Samsung SyncMaster 931B 19" LCD Monitor Logo
William Bross Posted on Aug 16, 2012

Samsung Monitor Backlight/Power Issue

I am able to turn the monitor on for a few seconds. Once it is turned on, the monitor displays "Analog" in the top left portion of the screen and then abruptly goes blank. If i shine a flashlight at the screen from the side, the screen still displays an extremely faint picture that it is receiving from my laptop. After some research, I found that some others have had the same issue. I replaced the following capacitors on the inverter board (C112, C113, C316). The C112 and C136 (870uf, 25V) were obviously defective and were replaced with 1000uf 35V capacitors. The C113 (470uf 25V) did not seem defective but was replaced with one rated at 470uf 35V. After reassembling the hardware, the problem was still occurring. Any advice would be greatly appreciated...

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  • Posted on Dec 08, 2012
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Hi, these mosfets are obsolete now, do you know a good equivalent for them?

Thanks

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Anonymous

  • 8637 Answers
  • Posted on Jan 09, 2009

SOURCE: Samsung GH19LS LCD Monitor wont display computer signals

You should have received two cables with the monitor. One is for VGA and plugs into you video card or computer board . The second one is for DVI digidal video and if you have that cable it plugs into the square connector. Then if you look into your monitor manual or quick setup sheet it will tell you how to connect and set the monitor to either VGA or Digital. I'm sure that is what has to be set. Don't hook up both cables to the monitor and computer. Only use the one. Digital gives you a better picture if your computer has that function. Hope this is helpful. Bud

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Anonymous

  • 53 Answers
  • Posted on Sep 09, 2009

SOURCE: Syncmaster 910t blinks image perfectly once and goes back to black

I've had same problem and I fixed it!
With good CCFLs, clean supplying voltages, all good capacitors and resoldered junctions, the backlight still turns on for fraction of second and goes off.
It is in the Power Supply / Inverter board. In the Inverter part there are two dual n/p-MOSFETS U3 and U4 (models STS7C4F30L, SO-8 packages). I've found they both have too high ON-Resistance (perhaps due to age and constant overheating). All you need to do is to replace them. I've checked many models and found closest by Rds and IDcont (continuous drain current) are IRF7389, you can find distributor by findchips.com, but I've bought them at newark.com, they're cheap.
The hardest thing was to unsolder old chips, they are glued to PCB and because of overheated material under them, the copper could easily go apart. Therefore, the best is using fine tips cutters, cut off all legs one by one and then take chip body off the PCB and take legs from pads by iron. That's all you need. After that my monitor started working as new even with old CCFLs. Good Luck!

Anonymous

  • 2 Answers
  • Posted on Oct 27, 2009

SOURCE: Monitor goes blank after 3 seconds -Samsung SyncMaster 920NW

hello i have the same problem, there are 4 lamps (bulbs) inside the monitor when some of them falls the system turn off, cheks and good look

Anonymous

  • 732 Answers
  • Posted on Dec 24, 2009

SOURCE: I have a Samsung Syncmaster 932b LCD monitor.

savato321, Most black screen lcd monitor owners don't have the smarts to open up their monitors to do a VISUAL inspection of the "switch-mode-power-supply/inverter supply!!!! You're good. Now you will need to know some stuff about electrolytic filter capacitors! First, the "uf" or "UF" means micro-farad! It is just a rating given to express the storage capacity of the device. Next is the voltage rating. A 16v rating means that the capacitor should never be placed in a circuit where the voltage will exceed 10 to 12 volts DC. Your 820 uf cap rated at 25volts will most likely be in a 12 to 18volt dc circuit. Now for temperature rating. All caps have a maximum temp rating. Most clock radios, stereos, will use 85 degree centegrade rated caps. Printers,PCs,monitors, will use 105 degree C rated capacitors. Never replace with lower specification units! You can GO up but never DOWN. If 1000uf 25v is all you can get it's OK. If you can get 820uf 35v units and they are not too big and they will fit on the board sure you can use them. I would stick with the OEM design voltage rating. Electrolytic CAPS are polarized!! You must replace them + to + and - to -!!! If you screw -up they will blow-up!! The wire lead closest to the printed STRIPE on the cap will be the negative and the unmarked terminal will be the positive. If you visit www.ccl-la.com/badcaps.htm you will get more info on recapping your SMPS. You can also watch some DIY videos at YOUTUBE for "lcd monitor repair" that might be helpful. Also visually inspect the SMPS/inverter printed circuit board for "COLD" FROSTY looking solder joints. They should all have near mirror finish to them. Let us know the name of the BAD CAPS you remove from your unit. You may even want to document with pics with a digital camera what you find. Well, good luck guy. 12fixlouie

Anonymous

  • 1138 Answers
  • Posted on May 23, 2010

SOURCE: monitor comes on for 2 seconds then goes blank

Check if the cable connecting your monitor from the video card is properly secure and not loose...
You can also try this... turn off your cpu..remove the cable from your video card.....Open the housing....remove your video card from your motherboard... clean the contact surface of the video card with moisten cloth.... after cleaning...connect the video card to the motherboard...attached the cable to your video card.. close the housing and try to boot again...

