QUOTE(adimifus @ Aug 29 2012, 06:39 PM)

Agghh... Its been driving me crazy as to why I couldn't swap the green controller LEDs with purple ones. Nowhere I looked before now said anything about purple LEDs not working on some controllers. I tried a different color (pink-- which looks close enough to purple for me anyway and am happy with the results) and it works fine now. I went through too many purple leds thinking they were bad or I messed them up soldering. What controllers work with the purple LEDs, anyway?
Your not alone. Just did this yesterday.
RF board I put blue power and 4 purples.
Then on controller I put a purple, nothing. And it was a wireless controller so everytime I wanted to test it I had to hold the battery pack up to it and then short the power button on.
After a while I removed it and tried P2, p3 and p4, nothing. Broke 2 when trying and lifted the lower pad on player 3. Tested with multimeter and confirmed power going through.
Then I decided to wire up the pads to test individual lights. blue worked good. put purple back, nothing.
Then quick google said purple needs more power, explains why was fine on the RF board.
so i opted for 1 Blue, 2 red, 3 red, 4 blue.
Also noted when putting AA's batts and not the rechargable, purple did light up, but incredibly dim.
When playing around on the rf board I did notice if I ground the negative, the LEDs lit up 3x or more brighter.
Im guessing the purples would be good in a wired controller, Arcade stick setup.