Samsung SyncMaster 940N Flat panel Monitor - Answered Questions & Fixed issues

look for bad caps

Back - light problem. Check and replace damaged component/s at its back-light inverter board, or replace this board as card basis. If you wish to get some details; check the site linked here. Surf the site with patience. Pull up older posts. It will be best to replace the inverter board as card basis. http://electronicshelponline.blogspot.com/

940N?

This is a known symptom of a failure in the power supply board. Here is a link to a repair guide that shows how to dis-assemble and the unit and then what to look for and replace on the power supply board to bring the unit back to working condition.http://www.ccl-la.com/blog/index.php/repairing-a-samsung-940n-with-a-blinking-power-light/And here is a picture of the power supply board that needs to repair.I hope this helps, if so please rate my solution.BuddyMc

This is a known symptom of a failed power supply board. Here is a repair guide for this unit that shows how to dis-assemble the unit and then what to look for and replace to rebuilt the power supply board and bring the monitor back to life. http://www.ccl-la.com/blog/index.php/repairing-a-samsung-940n-with-a-blinking-power-light/And here is a picture of the power supply board.I hope this helps you, if so please rate my solution.BuddyMc

Your problem is usually caused by a bad power supply. You should be able to do the repair yourself, if just requires replacing 6 capacitors on the power supply board. Here is a link to a repair guide that shows how to disassemble the monitor and repair the power supply board.http://www.ccl-la.com/blog/index.php/repairing-a-samsung-940n-with-a-blinking-power-light/And here is the a picture of the power supply board.I hope this helps, if so please rate my solution.BuddyMc

This problem is usually caused by a failure of the power supply board controlling the back lights. Here is a link to a repair guide with disassembly and repair instructions that should help you get the monitor back up and running again.http://www.ccl-la.com/blog/index.php/repairing-a-samsung-940n-with-a-blinking-power-light/I hope this helps, if so please rate my solution.BuddyMc

Hello,

You need to have the 3 capacitors. There is not a 2460uf capacitor, If one of the 3 fail then the other two will still work, if you have just one capacitor and it fails then you have a dead power supply with the first failure.

Buddy
Corporate Computer
www.ccl-la.com

Most common failures in the LCD monitors are bad capacitors (bulging top/seal or leaking) in the power supply (they should be replaced in a set), blown fuses; poor solder joints, 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/albums/yy352/budm/ Post back what you see inside so we can guide you further and it will help out other people in the future also.

Basic LCD monitor and TV troubleshooting guide: http://www.fixya.com/support/r6150077-basic_lcd_monitors_troubleshooting http://www.fixya.com/support/r5093881-lcd_flat_panel_tv_troubleshooting_guide http://www.fixya.com/support/r7406380-tv_training_manuals Failed TV and Monitors pictures: http://s807.photobucket.com/albums/yy352/budm/

Learn about bad caps: http://en.wikipedia.org/wiki/Capacitor_plague

Capacitors kit: http://lcdalternatives.auctivacommerce.com/ he can make you a set of caps for you.Or www.digikey.com just make sure to use caps with low ESR, 105c, high ripple current, long life rating such as PANASONIC FM or FC series

Monitor this old will more likely to have bad DC filter caps by now, but you also may have failing LCD panel also. I would inspect the caps and voltages in the power supply section first.
You can failed SAMSUNG monitors due to bad caps in my albums.
You should read my guides also.
Basic LCD monitor and TV troubleshooting guide: http://www.fixya.com/support/r5093881-lcd_flat_panel_tv_troubleshooting_guide http://www.fixya.com/support/r6150077-basic_lcd_monitors_troubleshooting http://www.fixya.com/support/r7406380-tv_training_manuals Failed TV and Monitors: http://s807.photobucket.com/albums/yy352/budm Learn about bad caps: http://en.wikipedia.org/wiki/Capacitor_plague Parts: www.shopjimmy.com Capacitors kit: http://lcdalternatives.auctivacommerce.com/Default.aspx he can make you a set of caps. Or www.digikey.com, just make sure to use caps with low ESR, 105c, high ripple current and long life rating such as PANASONIC FM or FC series. Please post back what you find. Please leave rating if it helps.

If you are going to DIY and already try the monitor with another PC, and have proper tools and know safety precaution then please read on: Most common failures in the LCD monitors are bad capacitors (bulging top/seal or leaking) in the power supply (they should be replaced in a set), blown fuses; poor solder joints, 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/albums/yy352/budm/ Post back what you see inside so we can guide you further and it will help out other people in the future also.

Basic LCD monitor and TV troubleshooting guide: http://www.fixya.com/support/r6150077-basic_lcd_monitors_troubleshooting http://www.fixya.com/support/r5093881-lcd_flat_panel_tv_troubleshooting_guide http://www.fixya.com/support/r7406380-tv_training_manuals Failed TV and Monitors: http://s807.photobucket.com/albums/yy352/budm/

Learn about bad caps: http://en.wikipedia.org/wiki/Capacitor_plague

Capacitors kit: http://lcdalternatives.auctivacommerce.com/ he can make you a set of caps for you.Or www.digikey.com just make sure to use caps with low ESR, 105c, high ripple current, long life rating such as PANASONIC FM or FC series.

