Samsung SyncMaster 931B 19" LCD Monitor - Answered Questions & Fixed issues

Hello,

It sounds like you have a monitor with a common problem, we have repaired many Samsung monitors with this problem. After a few years some LCD monitors will blow a power supply. The problem is caused by parts called capacitors overheating in the confined space of the monitor. If you are good at electronics repair/soldering you can usually fix the problem. Check out a few pictures on my web site www.ccl-la.com/badcaps.htm You can take the back cover off your monitor and look for the bad parts,replace any that look like the pictures and your monitor should work fine. The capacitors do need to be installed with the correct + and - connections, note the stripe on the old one and insert the new one the same way. If you can't do the repair we offer a repair service, contact us for more details or if you have more questions.

I hope this helps, if so please rate my solution.

Buddy
Corporate Computer
www.ccl-la.com
Over 21 years of computer and printer support/repair

There has to be a setting in the menu for the monitor...I would look in the menu in the monitor settings on the monitor itself, and find a reset selection, to set it back..

check the power cord, set to the monitor correctly, if still dead, open the monitor, check the power supply module, find some capacitor inside it, if became puffed or leaked change with new one.

I tried the following options and neither worked. 1) Hitting the monitor buttons as stated only got me a "digital" message and then the monitor went black as usual. Never got to any menu options. 2) Going into Safe Mode and changing the monitor settings or downloading/installing the correct driver didn't stick once you went back to the normal startup.

I didn't have another monitor handy to swap out so I had to be a little more creative. The only solution that worked for me is re-booting (F8 during startup) into the mode "Enable VGA Mode". This allowed me to go into the normal desktop with a screen resolution of 800x600. I went online, found the driver, downloaded it to the desktop. Deleted the video driver (Device Manager), installed the downloaded version, rebooted and....no problems.

I have Windows XP. Hope that helps. :)

hi, these mosfets are obsolete now, do you know a good equivalent for them?Thanks

Did it happen all of a sudden? In other words, was it OK before?

Try going to screen preferences, settings, and look at the resolution slider - is it set to the native resolution of your monitor (1280x1024)? If not, correct and accept changes.

If the resolution is set OK, then multiple other things might have happened, but not knowing a bit more about the situation it's hard to advise anything...

press the menu button until for couple of seconds and this will disable the lock!

There is no risk of radiation through an LCD. Only blinding light that can give you a headache. (I tried using a CCFL as a desk lamp. Headache follows, and despite what people keep telling me, I don't think I look like was born at Chernobyl.) As for the scratch, you must first come to terms that your monitor will never again be perfect, and then decide what is the best course of action for yourself and your skills with the understanding that this will not be easy and it will take quite some time. Personally, this is what I would do. Use something to very carefully blot the bright spot, I would probably use a tiny bit of ink on the tip of a sharpened toothpick. (Apply at a bit of an angle parallel to the scratch to avoid pressure points and stray ink.) It is better to have small dark spot on the screen than a bright one. Next, turn off then unplug the monitor and lay it down as flat as possible. Then, with a very soft touch, clean the entire screen with a gentle sanitary wipe. No strong or abrasive cleaners. If t.p. is what you have than that is what you have. If the wipe is dry, put just enough water on it to make it just damp enough to clean the surface. Take a damp q-tip and dip it in some ash then brush off any rough particles. Gently rub the ashen q-tip along the scratch lengthwise using as little pressure as possible. Rubbing across the scratch may make things faster, but will make the blemish larger, trust me. Repeat with the ashen q-tip until you are satisfied that the edges of the scratch are no longer rough. Very carefully with a barely damp fresh wipe, remove the rubbing's from the screen. Here comes the hard part. What to use to help close the gap, and gloss the finish. Nothing that I have seen or tried is perfect. My fist choice would be to leave it and thank whoever you do or don't pray to that it still works. If this is not acceptable, then if possible, get or debo an anti-dust or anti-glare or privacy screen for the monitor. If this is not possible, but you have access to a water based clear acrylic pen with a satin finish, you could go with that. Do not use gloss or high gloss, shiny things attract attention. Whatever you use to cover the scratch, make sure it is water based, because the solvents in others will tarnish or melt the plastic overlay of the LCD. Another possibility is, if you know someone in the area who paints, perhaps you could get a little water based clear coat with a satin finish, and use a tiny bit of sponge to apply it to the screen. Using even a small brush will leave brush strokes, but if that is what you have, then that is what you have. Best of luck to you, I hope it works out. :)

It may have unstable DC voltages due to failing DC filter caps which is very common problem to all LCD monitors as shown in my albums.
If you are going to DIY 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 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.

Basic LCD monitor troubleshooting guide: http://www.fixya.com/support/r6150077-basic_lcd_monitors_troubleshooting

http://en.wikipedia.org/wiki/Capacitor_plague Capacitors kit: http://lcdalternatives.auctivacommerce.com/ he can make you a set of caps for you.

Hi

This is a problem with a high magnetic field hence you need to de-goz the screen. Or leave it un-used for some time and it will be alright by itself.

Maybe when you were shifting you have kept a speaker with big magnet around the monitor thats why this has happened.

