Switching Power Supply cannot power up

Discussion in 'The Projects Forum' started by welcomb, Oct 11, 2009.

  1. welcomb

    Thread Starter New Member

    Feb 18, 2009
    5
    0
    My router's DC adapter just died, so i went and bought a switching power supply from a local computer store. It requires a 5V 2A source which the power supply is rated to handle.

    However when I plug it into my router and turn it on, the power supply LED flickers along with my router's LEDs, as though the power is being turned on-off quickly. Since my router doesn't have a power switch, when I unplug the power cable from my router, and turn on the power supply first, then plug into the router, it works fine.

    The power supply should have some capacitor since when the mains are turned off when it's unconnected, the LED still remains on. Could it be that this keeps the voltage cycling since my router would be draining the capacitor before it fully charges? Any ideas how I can fix this?
     
  2. MacTaufan

    New Member

    Oct 12, 2009
    2
    0
    hi,
    it seems that your power supply needs times to boot up to charge the capacitors before it's ready to supply power to the router, and i think your router takes up maximum power the PS can supply. I might not fully understand about the working concept inside your PS, but it's good to make a delay circuit between the two devices. it could only need 1-3 seconds delay, so it could simply a relay, transistor C9013, and a 1000uF electrolite capacitor. CMIIW
     
  3. bountyhunter

    Well-Known Member

    Sep 7, 2009
    2,498
    507
    That's a typical symptom of over current limiters kicking in and out.
     
  4. welcomb

    Thread Starter New Member

    Feb 18, 2009
    5
    0
    My power supply has a voltage selector switch and is rated 2500mA at 5V, which my router only needs 2A. So is the over current limiter is kicking in before the power supply stabilizes? What simple circuit can i build without resorting to buying a new supply?

    Btw the Newstar NSC-17 (http://kinmopw.com/products/newstar/switching.html) cost about $26.
     
  5. welcomb

    Thread Starter New Member

    Feb 18, 2009
    5
    0
    no one has any remedy? no simple circuit i can put in between?
     
  6. Demento

    New Member

    Jun 26, 2009
    2
    0
    Sounds to me like your supply is running in discontinuous mode. Is there a minimum load requirement for your power supply?
     
  7. gerty

    AAC Fanatic!

    Aug 30, 2007
    1,153
    304
    There could be a problem inside your router that caused the original power supply to go bad, causing it to draw more current than it should.
    Is there a way you can measure the current being drawn by the router and see if it's within specs?
     
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