I hope that work.. if not my suggestion is you try your video card in other computer, try also the monitor to other computer.. to see which one failed.


Much appreciated if you rate this help.. thanks..

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I have Samsung syncmaster 733NW monitor. Dull display comes and goes sudennly when power ON.Blue light is glowing continuous. how to rectify

The issue you're describing with your Samsung SyncMaster 733NW monitor could be caused by a few different things. Some possible causes include a problem with the monitor's backlight or inverter, a malfunctioning video cable, or a software issue.
Here are a few steps you can try to troubleshoot the problem:
  1. Check the video cable: Make sure the video cable connecting the monitor to your computer is securely plugged in on both ends. If the cable is loose, the monitor's display may be affected.
  2. Check the power cable: Make sure the power cable is securely plugged into the monitor and the outlet. Try a different outlet or power cable to rule out any issues with the power supply.
  3. Check the monitor's settings: Make sure the monitor's brightness and contrast settings are set correctly. You may also try adjusting the resolution or refresh rate to see if that improves the display.
  4. Try a different monitor: If you have another monitor available, try connecting it to your computer to see if the problem is with the monitor or the computer.
  5. If none of the above steps resolve the issue, it may be a hardware issue. It could be a problem with the backlight or inverter, which would require repair by a professional. It could also be a problem with the monitor's main board.
If none of the above steps helps, it would be better to contact the manufacturer or a authorized service center to repair it.
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Dell backlight indicators

A computer monitor has a front-mounted LED that displays its current status and flashes in the event of an error. When an error occurs, the flashing may be accompanied by an error message on the screen. If the screen does not display an error message, the problem most likely falls into one of four common categories.

Unsupported Display Mode A video card has the ability to send output to the monitor at many display resolutions and refresh rates. However, no single monitor is capable of supporting every possible display mode. When the video card sends an unsupported display mode to the monitor, the monitor shuts off to prevent damage and blinks, or displays an error message. Standby Mode b> When a monitor detects no video signal from the computer, it assumes that you have turned the computer off and enters standby mode to reduce power consumption. Dell and HP monitors display an amber light when in standby mode. The status light on an Apple monitor blinks slowly. Incorrect Power Supply Some monitors such as certain Apple Cinema and Studio displays use external power adapters. Because different power adapters may have similar connectors, these monitors are designed to detect when an incorrect power supply is connected and blink the status LED rather than attempting to turn on. In the case of an Apple display, the LED blinks in an alternating short and long pattern. b> Backlight Failure b> A flat panel LCD display has an LED or fluorescent backlight that illuminates the pixels and makes it possible to see the contents of the screen. If the backlight fails and requires replacement, the monitor is unable to display any information. In some cases, you may be able to resolve this issue by turning the monitor and computer off, disconnecting and reseating all cables. If the monitor still has a backlight issue, it requires professional service.
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Tmy monitor shows the images only for 20 seconds, then it turns black.

Hi hope your monitor issue has resolved. I would suspect the problem is a hardware issue then a software setting. Since the monitor is over three and half years old, if your monitor is a LCD with CCFL back light and had been used almost every day, there may be 3 possible hardware issues. First is the internal power supply, that can go wrong due to heating problem within the monitor, this problem usually cause the monitor to display poor quality picture and may show interference lines on screen prior failure. Secondly, it may be the inverter that drives the back light, which may fail due to the safety circuit kicks in, because it involves with high voltages. Thirdly it may be the backlight itself, which is like most compact CCFL energy saving lamps that flickers or turn itself off when it reaches the end of its service life. This problem usually caused the monitor to show redness or yellowness images prior failure.

All of these can be resolved by qualified electronic repairers, all the best.

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Shows display for a second then it goes away

One guy suggested this from "computing.net":
Sounds like a driver issue possibly.
Start in safe mode and once in Windows, go to "Start", then "Control Panel", then "System". Next, click "Device manager". Then, find "Display Adapter". Right click and click "Uninstall". Reboot your PC and see if that helps. Post back if that doesnt help.

The problem could also be a slightly loose, or oxidized, backlight for the monitor. Read this blog about them, if the last suggestion didn't work:
http://answers.yahoo.com/question/index?qid=20080129223341AATk9OS
Good luck, and hope this helps.
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The inverter can be replaced easily but the CCLF lamp is more time consuming and requires soldering skills.
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Samsung monitor picture clicks off after 2-5 seconds...

Yes, It sounds like the backlight inverter circuit is shutting down. No inverter power, no backlight. On some monitors the inverter circuit will shot circuit the power power supply which makes the power light flash on some it just kills the backlight. You can usually check with a flashlight. Hold the flashlight pointed at the screen and see if you can see any of the icons or background picture. If you can then it is the backlight circuit or backlight tubes, usually the circuit.

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RE:monitor goes black

Monitor going black after a few seconds can be causd by a faulty power supply or inverter. Some monitors have both as one unit.
Sometimes it is basic failed capacitors, After that then I would look at transistors.
The average monitor from 17 to 20 and sometimes the 22s have usually 4 bulbs in them. One bad bulb will also cause the inverter to not fire up.
Bad bulbs usually show pinkish tint, or flickering or are dark at center top or bottom of the display.
ebays bammbammfran
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