA (milliamperes) to achieve maximum bright. So the square LED.
