Samsung 2033SW White screen (Distorted)

[Ch1p4@ll]

Help me Plzzzz....
I got a Samsung 2033SW the picture is ruin...
u can see the screen is white, but not totally...when i press the menu button the blue strip appear.... i checked the "F" at the panel its work fine,regulator also work at a precise voltage, no Bad Caps-leak (not tested with capacitor tester, i only have a multitester)

What i need to check next? plzzz help me..Thanks u very much

[momaka]

Re: Samsung 2033SW White screen (Distorted)

A white screen indicates a problem with the power supply circuit on the panel board (the one attached to the LCD panel).
Can you post more pictures of the panel board? Thanks.

[Ch1p4@ll]

Re: Samsung 2033SW White screen (Distorted)

A white screen indicates a problem with the power supply circuit on the panel board (the one attached to the LCD panel).
Can you post more pictures of the panel board? Thanks.

Thanks for the reply...
Here are the panel Pics.
Today i bought a Capacitor Tester n tested all the caps...all at Fit Condition.

n i tested all the "0" resistance...fine too...

Thank u very Much...

[Ch1p4@ll]

Re: Samsung 2033SW White screen (Distorted)

Nobody can help me???

[momaka]

Re: Samsung 2033SW White screen (Distorted)

Will post back with an answer shortly, need to examine circuit...

[momaka]

Re: Samsung 2033SW White screen (Distorted)

Okay, I'll need you to do the following measurements with your multimeter and post the results back:

1) measure the voltage labeled AVDD on the panel board. Use any of the nearby screws as a ground. I think it should be in the range of 10-15v.
2) with the monitor turned off and unplugged, measure resistance between AVDD and ground.
3) with the monitor turned off and unplugged, check diode SD1 either with diode test or by measuring resistance (use 2000 ohm scale if your multimeter is digital and not auto-ranging).

Also, what is the part number written on IC4? IC5 and IC11?
Last but not least, can you post slightly larger versions of the last two pictures in your post above? 1280x960 or larger would be great. Sorry to be so picky, but it's a bit hard to read the silkscreen on the PCB, which in turn makes it hard for me to give you test points.

[retiredcaps]

Re: Samsung 2033SW White screen (Distorted)

1280x960 or larger would be great.

2000x2000 is the max allowed here. I agree that higher resolution pictures would help alot.

[Ch1p4@ll]

Re: Samsung 2033SW White screen (Distorted)

Okay, I'll need you to do the following measurements with your multimeter and post the results back:

1) measure the voltage labeled AVDD on the panel board. Use any of the nearby screws as a ground. I think it should be in the range of 10-15v.
2) with the monitor turned off and unplugged, measure resistance between AVDD and ground.
3) with the monitor turned off and unplugged, check diode SD1 either with diode test or by measuring resistance (use 2000 ohm scale if your multimeter is digital and not auto-ranging).

Also, what is the part number written on IC4? IC5 and IC11?
Last but not least, can you post slightly larger versions of the last two pictures in your post above? 1280x960 or larger would be great. Sorry to be so picky, but it's a bit hard to read the silkscreen on the PCB, which in turn makes it hard for me to give you test points.

Thanks u

1) 4,73V
2) 1,117 ohm
3) 1,118 (- Side) & 1,189 -1,351 ohm (+ side)

IC4 =
AMW
J EZ

IC5 =
AGZ
E HL

IC11 =
78229
A61686 (or AG1G8G)
PHL 903

I will try to get a high res pic... matter is my internet conn is slow (30kbps)
i try my best....

Thanks for every reply

[momaka]

Re: Samsung 2033SW White screen (Distorted)

Well unfortunately, I can't find datasheets for IC 4, 5, and 11, but that's okay.

1) 4,73V
2) 1,117 ohm
3) 1,118 (- Side) & 1,189 -1,351 ohm (+ side)

Good progress.
Just so we are clear, though - for measurements 2) and 3), is the comma (",") between the numbers a decimal point? I'm asking because I know that in some (perhaps all?) European countries, a comma in a number indicates a decimal point.

If it's not a decimal point, then that means the main boosted voltage rail (AVDD) is not shorted and diode SD1 is fine. Since measurement 1) is low, the problem is most likely a shorted ceramic capacitor or diode in the positive/negative charge pump circuit (I outlined it in red, see attached picture below). If you can take a higher-quality picture or two of that area, that would be great and I may be able to point out which caps/diodes exactly need to be checked.

[Ch1p4@ll]

Re: Samsung 2033SW White screen (Distorted)

Thanks for the reply....
here is the pic....

