Samsung 931C bad caps repaired.

[Wizard]

Yesterday replaced bad caps in my monitor as preventive measure.

They were capxon. One was bloated slightly for inverter supply, this checks ok on ESR meter even other caps except other one showed slightly higher ESR so I did re-capping just in case. This is 3 years old LCD just 2 weeks left on warranty.

Oh yeah, finally tore out the blue LEDs for orange LEDs for power LED. Much better look.

Cheers, Wizard

[otoluk]

Re: Samsung 931C bad caps repaired.

Repaired one too...

Symptoms: Doesn't turn on. After power is plugged-in backlight and power led flashes nonstop, again and again.

Board: Power board - UM1719-VE REV 0.2 2007.02.27

Fix: Replace unknown brand bad capacitors C110, C109, C111 and Sam Young caps C113,C316,C112

Maybe C114, C107 should be replaced too but I left as it is, they are small and tested good.

Shoplist or set for model 931C:
C110,C109 = 10V 1000uF
C111=10V 330uf
C113,C316,C112=25V 820uf

C114=1uf 50V
C107=47uF 50V

[guest931]

Re: Samsung 931C bad caps repaired.

Same problem, Samsung 931c 19" 2ms, 2000:1, 3-6 years old.
Hopefully I can get mine replaced too.
I was told to check Newark and Mouser for replacement caps.

http://www.youtube.com/watch?v=3GibgiK0cbA

I watched this video and it helped me to take my monitor apart, although its not the same one, and once i got the main frame apart, I disconnected 3 wires so I could flip the big metal part over, then i took out the 3 screws and flipped the board over and saw the capacitors.

My LCD would have to be turned on and off several times, before it finally would work. Each time i powered down and back on, it would take more time to get it going, so it was getting worse each time, but if I left it on, it was fine and would stay on, but if i switched resolutions or the power went out, back to the issue...finally today, after 1 hour of trying, I came here for help. I am very happy to see someone had the same LCD and same problem, but different capacitors.

[jetadm123]

Re: Samsung 931C bad caps repaired.

Same problem, Samsung 931c 19" 2ms, 2000:1, 3-6 years old.
Hopefully I can get mine replaced too.
I was told to check Newark and Mouser for replacement caps.

http://www.youtube.com/watch?v=3GibgiK0cbA

I watched this video and it helped me to take my monitor apart, although its not the same one, and once i got the main frame apart, I disconnected 3 wires so I could flip the big metal part over, then i took out the 3 screws and flipped the board over and saw the capacitors.

My LCD would have to be turned on and off several times, before it finally would work. Each time i powered down and back on, it would take more time to get it going, so it was getting worse each time, but if I left it on, it was fine and would stay on, but if i switched resolutions or the power went out, back to the issue...finally today, after 1 hour of trying, I came here for help. I am very happy to see someone had the same LCD and same problem, but different capacitors.

Suggest you replace all the electrolytic caps with the exception of the large 450V one. digikey.com would be a better choice for replacement caps as they have cheaper shipping for small orders. Many members will suggest you use Panasonic FM or FC series caps as replacements. Good Luck!

[otoluk]

Re: Samsung 931C bad caps repaired.

Why different capacitors, they all are bad even if they ar not bloated. Replace all of them I listed and it should work. When byu ask for good(not from China) capacitors and most expensive you can get. Just take the samples with you so to watch the dimensions of capacitors, as good caps are sometimes larger and not always fit.

[Slavixs]

Re: Samsung 931C bad caps repaired.

Sorry for placing up an old topic. But I too have the same problem, replaced all capacitors except that big one (450V)! But still I can't turn it on. Is here is other solution, or where I need to chek first? Thank You!

[budm]

Re: Samsung 931C bad caps repaired.

Sorry for placing up an old topic. But I too have the same problem, replaced all capacitors except that big one (450V)! But still I can't turn it on. Is here is other solution, or where I need to chek first? Thank You!

Please post GOOD and CLEAR pictures of the board so we will know which version of the board we are dealing with, make sure to use ATTACHMENT for uploading the pictures.

[Slavixs]

Re: Samsung 931C bad caps repaired.

Please post GOOD and CLEAR pictures of the board so we will know which version of the board we are dealing with, make sure to use ATTACHMENT for uploading the pictures.

Ok, here it is!

[retiredcaps]

Re: Samsung 931C bad caps repaired.

If you have a multimeter, check all the DC voltages on connector CN2. If it is working properly, you should see the voltages as per legend.

[Slavixs]

Re: Samsung 931C bad caps repaired.

ok, will try, thank You!

[selldoor]

Re: Samsung 931C bad caps repaired.

But I too have the same problem, replaced all capacitors except that big one (450V)! But still I can't turn it on.

Hi - can you say exactly what the problem is.
Doesnt do anything at all when switched on?
Flashes then goes off.?
Clicks/Buzzes/hums/?
Power light - colour? flashes/ comes on then goes off?


Have you checked the power cable. Does it work on another monitor.
Does it have a fuse in it?

If it doesnt come on at all and you have no voltages as per retired caps
test. Check the fuses on the board.
There is red barrel shaped fuse just behind the main power socket at F101
Please check this - Power OFF -set meter on resistance and put one probe on each side of the fuse contacts, on the back of the board - post the result - it should be the same as touching the probes together.

There is another fuse - a green torpedo one on the right hand side in your picture under the word DIP at F301 - test that as well.

You said you replaced ALL the caps is that correct , including the small one at C107 as this is probably the start up cap.

The picture of the top of the board is great but bottom could be better without flash? - The solder joints on the main supply socket pins look a bit ringed ,which may mean they need re soldering.

[selldoor]

Re: Samsung 931C bad caps repaired.

But I too have the same problem, replaced all capacitors except that big one (450V)! But still I can't turn it on.

Hi - can you say exactly what the problem is.
Doesnt do anything at all when switched on?
Flashes then goes off.?
Clicks/Buzzes/hums/?
Power light - colour? flashes/ comes on then goes off?


Have you checked the power cable. Does it work on another monitor.
Does it have a fuse in it?

If it doesnt come on at all and you have no voltages as per retired caps
test. Check the fuses on the board.
There is red barrel shaped fuse just behind the main poer socket at F101
Please check this - Power OFF -set meter on resistance and put one probe on each side of the fuse contacts, on the back of the board - post the result - it should be the same as touching the probes together.

There is another fuse - a green torpedo one on the right hand side in your picture under the word DIP at F301 - test that as well.

You said you replaced ALL the caps is that correct , including the small one at C107 as this is probably the start up cap.

The picture of the top of the board is great but bottom could be better without flash? - The solder joints on the main supply socket pins look a bit ringed ,which may mean they need re soldering.