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All lights in a fitting pulse in sync

Discussion in 'Electrics UK' started by d000hg, 13 May 2020.

  1. d000hg

    d000hg

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    I recently replaced all the LEDs in a 5-bulb fitting as the new ones we bought emitted a loud buzzing sound. The new ones are thankfully silent but I'd noticed the light level in the room fluctuates a bit.
    Looking closely, it seems all 5 bulbs are slightly dimming/brightening as one. Maybe every few seconds they get a bit brighter, 5s later a bit dimmer again.
    Just enough to be really annoying as you notice it.

    If they are all doing it together this must mean it's not a fault in the bulb? So what then? I thought maybe my electrical supply to the house, but I don't see it in any other rooms (we have LEDs throughout). Unless all my other bulbs have some smoothing and these ones don't?!

    I also replaced the old light-switch with a brand new, LED-compatible dimmer switch. Might this be the issue?

    It's the fact it 'flickers' only every few seconds I find most confusing. Any tips to diagnose and fix? I considered forcing it always on (using a connector block to bypass the switch) to see if the switch is at fault.
     
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  3. flameport

    flameport

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    What type and fitment are the LEDs, and what make/model is the dimmer?
     
  4. d000hg

    d000hg

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  5. flameport

    flameport

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    Almost certainly the dimmer.

    Get a decent one from Zano or Varilight.
     
  6. Taylortwocities

    Taylortwocities

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    LAP dimmer. :eek::eek:
    I’d suspect that. unfortunately screwfix have removed that part no from sale so cannot see the spec.

    I’m supposing that the lights don’t do this if you link the dimmer out?
    Personally I would use the Varilight V-PRO dimmer.
     
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  8. flameport

    flameport

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    It's still there, copy & paste the link.

    This forum has removed the ability to link to screwfix, because the screwfix affiliate scheme has closed.
     
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  9. d000hg

    d000hg

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    I don't really understand why they'd block links just due to no affiliate money but hey ho.

    The part is 77563 but it has good reviews. However I just noticed the max LED load is 50W. When I buy LED transformers they always seem to say you should allow 10% headroom and running 5 9.2W lights I'm pretty close. Could it be as simple as the switch is underpowered? I suppose I could check by removing one bulb and seeing if it still happens. Still have to get a different switch but knowing if the switch is crap or just underpowered might help.

    Annoyingly the Varilight is only a couple quid more, I don't know if you can still return things with CV.
     
  10. flameport

    flameport

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  11. d000hg

    d000hg

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    £50 for a light-switch?!

    Anyway since everyone seems to agree the switch is the problem, I'm going to bypass it and confirm the problem goes away. I'll either put the old non-dimmer switch back in or get a better one assuming this IS the problem.
     
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