They can be 1000uf 25v (20% higher value is OK), higher voltage is also OK but it may not fit the board. The temperature rating must be 105c and Low ESR type which is very important for switching power supply. You should replace them in a set.
You can get the PANASONIC FM or FC series from DIGIKEY, or from Capacitors kit: http://lcdalternatives.auctivacommerce.com/ he can make you a set of caps for you.

http://www.fixya.com/support/r6150077-basic_lcd_monitors_troubleshooting Failed TV and Monitors: http://s807.photobucket.com/home/budm/allalbums

i have the same problem, also looking for an answer....

It depends bad the parts are broken, this is 2007 model, you may have hard time getting replacement parts, details pictures will help.
http://s807.photobucket.com/home/budm/allalbums

theo_christo, Get into my FIXYA profile and see if anything interests you or your BLACK or BLACK/BLANK screen symptom. Learn about the "flashlight" test that every "CCFL backlit lcd" monitor owner should know how to do and interpret the results of. 12fixlouie READ, READ, READ!

rcpips, You may need to replace one or possibly 5 -8 aluminum can "electrolytic filter capacitors" on the "switch-mode-power-supply/CCFL inverter board. If, as you say "works for 5 or 6 seconds" then that means that fuse is good. Another thing you will need to inspect SMPS board for is "cold" "frosty looking" solder joints where the components (surface mount or through hole) are soldered to the copper circuit traces. May need large magnifying glass or low power inspection microscope to locate them. Resolder any that look bad or loose. Some solder joints have thinner than "hair" thermal fractures that can also cause YOUR TYPE OF SYMPTOM!! PARTS: digikey. mouser. newark. and possibly Radio Shack. If buying filter capacitors, make sure they are rated 105 deg C only!! NOT 85 deg C!!! If caps need to be replaced (swollen, leaky) be sure to tell us the brand name you find installed on your unit! CAPXON, ELITE, JUN-FU are just 3 that you don"t want to find in your unit. BAD news if you do!! If DIY suits you, remember to document with "close-up" digital stills your unit tear-down, so you can reassemble unit without any "extra" parts laying on kitchen table!! Filter capacitors are polarized. You put them in + to +, - to -!!! if you put them in backwards they go BOOOOMMM!!! Hope this helps a little. lmistyrel on aim or 12fixlouie at fixya.

jcacolice, Most likely your 931c will need work done on it. When strange things start to occur with any LCD CCFL backlit display I would suspect the "switch-mode-power-supply" first thing!!! If unit is out of warranty you or someone will need to inspect and troubleshoot it. A good place to start will be to see some DIY videos on YOUTUBE. Try search of "lcd monitor disassembly" and "lcd monitor repair" and learn all you can about the TOP CAUSES of monitor failure. Then visit (FYI) www.ccl-la.com/badcaps.htm and www.badcaps.net for more info. Explore ALL your options before you do anything. Then get back to us here at fixya if you still need some asssistance. Read some of my other responses in my fixya profile and other those of other tech's on fixya.
Hope to see you back on fixya with a plan of action!! 12fixlouie

I have just had this same problem. The problem mostlikely is a blown fuse on the inverter board. Mine was blown on the board and also a Capacitor (470nF/25V) was bad beside the Fuse.

I replaced both and monitor is working now again. After install the picture was a little grainy with little artifacts. In another post i found that the Power Supply board needs to be cleaned for unwanted residue. After that picture was fine again.

BEWARE that you need a soldering iron and a steady hand to replace these parts. If you are unfamiliar with soldering at all have an expert take a look at this. The Power boards uses 220v so DO NOT connect it to the Power when opened.

Starworx

hello
I am a technician-informatic. I have repaired about 80 Lcd Samsung monitors with theese problems. I offer the repair manual.
Manual has been done with the experience of the repairing Samsung Lcd monitors. Manual was made by me and shows how to open monitor, how
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changing the main board) photo are included. 100% functional. The repair process is very simple 30-40min. (does not need a lot of
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"Not Optimum Mode 1280x1024 60Hz"
- The monitor turns on but turns off by itself, the LED blinks green.
- If you detach from the PC points to "control cable" the picture runs continuously in the vertical direction or presents while line , and
as soon as it is reconnected, the monitor goes off.
- The monitor does not turns on and dont dispaly anything, the LED blinks green-lit, if you detach from pc points to "control cable".
- The monitor turns on, works well some time, but after a window apiers "Not optimum mode. Mode recommended 1280X1024 60Hz"
- The monitor turns on, works well only with low resolution 800x600, when try to change a window that reads "Not optimum mode. Mode
recommended 1280X1024 60Hz"

the manual you can find on ebay (my ebay name is asnerejas123):
Samsung monitor repair manual guide 710n,913v,510n more
220498646211
Riparazione - repair Lcd Samsung monitor 710n,913v,510n
220498645860
Reparaturhandbuch für Samsung 710n,913v,510n und andere
220499443698

Hello

Sometimes you can get a good incation because the tops have domed over. However, the best method is to take each out of circuit and test with an ESR meter. Even though it's unlikely, other components can cause this same symptom. For more info see my website: www.micromendllc.com

Good Luck