Syncmaster 206bw blinks on and off

syncmaster 206 bw blinks on and off
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More about syncmaster 206bw blinks
  1. Same problem here :)
    Seems to get better once the monitor warms up.

    I Suspect that this is a fault in the power supply/ inverter circuit,
    probably due to a leaky electrolytic capacitor. The ON/OFF switch
    or the power LED has nothing to do with it.

    Computers, Monitors, Televisions (and most other modern appliances) no longer
    use mechanical ON/off switches, in favor of an electronic circuit based on
    digital logic and a relay.

    The monitor has two separate power supplies:

    1) An ultra-low power supply circuit which is ALWAYS on.
    This circuit provides a small amount of power to the digital
    logic chip which in turn controls the MAIN power supply through
    a relay or some other form of indirect switching.

    2) The main power supply, which provides operating power to the rest
    of the monitor.
    --
    Both power supplies contain one or more of the following components:

    a) A transformer (or external AC adapter) which provides electrical ground
    isolation from the incoming AC line for safety reasons

    and

    reduces the operating voltage from 117 Volts AC to a lower and safer
    level (e.g. 12 volts for internal consumption by the monitor).

    b) A rectifier, which converts AC to DC.

    c) Filter capacitors to smooth out the resulting DC.

    d) Voltage regulators to make the DC more constant and precise.

    e) The circuit may also contain over-current, over-voltage or other
    automatic fault detection to protect the monitor from catastrophic
    failure.

    f) The monitor may also detect the lack of video input and automatically
    shut itself of after a few minutes.
    --
    The reason I am telling you all this, is that the power supply control
    logic in a modern monitor can get very complicated, but fortunately
    these circuits a quite reliable, and not a typical cause of failure.
    Also the entire circuit is typically implemented in a single silicon
    chip with very few external components.
    --
    The one weak link in the system are the filter capacitors, which
    consist of two sheets of ultra-thin metal foil wound up in a spool,
    separated by some sort of an ultra thin insulator.

    The larger the area of the two foils and the thinner the insulation
    between them, the higher the capacitance:
    i.e. the better the filter.

    In the case of modern electrolytic capacitors, the insulation is only
    a few atoms thick, often created by a chemical reaction between the
    metal foil and special fluid bathing the spools. The whole thing looks
    like a tiny, narrow but tall can of sardines.

    For this reason, electrolytic capacitors are also polarized +/-.
    If you insert them backwards into a circuit, they will explode
    (literally !)

    In the case of solid tantalum capacitors, which look like a tiny
    teardrop with two leads coming out of it, this explosion can
    be very loud and violent, like a shot-gun going off. The capacitor
    gets totally vaporized, nothing left except two leads sticking out
    of the circuit board, where the capacitor once was. I suppose that
    the shrapnel an debris could severely damage your eyes on
    a bad day. When ever I power up a circuit board, I always look
    the other way.

    If these capacitors are operated too close to their maximum
    voltage or if they are overheated during normal operation,
    the thin insulating layer will fail, resulting in leakage current.
    The voltage will drop and the monitor will not work, or the
    power supply control logic will detect the fault and fail to
    operate.

    Similarly, if the monitor is not used for a long time, the lack
    of voltage will cause these capacitors to dry out.
    Once again the insulating layer will fail.

    Sometimes, a defective capacitor is obvious:
    1) It is totally gone, exploded, vaporized right off the circuit board.
    2) It is swelled up and leaking.
    3) It is discolored...

    But many times there is no physical indication at all!

    In this case you need to get a service manual or at least a schematic
    for the monitor and measure a few voltages around the power supply
    circuit. This requires a good voltmeter, and perhaps an Oscilloscope.
    The former is cheap, the later very expensive.

    Ultimately you need some knowledge of electronics to identify
    the bad capacitor, so you can replace it. Then you need good
    soldering skills. The capacitors them-selves, are standard parts,
    easily available, and dirt cheap.

    If the monitor starts working after a while do NOT shut it off.
    The capacitor may heal itself.
    Good luck.
  2. It's caused by three bad capacitors. See the site for fixing it yourself. http://normsweb.com/tektips/sam206bw.shtml.

    I just fixed mine last night. It works now like a new one.

    Purchase the three capacitors at www.futurlec.com
    (2) 1000uf 25v Radial 105oC Electrolytic Capacitor 2x$0.35 = $0.70
    (1) 470uf 25v Radial 105oC Electrolytic Capacitor 1x$0.20 = $0.20
    Shipping from Thailand (It only took about a week to reach St. Louis, MO) $4.00

    Buy a soldering gun from Amazon.com, it comes with a coil of solder
    Weller SP23LK Marksman 25 Watt Soldering Iron Kit = $14.55 w/ 7-years warranty
    Shipping is free if your total purchase is over $25 with other items you need on the Amazon.

    Therefore, your total cost is less than $20 USD. It will enable you to fix the problem once for all.

    I noticed that the soldering gun need to be switched with a flat head first, (it comes with in the package), in order to soften the existing solder to remove the old and blown-off capacitors. Then switch back to needle style head at soldering gun to weld the new capacitors in place.

    Please note that existing soldering is hard to be softened. You need to be patient to place the flat head soldering gun for a quite long time. The existing solder will be melted. At first I thought my gun is not hot enough to melt the old solder. So, be patient.
  3. See if this helps:

    http://www.tomshardware.com/forum/58596-3-official-flat-panel-repairs-thread

    Good idea to invest in a cheap solder pump for removing components -- reduces the chance of damaging the circuit board.
  4. HelpallHelpone said:
    It's caused by three bad capacitors. See the site for fixing it yourself. http://normsweb.com/tektips/sam206bw.shtml.


    Hello I'm norm from normsweb.com. you have an error in the link to my samsung 206bw repair page.

    The correct link is http://www.normsweb.com/tektips/sam206bw.shtml

    and not http://normsweb.com/tektips/sam206bw.shtml. I hope that people trying to locate the page will be able to find it easier now.
  5. hi, the link doesn't work anymore, is it possible for you to send me a picture of the board with an indication of the defective capacitors? (i'm asking that, beacause i guess this picture was on the page). I'd like to repair my screen, i have no money to buy a new one and this one do a great job!

    Thank you!
  6. The link does work, just make sure that you do not have a full stop . at the end of the link. (eg: .shtml not .shtml. )

    if you still cant get there, goto normsweb.com, click on tektips, and scroll down to the 206BW link and click it.
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