Remove the reset task house.. the voltage between pin 1 & 2 ( 26 Vdc).. remove the measuring head housing. replace the fuse (2A). Well known dead LED problem with all Corsair keyboards. Had the (very expensive) K95 for a month and 4. A little over 2 months and this keyboard has eleven dead LEDs. It had dead LEDs shortly after I received it but 1 or two was an annoyance, not.