7

I just bought my first hub dynamo (Shutter Precision PL-8) with dynamo headlight (Busch + Müller Lumotec IQ2 Eyc N Plus). After installation I figured out that light is not working. How to determine what actually is not working?

  • You need some sort of a voltmeter/continuity tester. – Daniel R Hicks Mar 31 '16 at 12:08
7

When checking a Dynamo system, there are 3 basic items which need confirmation:

  1. Power Supply: Is your dynamo producing power? Checking this requires a multimeter, preferably with alligator clips on the wiring, and to spin the hub. Or there are specific tools, as well.
  2. Wiring continuity: Are all connections tight? Are there any breaks/shorts in the circuit? This can also be checked with a multimeter. It is best done by isolating each section of the circuit to check, and then verifying the connections between the sections.
  3. Light Source: Last, check your light source. Change the bulb if possible. Use an alternative 6v power supply to check whether the light head is functional or if there is an issue elsewhere in the loop.

Busch & Muller make a rather expensive tool for troubleshooting a dynamo.

catalog showing Light Diagnostic Tools and Mains power adaptor for B&M Lights

| improve this answer | |
  • 2
    Good points. Actually, I'd recommend your step 3 to be first: Disconnect cables from the dynamo, and connect a power supply instead. That immediately tells you whether light bulbs and wiring are good, which are the parts most likely to fail. While the dynamo itself can also fail, that is fairly rare in my experience. – sleske Mar 31 '16 at 13:45
  • 1
    I have made 5.2v DC power supply using four 1.3v batteries in series (i.imgur.com/R3ePfs4.jpg). Contacts sparking and heating up while light connected to it but still not working (i.imgur.com/Pab8RSi.jpg). Seems like it short circuit somewhere inside lights. – mrchnk Mar 31 '16 at 20:05
  • 1
    Yes, looks like short circuit. B&M are high quality expensive lights and I think it's unlikely that the problem is inside the light, so I would check the cables and in particular the clips where they connect to the light, perhaps one of the thin copper threads is making contact with the other wire. – Stephan Matthiesen Mar 31 '16 at 21:51
  • 1
    Cable for lights is two separated wires and no way there could be short circuit while I connect it to battery pack just in front of my eyes. I think circuit inside lights could be damaged or something. What do you think? – mrchnk Apr 1 '16 at 6:48
  • 1
    I'd say you have an issue with the light. Have you contacted the manufacturer? – zenbike Apr 2 '16 at 0:14
2

Thanks for replies everyone (especially zenbike)

After light disassemble i found out what was the actual problem. There was a extra-solder where wires soldered into board that causes short circuit. After that extra was removed light have come to life (YouTube).

extra-solder

Busch + Müller are high quality expensive lights, but seems like it is not expensive enough for simple quality-control testing

| improve this answer | |
  • I bought one of their lights and the LED was loose inside the headlamp. They're relatively expensive but I am surprised to learn that their reputation for quality is not good. – Yolo Perdiem May 16 '16 at 0:36
  • @YoloPerdiem I have to agree – I am so far very unimpressed with their build quality. – Will Vousden Oct 21 '19 at 16:15

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.