Princeton Tec Yukon

I just picked up a PT Yukon last weekend at an REI used gear sale. I knew when I bought it that there must have been something wrong with it, but for $10 I figured I'd take a chance and try and fix it.

When I first got it, only 1 of the 3 LED's worked, and it seemed to flicker a little. I thought there must be a bad connection somewhere, so I was able to open the case and probe around. Somewhere along the way the third LED stopped working. After playing around with it, it seem that all 3 LED's are dead, the incandescent bulb is the only light still working. The switch, the circuit board, all the connections tested fine. After desoldering the LED's and testing them, it confirms my suspicion that the LED's themselves have burned out. There's no circuit driving them, it's just a direct drive off 3 AA's with a resistor in series with each LED.

I found it ironic that I thought the LED's would be the most reliable part of the light, but in fact that ALL 3 of them failed at some point, all the while the bulbs shines brightly. I believe it's still the original bulb too. I just thought I'd mention this fact before people start putting too much faith in any one type of technology, because no matter how reliable you think it is, there's always a chance for failure.

Perhaps the previous user used Lithium batteries that provided too many amps to the LED's? If you have an extra LED, u can measure how much current is being provided by regular alkalines. If withing spec, this may be a good opportunity to upgrade to one of these LED's http://candlepowerforums.com/vb/showthread.php?t=89759. It's a very informative thread - many LEDs are slowly killed when overdriven.

I had the same problem with my Yukon.One of the LEDs started to flicker then burned out 2 hours into it's first use.I was using alkaline batteries not lithiums and my Yukon is brand new.

I did end up replacing the LED's with the 35K mcd white leds. I also replaced all the resistors in there with 10 ohm, 1/4 watt resistors. I think the cause of the probme is from PT using too low of a resistor value. The stock resistors were 3 ohm, which is overdriving the LED way too much. With the 10 ohm resistors and somewhat dead alkalines, the leds are running a little more than 20 mA, still very bright. With fresh batteries I am guessing this number would be in the 30-40 mA range.

I didn't like this headlamp as much as I hoped I would. It's a lot bulkier and heavier than all my other ones, plus the cord running to the battery pack always seems to tangle up in the headband when it's in my backpack. I'll probalby just keep it in the car for emergencies.