Controlling Power Functons LEDs

[Atr]

I'm trying to control those LEDs and I have found out that PF LEDs are always on (but barely light, approximately 10% power) if NXT is on. I can light them up fully (100% power) using for example SensorPort.S1.setPowerType(1) method, but I can't turn them off fully, only to those 10%.

Is there a way to disable current on a sensor port or something?

[s.frings]

So your LED's are obviously connected to Pin1 of the sensor port. There is a 10k Ohm Pull-up resistor inside the NXT which prevents you from switching the LED's really off.

You can fix the problem by putting a resistor in parallel to the Led's. I assume, that 6,8k Ohm would work fine.

Or you can use a motor port instead.

[Atr]

Thanks for the info about resistor. I want to use pure Lego in my creations so I'll have to live with those barely lighting LEDs