My Cygolite Metro 420 hit the road the other day when it fell off my bike during my commute.
Next time I tried turning it on, nothing lit up. Hopeful that it was merely charged all the way down, I plugged it into its USB charger.

It immediately turned on and the charging button started flashing. I turned the light off, and the charging button kept flashing (indicating that its taking a charge). in the morning, the charging button was a solid green light (indicating a full charge). The light turned on to full power when it was still plugged into the charger, but when I disconnected, the light won't turn on, and the power button won't light up. Completely dead.

Is this something I can fix myself. If not, is it worth sending it in to have it repaired?

Given the price of a new one, I would probably order a replacement, then take the broken one apart and see if it can be fixed as a backup.

There is an Electronics forum here and they might be able to give you more help. Otherwise, as demoncyclist recommended, replace it and then do an autopsy on the broken one after you have a working one.

Thanks guys. I think I will attempt the DIY fix before getting a new one. I'm cheap like that.

Thanks for the tip on the Electronics forum. Wasn't aware of that one, haven't been active on here for quite a while.

You can get a lot of light for a little money on ebay or from deal extreme.

https://www.ebay.com/itm/SSC-P7-3-Mod...item1c1a2c456c

I would call Cygolite to see if they would cover it under warranty. So don't try to disassemble it yet.

Tel: (714) 437-7752
Email: bikes@cygolite.com

Thanks Garfield,
I was going to give them a call, but discouraged since I don't have my original receipt. I can probably get a copy from the bank since I bought it on my debit card, but it won't be original.

I know this is a several year old post, but am posting my experience here for others searching for the same issue.

I had the exact same thing happen to me. Given that Cygolite's warranty states that damage isn't covered (as is the case for virtually all warranties), I decided the three screws were easy enough to take apart and get inside. Lo and behold one of the battery connector wires had become dislodged from the plug that connects it to the circuit board. That explains everything. I plug it first into the center hole (it's a three pin plug, but only uses two) and nothing. I plug it into the other hole, and the light immediately shines. The only oddity now is that the green power light is constantly on. My suspicion is that this is something to do with the battery getting disconnected, as it seems to operate properly when charging and will briefly power off when I power off the light, but then it comes back on. I'm going to discharge it then recharge it and see if that resets the chip in some fashion, as the green light exhibiting this behavior would be useful in the factory for testing, so my assumption is that it is intentional.

As long as this thread has been resurrected: I know it's fun to poke around in nonworking electronics and there is a natural reluctance to throw something away that might be repaired. However, bike LED lights have gotten so much cheaper while getting so much brighter over the past few years that a new replacement is both cheap and provides more visibility. Perhaps the old one can be retired to back-up duty even if it can be repaired.

I don't dispute this. Cygolite's design is little changed for the metro series, so mine is a brand spanking new 1100 that I got for Christmas a month ago that I repaired, not a 450 like the OP.

Thanks for the new replies! I ended up just purchasing a new light. Which is now only my backup because I switched to a dynamo hub with BM lights. I'm never going back to batteries (for my commuter) if I can avoid it.

the 1100 truly turns the night into the dark

I find it truly amazing how bike headlights have improved over the years. The first one I had used a PR2 flashlight bulb and 2 AA batteries. By current standards I don't think it made 10 lumens. Then I had a Night Rider halogen light using a 10 watt MR-11 bulb and Ni-Cd rechargeable batteries which was brighter but fragile with limited battery life.

Then came the super bright metal arc ("stadium light") bulbs that were very expensive, required elaborate electronic circuitry, and were fragile. I never splurged on one of these and they weren't on the market for long before the LED revolution and the brightness wars that followed.

I remember when 100 lumens was grounds for rejoicing and now 1000+ is ho-hum along with very good burn times. These headlight along, with the new very bright USB rechargable tail light/flashers, have transformed night and dark day riding.

I'll post just to put in a plug for Cygolite. I've used their Expilion 750 headlight and Hotshot SL taillight for four years, with countless rechargings, never a problem, ever. Highly recommend the brand.

Bring it by and I might give you a better answer than guessing without seeing it.




....

I have the Cygolite Metro 400. It has served me very well, and I would recommend the brand to anyone looking for a quality product. Mine sees daily commuting, even in the rain. However, it recently stopped working. When I plugged it in to charge, it would go solid green light (not the normal blinky light for charge in progress). If I unplugged it, light would not turn on. If I left it plugged in and turned on light, the light would come on momentarily, then a few quick flashes, then go off.
I opened up and checked the battery, which was basically dead (less than 1V across battery terminals). I replaced the battery with an equivalent one I got off ebay and now its good to go again! There is a small circuit board + wire harness which I moved from old battery to new (it is under the outermost shrink wrap of old battery). These are Li-Ion type, and can be very dangerous if you do something wrong with them, so be extra careful if you do this.

I currently own 3 Cygolite lights and have been a customer for about 10 years or so. I have always found their customer service to be fast as lightning and extremely responsive. If you ever need anything or just have a question, just email them. They usually get back to me the very same day.