Yes, with winter fast approaching, I am forced to ride at night so I bought a Cygolite HID as the price was right. Due to my butterfingers, I dropped the light and broke the bulb. All benefits of HID evaporated as all the bicycle HID systems are not user servicable due to product liability and high voltages involved.

But I have a little more than passing experience with high voltage (and high voltage AND current, 12 KV @ 30 A :O) so I decided to see what Cygolite uses...

Its a Welch-Allyn, no surprise. They make most small HID lamps including the Cateye Stadium. And at WALAMPS.COM, one can buy a replacement bulb, only difference is Cygolite serializes the bulb and glues an o-ring on the front glass. A thin bead of Dow Corning high temp clear RTV will do the trick with the original o-ring. The Welch Allyn part number, stamped on the bulb along with WALAMPS.COM is M10P002. Price is $120 each online.

I have a request in to Cygo for a repair quote but have ordered a replacement to have on hand.

nice info Weisse Luft !!! Will come in handy if the same will happen to my lights.