LCD Monitor Power Supply Question

Discussion in 'General Electronics Chat' started by works4me, Feb 16, 2012.

  1. works4me

    Thread Starter New Member

    Feb 16, 2012
    1
    0
    Repairing a 24" Soyo Topaz Monitor that has a bad power supply. Unable to locate replacement parts I'm attempting to replace the manufacturers PS with a Meanwell RT-65D baised on the sucess of another person in the following thread Post #94.

    http://slickdeals.net/f/1655449-Solved-How-to-fix-M24E14-M24EI4-power-supply-board?&page=7

    Soyo PS Connectors

    http://slickdeals.net/forums/attachment.php?attachmentid=316463&d=1263464291

    The Meanwell has an earth ground connection and a common for the three different output voltages. Should the GND connection on the Meanwell RT-65D be jumped to COM and then connected to Soyo GND??

    http://www.mean-well.com.au/shop/79-2483-thickbox/-rt-65d.jpg

    Any help would be appreciated.
     
  2. Felo

    Member

    Feb 20, 2012
    91
    13
    Hi,

    The most of my experience with LCD's says that the power source almost NEVER get too blown or has a major fail beyond simple repair and common component replacement.

    If you feel like getting your hands dirty follow these simple steps.

    Let's see if i can help.

    1- put your ear near the circuit (not too close or you will electrocute you ear lobe, not a good feeling), connect the mains supply on the PS, you should hear a "click" or a sparkling sound. If you heard it half of the PS is in good working order and you should be happy. goto step 3

    2- If not heard, and the circuit "looks good", meaning no obvious component destruction or swelling or cracks or overheating signs, etc. look for the primary electronic proteccion devices in the input stages of your circuit. this may include fuses, movs, diodes etc.
    replace as needed.

    3- The output stage of a SMPS is the "other side" of the mains input stage, commonly separated galvanically by a large inductor, there will be some relatively small caps, let us say in the range of 22 to 100uf / 25 to 50 vdc, normaly in pairs. like series connected. Replace these caps with good quality and most important "LOW ESR" ones it doesn't matter if they are no the exact same, just do not go lower on the VDC rating, more is better here.

    Following these simple steps, you will fix 90% of failed SMPS, remember to be safe and aware of large voltages stored in capacitors wich could kill you or completely discourage you to keep trying to fix it..... let us know how it goes.

    Good luck.
     
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