Samsung SyncMaster 740N 17" LCD Monitor Logo
Anonymous Posted on May 10, 2010

Dark Screen, unreadable. Power Led Lights. No noticle sounds.

Screen had slowly grown progressivelt darker. Is now unreadable. When computer id off the power LED blinks. When the computer is turned on the power LED is continuous. No buzzing nor any aother sounds.

  • 1 more comment 
  • Anonymous May 11, 2010

    Thank you for your very helpful reply. I claim no experise at electronics but can stumble my way through most things.

    I've since discovered there is no power to any of the four backlights. The capacitors look ok (but what do I know), so will start exploring the power inverter.

    Thanks.

  • Anonymous May 11, 2010

    Thanks a million. There appears to be three bad capacitors. The link to the Service manual is a BIG help.

  • Anonymous May 11, 2010

    Now I'm trying to find new capacitors: Samxon 820uF 25V. I've found a complete power card on Ebay but it's pricy. I'm waiting to hear from Badcaps. That is a GREAT site.

    Thank you.

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1 Answer

Bud Martin

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  • Master 11,361 Answers
  • Posted on May 11, 2010
Bud Martin
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If you are going to DIY repair, please read below and look at the pictures of failed SAMSUNG monitors (bad caps with bulging tops)
Most common failures in the LCD monitors are bad capacitors (bulging top/seal or leaking) in the power supply, failed inverter circuits (blown fuse, shorted transistors, shorted/open transformers), bad lamps (poor solder connections or worn out lamps). You will need to open it up and inspect the inside, see example of failed monitors to get some ideas what to look for: http://s807.photobucket.com/home/budm/allalbums
Post back what you see inside so we can guide you further and it will help out other people in the future also.
http://en.wikipedia.org/wiki/Capacitor_plague

http://www.badcaps.net

Testimonial: "Good links! Thanks."

  • 1 more comment 
  • Bud Martin
    Bud Martin May 11, 2010

    Here are the free service manuals if you really want to dig deeper:

    http://elektrotanya.com/?q=showresult&am...



    Any caps with slightly bulging will be bad caps.

  • Bud Martin
    Bud Martin May 11, 2010

    I hope you can fix it and nothing else are damaged due to bad filter caps.

    Can you please send me the pictures of the board so I can post them to help out people with the same problem?

    [email protected]

  • Bud Martin
    Bud Martin May 12, 2010

    You should replace more than just those 3 bad pne for the inverter circuits, the other smaller one for the 5vdc supply should also be replaced at the same time. PANASONIC FM or FC series from Digikey will be good to use. Just give me the other caps that are close to those 3 bad one and I will give you the Digikey P/N, should not cost more than $15 total (parts + shipping)

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Most common failures in the LCD monitors are bad capacitors (bulging top/seal or leaking) in the power supply, blown fuses, failed inverter circuits (blown fuse, shorted transistors, shorted/open transformers), bad lamps (poor solder connections or worn out lamps). You will need to open it up and inspect the inside, see example of failed SAMSUNG monitors to get some ideas what to look for: http://s807.photobucket.com/home/budm/allalbums
Post back what you see inside so we can guide you further and it will help out other people in the future also.
http://en.wikipedia.org/wiki/Capacitor_plague

http://www.badcaps.net
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