Monitor will not turn on. Does it have a fuse I can change?

Discussion in 'PC Hardware' started by B__P, Aug 5, 2010.

  1. B__P

    B__P Guest

    I've a 22" Westinghouse LCD Monitor that stopped working from one day
    to the next. The light the normally comes on when the monitor is on
    doesn't even light up. Could it be that a fuse has blown on the
    inside? Maybe one I could replace? Or perhaps the on/off switch
    has gone bad. If anyone can provide a credible reason it stopped
    working and a possible fix, I'd be most grateful.

    BP
     
    B__P, Aug 5, 2010
    #1
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  2. B__P

    GMAN Guest

    Could be a fuse, but could also be a ton of blown or bulged capacitors inside.
    If you dare and are good with a soldering iron and a desoldering tool, go
    ahead and open it up and look. I repaired a Acer 24" monitor that was 2 weeks
    out of warranty. I had to replace 18 capacitors of differing ratings, but it
    works like day one now.
     
    GMAN, Aug 5, 2010
    #2
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    Mike Easter Guest

    The Westinghouse LCM-22W2 manual doesn't provide any user service advice
    in its troubleshooting for no power except to be sure that the monitor
    AC cord is plugged in to the back and the wall and that the wall plug
    has power.

    Even with no vid signal, the power light is supposed to be orange, green
    when operational

    I don't think you can pay to troubleshoot it and replace something for
    the price of replacement.
     
    Mike Easter, Aug 5, 2010
    #3
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    GMAN Guest

    Definately would cost more to pay someone else to fix than to just buy a new
    24"-26" for around $200 or so. But like i said, if you know how to solder ,
    a blown fuse , if its that, would cost all of a few dollars if that, and even
    if every capacitor in the unit is needing replacement, it most likely wont
    cost you more than $10-$15 for those parts.
     
    GMAN, Aug 6, 2010
    #4
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    John Doe Guest

    But seriously. That is neither here nor there.
    --
     
    John Doe, Aug 6, 2010
    #5
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    Paul Guest

    It helps if you have a model number to work with. The following
    is just an example I made up for myself :)

    *******

    I can't see a fuse here. Just a moderately dangerous open-face
    assembly to work on (yellow PCB).

    http://www.ccl-la.com/blog/index.php/repairing-the-westinghouse-lcm-22w3/

    http://i.ebayimg.com/15/!Bud)9zgCGk~$(KGrHqQOKigEvN2wjNhrBM!eFK8N2Q~~_1.JPG?set_id=880000500F

    I'm guessing, signal flow, left to right, bottom half, is
    AC input filter, rectify to HV DC, switching transistor on heatsink
    for HV primary side DC, transformer in yellow, with turns ratio to
    fix output voltage, rectifiers on heatsink (synchronous rectification,
    or just plain rectifiers ?), and a bunch of filter caps for low
    output voltages. Eight pin connector carries low voltages
    to the adapter board (adapts DVI and VGA, to panel signals,
    does scaling perhaps).

    The top section includes two HV inverters, taking perhaps 12VDC
    in and giving 700-1000 VAC output at high frequency, to run the
    backlights. I see perhaps two optoisolators (8 pin) ? And the
    three yellow things on the right could be small transformers,
    not really sure what that would be for.

    Depending on the era, the capacitors could be leaking, and the
    unit may have managed to detect an internal overload, shutting
    down the switching action.

    It could have a fuse, as I can't identify every component in the picture.
    For example, there is a black blob below the three pin AC plug. The
    PCB assembly is really cheap, and appears to be a single sided layout,
    with wire straps used on the component side, to complete the layout.
    Rather than put copper tracks on both sides of the PCB, they put
    most of the copper tracks on the back. When a signal needs to
    jump, they use those bare exposed straps on the component side.

    The supply board is made by Delta Electronics. And that particular
    example is DAC-19M009. The only thing I can see on Ebay, is someone
    offering to accept your power supply board, and replace the
    caps for you. Even though there could be other damage to the
    thing. It isn't always going to be just the caps that
    are damaged. When caps fail, sometimes other components
    are damaged in collateral action.

    Any sizzling, smoke, or funny smells before this happened ?

    The thing is, even if there was a fuse, that fuse blew for a reason.
    Just replacing the fuse won't fix it. The fuse would only blow again,
    until you fixed it right.

    It is possible for an engineer, to use a wrong value fuse, leading
    to nuisance trips. But I haven't seen a mistake like that in
    eons. Most of the time, the fuse will blow, to tell you there
    is a serious problem elsewhere. A problem that must be fixed
    first, before you can contemplate changing the fuse.

    Paul
     
    Paul, Aug 6, 2010
    #6
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    Mike Easter Guest

    That's a useful description to help sell his package of capacitors.
    One of the comments had a fuse, the tech guy answered that there are two.

    Comments 5 & 7 - the numbering system is imperfect w/ dupes

    =========

    # Peter Triffitt on Wed, 17th Mar 2010 4:03 pm

    Hello Sirs.
    What a brilliant site!! My monitor has just stopped working, no
    noticable warnings.I have the board DAC-19M009 on my bench, and it all
    looks in order. But I have tested the fuse (F101) and it is open
    circuit, there is also a very slight area of soot between the fuse
    connections. Shall I replace the capacitors anyway? Can you supply the
    fuse? Or is this a different fault?
    Best Regards Pete.

    # CCL_TECH on Sun, 21st Mar 2010 3:55 pm

    Yes, We can provide the fuse. Which fuse is blown, the one on the ac
    side or the pico fuse on the bottom of the board?

