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Diagnose my Dynamo Light Issues...

(61 posts)
  • Started 10 years ago by Wilmington's Cow
  • Latest reply from wingpig
  • This topic is not resolved

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  1. Wilmington's Cow
    Member

    Grrr!

    My first B+M Lumotec light had a hell of a rattle, which turned out to be something to do with the standlight which stopped working (I still need to prise it apart to see if I can fix it). That got replaced, no bother (and I got to keep the knackered one).

    But the replacement has now developed a 'flicker'. Basically intermittently it stops working. Fortunately the tmies it IS working are enough to charge the standlight, so I have some light, and I've a little back-up on the bars, but it's getting irritating.

    I checked the wires last night, and while everything was in order I still cleaned things up a bit, and still this morning there was the flicker. It could be the light, or possibly the hub. Hard to tell if the rear light is going off too as, 1. I can't look at that while riding, and 2. its standlight is much better, it doesn't dim when the wheel stops moving, so after getting a bit of charge any dimming on the front wouldn't be replicated on the back.

    Not at all what I expected from my first dynamo-lit winter! (I think I've just got unlucky, but I might swap over to the knackered light as the backup bar light means I don't miss the standlight too much, and if the flicker is still there I know it's probably the hub.

    I think I've answered my own question on how to work out what's going on...

    Thanks.

    Posted 10 years ago #

  2. Uberuce
    Member

    Have you tried reinstalling Windows?

    Posted 10 years ago #

  3. steveo
    Member

    Have you tried turning it on and off repeatedly hundreds of times per second?

    Posted 10 years ago #

  4. Uberuce
    Member

    Maybe it just needs a makeover. Vertical stripes are very slimming.

    Posted 10 years ago #

  5. Cyclops
    Member

    I've had this before and it was caused by the spade connectors not being pushed firmly enough onto the dynohub. Road vibration caused the connection to come and go so one minute the light would be working properly, the next standlight only and then back to working normally again. It took me a while to diagnose as the spade connectors weren't loose, just not shoved home firmly enough.

    Posted 10 years ago #

  6. Wilmington's Cow
    Member

    "It took me a while to diagnose as the spade connectors weren't loose, just not shoved home firmly enough."

    Yeah, that's one of the things I checked last night, because the problem seemed exacerbated by rough surfaces, so figured a loose connection somewhere, but nothing doing... :(

    I think someone needs to get the nurse again for Mr Uberuce...

    Posted 10 years ago #

  7. Instography
    Member

    Have you checked the connection at the wheel? I had a similar problem caused by a build-up of road crap around the wheel connection. Took it all apart, cleaned it up etc. Then smeared Vaseline over it. But that's a different story.

    Also, are the wires long enough at the wheel to go through the little holes, down across the terminals and then fold back up on the other side of the thingy (more precise terms are probably available). This exerts a lot of pressure on wire when the grey thing is pushed on, holding everything in place.

    Posted 10 years ago #

  8. kaputnik
    Moderator

    you might have a slight break in the wires where they are either pinched or bending at an angle. Road vibrations and extreme angles of handlebar turning might exacerbate this. I'd check the cabling from hub to light with a multimeter.

    I once accidentally tried to remove the wheel without unplugging the dynamo, and yanked the connector apart (but the break was hidden by the neck which seals the connection). It all went back together but I needed to trim down the wires and make new contact surfaces.

    Posted 10 years ago #

  9. DaveC
    Member

    I'd suggest getting the PCB solder redone, but it will void your warrenty and this should not happen, and I'd be thinking about getting a refund.

    I've got three B&M lights. Once Cyo and two Lyts. I broke one lyt when I tried a battery with too high a voltage. I managed to get some replacement components but have yet to repair the PCB.

    Posted 10 years ago #

  10. Wilmington's Cow
    Member

    PCB? I'm assuming P(?) Circuit Board? Need to work out how to open them up!

    Actually, given I got the replacement I've got aspare cable, so I'll try that before anything and see if it's kaputnik's suggestion that's the winner.

    Posted 10 years ago #

  11. wingpig
    Member

    Printed. Were you not taught that one at school?

    Posted 10 years ago #

  12. Wilmington's Cow
    Member

    Nope (got an A in Physics too - though I was good at the maths side).

    Posted 10 years ago #

  13. wingpig
    Member

    Don't know if physics would have included a mention. Did you do any craft/design/technology sort of thing? A component of that was compulsory for us in pre-GCSE years, including using a primitive BBC computer program for designing PCB pre-etching masks instead of the previous draw-a-mask-by-hand-using-a-marker-pen-on-acetate method.

    Posted 10 years ago #

  14. Darkerside
    Member

    I would ignore Uberuce; he's probably still jealous about your bike's name plate...

    Posted 10 years ago #

  15. LaidBack
    Member

    WC I have an extra B+M IQ Fly you could borrow to prove that the connections are ok...