Dont worry it will go bad to normal by itself.

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 monitors to get some ideas what to look for: http://s807.photobucket.com/albums/yy352/budm/SAMSUNG/ 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 Parts: www.shopjimmy.com Parts: http://interliquidparts.com/

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.

All the caps have completely flat tops?
http://s807.photobucket.com/albums/yy352/budm/SAMSUNG/Samsung%20943T/

Do you see the backlights try to flash on for a second at least?
You need to check the DC voltages of the 5vdc line and the 16~18vdc line for the inverter circuits using 12v bulb as a dummy load (do not hit the pwoer switch, make sure to turn it off, the power supplies are running the minute it is plug into the wall).
Please note that bad cap can look normal but can have high ESR.
Service manual (not sure it matches exactly to your chassis): http://elektrotanya.com/?q=showresult&megnev=SAMSUNG&megnev2=943b&kategoria=monitor&kat2=all
Please read my guide to get more understanding:

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.

i need a better picture picture, help

Looking like there is a failing capacitor in the power board. Or it may be a bad "dry" joint on the circuitboard. The fact that there is intermittent power, could also suggest that the connection at the 3 pin kettle plug in the monitor is loose or worn, although it is more likely that the fault lies internally. Before taking this to a qualified repairman / woman, try substituting the power lead with a known good one, just to eliminate the possibility of it being something as simple as that. I'd also check the connections from the graphics card on your PC to the monitor and it is also worthwhile testing the monitor on another computer or laptop.

Given these monitors problems, I'd suspect capacitors though and this will need to be checked by a professional

this problem can occur cause of two cases 1 problem with LCD panel (replacement can solve) 2 power failure in side moniter (repairing moniter can solve)
thanx PLZ vote

Click here for my solution.

You have a power supply problem and inverter board issue, this is caused by bad capacitors that sometime bulge at the top. The only way to fix this is replace the boards or attempt a repair on the boards. If repaired professionally the cost may not justify the expense, probably cheaper to replace.

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Sounds like some bad electrolytic capacitors, it's easily fixed. I highly recommend reading the links at the bottom, it'll give a you a better insight into the problem and solution.

You have 2 or 3 options:

1. If it's under warranty then you could send it back to be fixed, problem is they will likely use the same rubbish brand of capacitors again, but anything else will void the warranty.

2. Pay a tv repairman or similar to fix it for you. They may still use substandard capacitors, so specify what brand you want them to use, this will probably mean waiting longer and possibly paying a little more. This way you know the job should be done right.

3. You could replace them yourself if you're comfortable with a soldering iron, or know someone who is. The capacitors themselves are quite cheap and easy to replace.

Go for the best ones you can get for the job and try to buy from reputable companies, the links below will help you chose but you can't go wrong with Rubycons. Every capacitor manufacturer has several ranges, each having different properties which make some more suitable than others

Always match the values on the original capacitors. You can actually use slightly different values for the capacitance and voltage (uf and v) but never use ones below what the originals are rated at.

The links below will explain this further.

They should look something like this:

As you should be able to see, the one on the left is bulging. The blue stripe with the arrow tells you that the lead on that side is the negative, the positive lead should also be longer than the negative one(only on a new cap, old ones will have been trimmed).

Tools needed
-----------------
1. Soldering iron. - preferably with a stand with a sponge in.
2. Solder - there's different types so make sure it's suitable for electronics
3. Phillips screwdriver
4. Flat head screwdriver
5. Wirecutters
6. De-soldering wick, or pump. - definitely recommended but not really essential.

If you haven't already got the tools then it's a good investment, as bad caps cause a lot of faults in all kinds of electronics.

Instructions
--------------
1. Unplug monitor and open case.

2. Identify power board, it should have a lot of electrolytic caps on there and obviously should be connected to where the power lead is attached.

3. Identify the bad caps, they should be bulging and/or leaking, although not always. Note down the three values for each cap (eg 220uf, 16v, 105c) and their approximate dimensions, and get new ones, preferably Rubicon or Panasonic, the link below will help you chose some good ones. If in doubt you could remove them and take them to the shop, but you'll have to remember where each one goes and which way round it was (take pics).

4. Very carefully heat up the contact on one side with the soldering iron, and rock the cap the other way, then do the other side, keep doing this until the cap comes out, if you have a de-soldering wick/pump use it to remove the solder and it should just pop out easily.

4. Replace with new cap, making sure that you observe the polarity and make sure it's securely seated and soldered in. Make sure the solder is neat, tidy and doesn't contact anything else. If there's any solder left in the holes then you'll have to heat it up or remove it before you can get the new cap's leads through. Once done properly trim the leads off so they won't cause any problems.

5. Replace casing and test. If it doesn't work then you'll have been a bit messy with the solder, tidy it up and try it again.

Here's a few links to help you:

Bad caps faq - should have pretty much everything you need to know.
http://www.badcaps.net/forum/showthread.php?t=425

Hints on soldering.

http://www.kpsec.freeuk.com/solder.htm

only avail at samsung service

u can change electrolitic capacitors in the power board