Could having just one bad capacitor prevent a monitor from turning on?

Discussion in 'Peripherals' started by BigToque, Feb 6, 2013.

  1. BigToque

    BigToque Lifer

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    I happened to find a Viewsonic VE910B LCD monitor just sitting on the side of the road with a bunch of other garbage. I figured I'd take a look and see if there was anything I could do.

    When you plug in the power, The status LED turns green for about a second, then just goes black. The power button doesn't seem to do anything.

    I took the display apart, and looking at the board, I can see only one 470 uf 16V capacitor that looks like it could be blown. I can't see anything else on the board that could be suspect.

    Could just one small cap like this prevent the unit from turning on? I kinda figured I'd be seeing a bunch of blown caps. Because it's just one, I'm wondering if there's something else that got damaged. (I'm living on a small Caribbean island and power surges are common - unfortunately I can't really just go pick up a new cap to test it)
     
    #1 BigToque, Feb 6, 2013
    Last edited by a moderator: Feb 6, 2013
  2. thirdeye

    thirdeye Platinum Member

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    Yes, I've 2 Samsung LCD TVs fail due to this exact issue. One blown cap kept both TVs from turning on, and simply replacing the cap with a new one, fixed the issue.
     
  3. Eureka

    Eureka Diamond Member

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    Just pick a cap with similar specs and replace. Chances are it's just on the power supply for filtering. Doesn't have to be the exact cap, I think I replaced a blown one on mine with one of a slightly different value. Match the voltage, and match the capacitance within 10%.
     
  4. BigToque

    BigToque Lifer

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    Since it's a PITA to get things here on the island, I've just been keeping my eyes open for any electronics people throw out. I've pulled a few circuit boards out of some random things and here's what I feel my best options are (assuming I don't find an exact match - which is 470uf 16V).

    470uf 25V
    1000uf 16V

    I'm reading mixed things now about which cap I should use. Some say use the same capacitance and slightly higher voltage, others say capacitance can be higher as long as voltage is the same.
     
  5. Wall Street

    Wall Street Senior member

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    Use the same capacitance higher voltage. The voltage rating is the maximum voltage that it can take, higher voltage capacitors look that same in the circuit diagram. Increased capacitance can be OK if the cap is just meant to store power, however, if the circuit calls for a specific capacitance it could get nutty if you use a different value. Also if the capacitor being replaced isn't electrolytic (the cylinder shaped ones) than you need to replace it with a capacitor of the same make. Finally, most electrolytic caps are polar, if you install the replacement backwards, it will immediately blow.
     
  6. styrafoam

    styrafoam Platinum Member

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