Christmas lights killing power adapter

Discussion in 'General Electronics Chat' started by doby, Dec 20, 2014.

  1. doby

    Thread Starter Member

    Aug 17, 2011
    I've got 2 sets of the same lights (240 rice (incandescent) lights, 24V) and both became faulty at the same time. They turn on as expected but after a short while kill the power adapter. I'm presuming it's something in the multifunctional box which controls the different sequences of flashing.

    Any idea would could be causing this? A faulty diode perhaps?
  2. Lundwall_Paul


    Oct 18, 2011
    Almost sound your adapter just doesn't have the current capacity. Do the two set run ok individually?
  3. wayneh


    Sep 9, 2010
    Are we are to guess about the model of adapter and its specs?
  4. doby

    Thread Starter Member

    Aug 17, 2011
    They're both powered individually, sorry I should have made that clear. The reason I said 2 sets is because they're identical and became faulty at the same time which suggests they have developed the same fault.
  5. doby

    Thread Starter Member

    Aug 17, 2011
    Well the adapter was supplied with the lights and worked for 2 years without issue so I didn't think it was relevant because I believe the fault is with the lights themselves. When the first adapters died I did originally think they were the cause but after replacing them they also died within a matter of hours.

    Here you are anyway

    Model No. JT-650
    230-240V ~ 50Hz
    24V~650mA Max: 15.6VA
    Last edited: Dec 20, 2014
  6. KJ6EAD

    Senior Member

    Apr 30, 2011
    Made by Changzhou Jutai Electric Co., Ltd. and you have difficulty believing that the transformer could fail immediately?

    It's just a transformer and probably a thermal fuse that is opening. If it were mine, I'd probably cut open the first one that failed out of curiosity. Wayne may not be so brave since he apparently has alien cats and everyone knows that curiosity and cats should not combine.

    So you have a 24VAC supply that apparently failed while supplying power to a controller of two small light sets after a long history of operating correctly. A replacement supply quickly failed as well. This suggests a low impedance fault within the controller (a short).

    The standard response is to throw the offending device into an e-waste container and buy a replacement but if you're interested in diagnosing the fault, detailed photographs will be needed.
    Last edited: Dec 20, 2014
    wayneh and Lundwall_Paul like this.