    =========

    Further down there is more description about that fuse.
     
    Mike Easter, Aug 6, 2010
    #7
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    Astro Guest

    Where is it?
     
    Astro, Aug 6, 2010
    #8
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    Paul Guest

    I didn't even notice the comments section :)

    I see one comment in there:

    "I ordered a replacement fuse, and replaced the bridge rectifier too,
    but it popped right away again. Does that mean I should do the
    capacitor kit now?"

    That is what I'm talking about. The fuse isn't the cause of the problem,
    it is a symptom. It tells you something else is cooked.

    I also liked the description, where a poster said their transformer
    was running hot. So who knows what other things can fail on that
    power board.

    The thing labeled as a picofuse, could be a polyfuse. But because the
    picture is out of focus, it's really hard to say what it is. My
    experience with picofuses, is they blow easily, and my buddies used
    to multiply the rating a fair bit, to keep them going. (I.e. Use a
    10 amp pico in a 2 amp circuit.) And even then, they weren't super
    reliable. So we used picos on lab prototypes, to prevent stuff
    from burning up - if one popped, it didn't take long to fit another
    one. But sprinkling them in a production circuit would be another
    matter. Fuses are bad in any case, and generally, they're installed
    when you need some kind of certification. It you were to put them
    into a circuit "because you were nervous", the warranty claims
    coming from the field, would be never ending. The boss would probably
    make you solder in all the warranty replacements, as punishment.

    Paul
     
    Paul, Aug 6, 2010
    #9
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    Jon Danniken Guest

    Somewhere over the rainbow?

    Jon
     
    Jon Danniken, Aug 6, 2010
    #10
  11. I have seen a large number of monitors fail by perpetually going into
    standby. There's no question it's the monitor as the monitor will
    fail no matter what PC and a different monitor will work on the PC.
     
    Loren Pechtel, Aug 6, 2010
    #11
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    VanguardLH Guest

    Okay, back to the basics. Did you actually check the power cord was
    plug in (to BOTH the monitor and into a wall socket or power strip)?
    Have you tried wiggling both ends of the power cord to check if it is
    fully inserted or has intermittent connections? If not plugged into a
    wall socket and instead into a power strip, UPS, or something else, did
    you unplug the cord and try a wall socket? Did you plug something ELSE
    known to work into that same wall socket, like a lamp with a good bulb?
     
    VanguardLH, Aug 6, 2010
    #12
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    Strobe Guest

    Some fuses do indeed blow just from old age.

    I've recovered 'dead' Trinitron monitors from the NYC sidewalk just by replacing
    the failed slow-blow fuse in the input line. After 18 months one's still
    working great, the other is in reserve waiting its turn.
     
    Strobe, Aug 6, 2010
    #13
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    John Doe Guest

    Nooo! He has to replace all of the capacitors in his monitor.

    Outrageous. Apparently some people are really bored.
     
    John Doe, Aug 6, 2010
    #14
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    VanguardLH Guest

    It's obvious you have never had to help others and only yourself.
    Otherwise you'd experience users calling in with a dead monitor who
    happened to kick the plug out of the socket when they were moving their
    feet under their desk, or the boob that calls in to report a dead
    monitor but it's too dark to see behind the work desk because there's a
    power outage in their area.
     
    VanguardLH, Aug 7, 2010
    #15
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    John Doe Guest

    That was supposed to be sarcasm.
    That is entirely possible, but we may never know.

    Actually I was bashing the other suggestions. Without knowing
    anything about the original author or the monitor in question,
    telling some stranger that he might need to replace all of the
    capacitors in his monitor because it does not turn on sounds very
    strange to me.

    Not enough activity in this group lately.
    --
     
    John Doe, Aug 7, 2010
    #16
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    VanguardLH Guest

    You somewhere in my reply - the one to which you replied - any mention
    of capacitors? I figured you were berating me with the "really bored"
    comment since it was to me that you replied.
     
    VanguardLH, Aug 7, 2010
    #17
  18. B__P

    GMAN Guest

    No, just frugal. I had a perfectly working and beautiful 24" monitor go out on
    me, and i'll be damned if i was going to throw the thing out just because $10
    in capacitors went out in it. Like i said, for someone like me who can mil
    spec solder almost blindfolded, it was a nobrainer to fix and i was able to do
    the desoldering and resoldering job with 12 capacitors in a matter of 20
    minutes. But its not for the faint of heart.


    Why would i want to throw away a $300 monitor?
     
    GMAN, Aug 7, 2010
    #18
  19. B__P

    GMAN Guest

    I never said that. I said basically that its a common thing for LCD monitors
    to fail that way. And its not always the whole monitor. Mine just happened to
    be built with those cheap knockoff ones that bulged. At the very least , while
    the OP has his monitor apart to look for a blwon fuse, he should at the very
    least look at the power supply capacitors.

    Just because you may not be capable of the task, quit shitting on other
    peoples skills. The OP may be very capable of the task.

    More people leaving their basements?
     
    GMAN, Aug 7, 2010
    #19
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    John Doe Guest

    Someone comes in here and asks about a blown fuse or a faulty
    switch, and you suggest he should replace all of the capacitors in
    his monitor. Besides not really knowing anything about the
    original poster or the condition of his monitor, you do not even
    know if his monitor is still under warranty.

    That is just silly.
    Not likely.
    --
     
    John Doe, Aug 7, 2010
    #20
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