    Posted 10 years ago #

  16. Wilmington's Cow
    Member

    Changed the wire last night then... flicker flicker flicker.

    I need a better backup front light anyway, so might nip to the bike shop at lunchtime. Anyway, seems the problem therefore probably lies with the light itself or the hub. Will put the non-standlight version on tonight to see what happens (thanks for the offer LB, should be okay with the second light I have) and if that flickers then possibly the hub.

    Sigh.

    Posted 10 years ago #

  17. DaveC
    Member

    Want to meet up after work one evening to pop my front dynamo wheel into your forks? This could help to isolate the problem? Same with your wheel in my forks as my lights have never had any problems.

    Posted 10 years ago #

  18. kaputnik
    Moderator

    Or just do it on Friday morning at PY?

    Posted 10 years ago #

  19. Wilmington's Cow
    Member

    Worth trying Friday (if I haven't diagnosed it by then).

    Posted 10 years ago #

  20. rbrtwtmn
    Member

    My best recommendation with a non-working dynamo is to disconnect everything from everything, and then to use a voltmeter to check for conductivity between things where there should be conductivity, before connecting each separate section of the system to something independent... dynamo to a separate bulb, lights to batteries, and so on. Trying to diagnose issues with things connected is nearly impossible. This is super fiddly, but it does work.

    Have to say I've sworn by dynamos for so many many years (20ish) but the balance recently tipped. With good lights now being so bright and so light, and dynamo connection/traction issues being so irritating, I've given up. Would only now consider for some kind of long expedition where batteries or power weren't available.

    Posted 10 years ago #

  21. Instography
    Member

    Really? I love my dynamo. I mean, not criticising or anything but just for sheer convenience, for never having to wonder if the lights will go out, I'm changing every bike to dynamos.

    Posted 10 years ago #

  22. Wilmington's Cow
    Member

    Sigh. Flicker flicker on the way home. Then long periods with it on fine. This morning flicker flicker as I set off, then again, about 3 miles of working perfectly. Only I get to work and see the tail light isn't lit, not even standlight. All connected up fine.

    So now wondering if actually there's something in the connection to the tail that's causing the problems. I wish I knew what I was doing. Going to disconnect the tail (got an excellent backup battery rear) and see what it's like riding home tonight.

    Posted 10 years ago #

  23. kaputnik
    Moderator

    @WC - funny you say that, when I connected my tail light (B&M Seculite) to the Cyo, the switch in the Cyo stopped working correctly, so the light is now always on, and the switch only operates the front standlight.

    Posted 10 years ago #

  24. kaputnik
    Moderator

    For a town bike, I also like having my lights bolted and wired onto the bike, for the convenience of not having to unclip so much stuff just to pop into a shop.

    Posted 10 years ago #

  25. DaveC
    Member

    @ Kaputnik - sounds like your light is not wired up properly!

    I have a battery pack for my 'other' bike without the dynamo hub wheel. I initially connected it to the rear standlight then out of the rear to the front. I could only switch off by disconnecting the battery. I now have a tri bag (linky) and put the battery in there connected to the front. The rear is connected to the front out of the output of the Cyo. Now my front light switch turns on/off both lights together.

    Posted 10 years ago #

  26. kaputnik
    Moderator

    sounds like your light is not wired up properly!

    I thought this, but given there's only 2 wires to connect, from factory-installed clips at 1 end to the rear light clips at the other I can't figure out how this could be! Dynamo light wiring seems to be a dark art for those of us who have forgotten our Higher physics microelectronics.

    Posted 10 years ago #

  27. DaveC
    Member

    @Kappers

    "when I connected my tail light (B&M Seculite) to the Cyo, the switch in the Cyo stopped working correctly, so the light is now always on, and the switch only operates the front standlight."

    Re reading this it sounds like you may have the ires the wrong way round on the rear light. The capacitor which charges and maintains the light when you stop may be then also keeping the front on - if I have understood your description.

    Its nothing to do with Higher Physics, as I never did Physics at school.

    Posted 10 years ago #

  28. kaputnik
    Moderator

    @DaveC I'll give it a shot. The light never said there was any specific way round to put the wires, especially considering the pair coming out of the light have identical housings and no markings on them to differentiate one from t'uther.

    Its nothing to do with Higher Physics

    It is if it's your only training in practical electronics!

    Posted 10 years ago #

  29. minus six
    Member

    I snapped a Luxos rear light factory connector the other day, and it is now connected up with blu tac.

    I've got a cheap soldering kit somewhere but worry that I might just make things worse with an amateur solder job...

    Posted 10 years ago #

  30. DaveC
    Member

    "the pair coming out of the light have identical housings and no markings on them to differentiate one from t'uther."

    This pdf suggests the lead from the Cyo IQ with the white / or white stripe is the ground. The Black carries the current.

    Posted 10 years ago #

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