G4 LED bulbs buzzing and flickering

Discussion in 'Electricians' Talk' started by greenback78, Feb 15, 2020.

  1. greenback78

    greenback78 Active Member

    As 3 out of 5 halogen g4 bulbs in a fitting had gone I decided to replace all 5 with new LEDs. Went with Philips as they tend to be more reliable than the no-name Chinese brands. Unfortunately the bulbs are making a buzzing noise which gets progressively worse before starting to flicker badly. Any ideas what could be causing this? Seems off and assume it’s related to the fitting (less than 10 years old). Thanks.
     
  2. Philip Hyde

    Philip Hyde Active Member

    Do you have a dimmer on the circuit?? If so it's probably that. Needs to be trailing edge dimmer for LEDs
     
  3. greenback78

    greenback78 Active Member

    No. No dimmers anywhere and other LEDs in the house are working fine.
     
  4. Are they 12volt or 240 volt.
    If 12 volt they may not be compatible with the transformer, or not enough load for the transformer and need a compatible driver fitted for the load.
     
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  5. Philip Hyde

    Philip Hyde Active Member

    Yeah good point I read G4 as Gu4 o_O
     
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  6. greenback78

    greenback78 Active Member

    12v as far as I can see from the description. Will check the fitting and see if I can replace the transformer. Thanks for the advice.
     
  7. greenback78

    greenback78 Active Member

    Ok so I’ve managed to source a transformer that will sufficiently power the leds but I must admit I’m baffled by the wiring of both the original transformer load wiring and the colours of the supply side wiring on the transformer. Transformer came from Germany. Photos attached if anyone can advise on how to match the wiring correctly without ruining the transformer. Thanks!
    3BFFF922-50DD-4522-B151-2E664153D4DD.jpeg E97C6B17-A6B9-45B1-BC97-0890948B3641.jpeg A44F46C2-F128-463C-A6E5-EC1E5F127C1B.jpeg
     
  8. greenback78

    greenback78 Active Member

    Scratch that. Worked it out myself courtesy of dr google. One functioning light fitting! Thanks for the advice.
     
  9. MGW

    MGW Screwfix Select

    What do the bulbs say, original power supply was AC output at kHz new one DC output, some LED bulbs are marked 50 Hz, others are DC it does depend on the bulb. Seems crazy but often nothing on the advert, only find it is AC when you see 50 Hz marked on bulb, DC versions do tend to state DC, this one clearly marked 10 - 30 volt DC but AC versions not so clearly marked.
     
  10. peter palmer

    peter palmer Super Member

    G4 bulbs are a waste of time, the pins on the bulbs are that thin that they never make proper contact with the connections in the holder and end up burning them out so even with LED bulbs you can still have problems, More often than not when a G4 halogen lamp goes out it not even the bulb thats blown and a quick wiggle gets them to light again and that's even without the issues with transformer compatibility.
     
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  11. greenback78

    greenback78 Active Member

    yep. Wouldn’t be my first choice for a light fitting. Trying to keep an existing one going with LEDs that I’d already bought so the £8 transformer was a good trade off. But I would hesitate to buy anything with G4 again.
     

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