White screen on my SyncMaster 2253LW

[AlainB]

Hi everybody. My first post here.

I found this forum while I was searching a solution for my problem with this monitor.

I have 2 of these monitors that I bought at the same time around 3 or 4 years ago. One of them I never had any problem with it. The other one I start to have problem with it about 2 years ago. In the summer, when it was very hot it started to flicker every 5 seconds or so. Just loose the image for maybe 1/4 of a second then get back Ok for another 5 or 10 seconds.

I installed a small computer fan near the ventilating opening and it solved the problem. Initially, I needed the fan only on hot days but eventually I needed the fan to be on all the time.

Until last week when I got more and more white screens. If I turn off and turn on the monitor, the image is good again for a short while before turning white again.

The problem is in the monitor, having swap with my other monitor and having test the bad one with another computer to confirm every thing.

The problem seem to be temperature related. The display will work well for first 10 minutes or so and using the fan will get me an extra maybe 5 minutes.

I don't find any obvious dammage to the circuit. But I can see that a portion of the board is getting hotter than the rest of the board. In the close up picture, you can see that the 2 front caps have suffered of a slight decoloration.

Any help to pinpoint the problem will be quite welcome.

Thanks!

Alain

[retiredcaps]

Re: White screen on my SyncMaster 2253LW

Can you post a picture of the main board?

Can you also post a picture of the panel or t-con board? This one will be near the top of lcd. Just follow the lvds cable from the main board.

[selldoor]

Re: White screen on my SyncMaster 2253LW

Are you willing to swap boards between the two monitors for test purposes.

That way it should be quick to establish which board needs further examination
( Board or lamps)

[AlainB]

Re: White screen on my SyncMaster 2253LW

There is just 2 boards on the display. Here is the other one. I don't have a great camera so this is the best I can do. There is no obvious dammage to this board too.

I forgot to mention that the defective display has at least 4 or 5 times the millage of the good one. Although they are both on 24 hours a day, each one on his own computer, the good one spend most of his time on black screen saver. When the defective monitor is working well the images are as clear and bright as the images on good one. One other thing is that the monitors are 5 years old, not 3 or 4.

For now, I must say that I am a bit reluctant to swap the boards with the good monitor. But I admit that it would be a great way to find where is the problem. I did not think about that!!

Thanks!

[selldoor]

Re: White screen on my SyncMaster 2253LW

Ok There should be another board at the other end of the flat ribbon cable with the blue stripe - that is the LVDS it may even just need that cable reseating.

Do you have a multimeter?

[AlainB]

Re: White screen on my SyncMaster 2253LW

Yes sorry, it was hidden under an aluminium foil. The connector seem to be glued. I will try to open it. Anything I should take care about?

On edit, no need to touch where the glue is just pressing sideways the small wire handles release the ribbon.

I saw on Youtube someone using an eraser to cleen the contacts. What do you think about that?

Yes, I have a multimeter.

[selldoor]

Re: White screen on my SyncMaster 2253LW

I saw on Youtube someone using an eraser to cleen the contacts. What do you think about that?

I often recommend that myself or Isopropyl alcohol

[AlainB]

Re: White screen on my SyncMaster 2253LW

The cleaning did not change anything. The white screen is now comming after only a few seconds. When the computer cable is unplug from the screen the "Check signal cable" window is visible on the screen.

[selldoor]

Re: White screen on my SyncMaster 2253LW

Is that clearly visible? does the on screen menu come on ok?


Retired caps will want a pic of that panelboard - as clear as possible- they
sometimes are marked with testpoints

[AlainB]

Re: White screen on my SyncMaster 2253LW

That is the only thing that appears on the screen. It is moving everywhere like if it was a screensaver.

[selldoor]

Re: White screen on my SyncMaster 2253LW

How long does that stay on. Then does it go black or white.
What happens if you then plug the pc in when the message is on
and are you using vga or dvi.

[AlainB]

Re: White screen on my SyncMaster 2253LW

If the cable is not attached to the monitor, the behaviour of the monitor is normal. The small window will appear and will stay on. The blue led will also stay on.

If the cable is attached to the monitor but not to the computer, the monitor will act as if the cable was attached to the computer when the computer is off. The blue led will blink and the display will be black. For that test, I used 3 differents cables that are working well with other displays. This behaviour is not the same with the good monitor. With the good monitor, the small window will appear if the cable is not attached to the computer or the monitor.

And at last, If the cable is attached to both the computer and the monitor, and the computer is on, the screen will be white.

All this using vga.

Here is the picture of the t-con board.

[selldoor]

Re: White screen on my SyncMaster 2253LW

Ok - Cant read anything it says on the panel board- perhaps a closeup of the two groups in the middle section.

On the back of the main board there is a label +5Vpanel
when it is connected up can you get at that to test?
If not it looks like there is a connection to a "Through" so you might be able to locate it on the other side of the board. Meter on v20DC black lead on a ground screw with the red lead probe the +5V or the "through" and see what voltage is on there.

The backlights appear to be good as you have white screen and the not connection message so problem is most likely to be on the main board or the panel board.

On the main board front there are at least two voltage regulators -there may be others- the two are bottom right corner one has 2.5 legs and the other has 3.

If you read this guide by retiredcaps it tells how to find test and post the results

https://www.badcaps.net/forum/showthread.php?p=261329

[AlainB]

Re: White screen on my SyncMaster 2253LW

On the connector that goes to the smaller board, I have the same voltage as the one written on the board. I also have other voltages on all the other pins except the green one. On that one, the voltage is 0.09 volts.

The second picture show what I beleive to be test points on the top long board. There is also 15 more points labeled TP129 and VR1 to VR14.

[rogfanther]

Re: White screen on my SyncMaster 2253LW

The tab in the big regulator in the logic board seems discolored. What is written in it, and what are the voltages in its legs ? With and without the cable connected.

[AlainB]

Re: White screen on my SyncMaster 2253LW

@selldoor

The 2 voltage regulators seem fine. I cannot find the datasheets but here it is

The lower one:

17-18
0829CG

pin 1: 0.00
pin 2: 1.79
pin 3: 3.65

The other one

8IL
17-33G

pin 1: 0.00
pin 2: 3.30
pin 3: 5.27

[selldoor]

Re: White screen on my SyncMaster 2253LW

Well they look ok - can you check the vga socket for bent or broken pins
do you have dvi cable you could try?

Try gently warming the mainboard with a hairdrier when it is all connect
-could be a dry joint.

Failing that one of the small on/off transistors could have packed up - perhaps another member can narrow it down.

[AlainB]

Re: White screen on my SyncMaster 2253LW

I am not trying to fix the monitor anymore. Even if I find the problem, it would be almost impossible to find the part needed. In a big city like Montreal it is already difficult to find a simple 105 degrees capacitor.

I just put back everything together and since it is still producing a nice white screen, it is not ready for the recycle bin yet. It will make a great artwork light table.

Thanks everybody!

Alain