[momaka]

Re: Samsung 2033SW White screen (Distorted)

Nice, good quality.

With your multimeter, measure resistance across the following ceramic capacitors (use 2000 Ohm scale):
CA60, CB44,
CA62, CA61, CA5,
CA7, CC2, CC3,
CD4, CD2, CD3, CA11, CA12, CA38,
CA2, CA58, CA57,
CA4, CA59
For each ceramic capacitor, make two measurements - have the probes one way for the first measurement and then reverse the probes for the second measurement. Basically, we need to check if any of those ceramic caps are shorted. Post the results for each capacitor here.
If you're having trouble finding where these ceramic capacitors are, locate D6 first. CA60 is to the right of D6. From there, follow the silk-screened marks on the board and you should be able to locate the rest of the ceramic capacitors.

You also need to check all of the diode packs in that circuit (again, using 2000 ohm scale). That is, check D6, D1, D2, D7, D8, and D5. Each of these diode-packs contain 2 diodes inside. I believe this is their datasheet sheet:

If you're unsure how to check these, see the image I attached below. Basically, if you put the (+) probe on pin 1 and (-) on pin 2, you should get a reading. Reversing the probes [ideally] should not give a reading. Then, if you put the (+) probe on pin 2 and (-) on pin 3, you should get a reading. Again, reversing the probes should not show any reading on the multimeter. Also, putting (+) probe on pin 1 and (-) on pin 3 should give a reading twice that of between pins 1 and 2. Reversing the probe should not give a reading, or if it does, it should be fairly high (at least 200 Ohms). Let me know if you get any weird readings and for which diode.

I know this might seem like a lot of work, but it should be fairly straightforward. If you're unsure about something, let me know.

[madhavs]

Re: Samsung 2033SW White screen (Distorted)

Guys, I'm not tech so don't follow the discussion going on... I too have a similar problem, but unsure if this is the root cause.

I have the Samsung 2033sw monitor and since last Sunday the monitor turns white after about 4-5 hrs of usage. Nothing happens when I press the menu button or switch off and on, simply stays white.

Then I need to disconnect the video cable, remove the power cable and reconnect only the power cable. It again starts with the white screen, but after about 20-30 mins everything comes back to normal and I can see the menu, the no signal message also is displayed. I connect the video cable and everything is back to normal.

The problem recurs again if the monitor is used for over 4 -5 hrs continuously.

Someone can tell me what I should do...

[PlainBill]

Re: Samsung 2033SW White screen (Distorted)

Guys, I'm not tech so don't follow the discussion going on... I too have a similar problem, but unsure if this is the root cause.

I have the Samsung 2033sw monitor and since last Sunday the monitor turns white after about 4-5 hrs of usage. Nothing happens when I press the menu button or switch off and on, simply stays white.

Then I need to disconnect the video cable, remove the power cable and reconnect only the power cable. It again starts with the white screen, but after about 20-30 mins everything comes back to normal and I can see the menu, the no signal message also is displayed. I connect the video cable and everything is back to normal.

The problem recurs again if the monitor is used for over 4 -5 hrs continuously.

Someone can tell me what I should do...

Those are a strange set of symptoms. Failing after 4-5 hours sounds like something is overheating. Ordinarily a white screen indicates a problem with the LCD panel itself. The fact that it fails to respond to the power button indicates it is a problem on the signal card.

The initial white screen after powering up is harder to explain.

First, I'd suggest a couple of tests. Note that when a monitor is connected to AC power a large part of the circuitry is on, even if the power button was used to turn it off.

1. Leave the monitor unplugged (no AC power) for at least an hour (overnight would be better) so it has plenty of time to cool down. Plug it in to AC power only (not hooked to a computer). What happens - does it power up with a white screen, or does it behave normally?

2. After using the monitor for several hours (but less than the usual time at which it will fail), unplug it, wait 15 minutes, plug it in and continue using it. How long until it fails?

3. Repeat test 2, but instead of unplugging it, simply turn it off via the front power button, then turning it on via the front power button.

4. Open the monitor up and take pictures of the power supply and the signal board. Attach them using 'Manage Attachments' - below the text entry area. Note the links in my signature.

PlainBill

[madhavs]

Re: Samsung 2033SW White screen (Distorted)

PlainBill,

Thanks for the inputs....

I left my monitor disconnected from the CPU and the mains for over 24 hrs and since then it has been working fine. No white screen / abnormal behavior even after 4 - 5 hrs of continuous usage.

I'm going to observe for a few more days and see if it acts up again and then will the steps you've mentioned.

Once again thanks for your support!