30" Dell Ultrasharp U3011T troubles

[eriksalo]

Hi All; I have a huge Dell high resolution monitor that is having issues. The unit flickers and has wide horizontal lines on the screen. Here are some pictures:

#1 Desktop picture
#2 Full Red
#3 Full Green
#4 Full Blue
#5 Full White (it flickers, looks better in the picture than in real life)

What do you think?

[selldoor]

Re: 30" Dell Ultrasharp troubles

I think you will need to take the back off

[eriksalo]

Re: 30" Dell Ultrasharp troubles

I think you will need to take the back off

I took the unit apart and re-seated all of the connectors and ribbon cables. No change. I sprayed freeze on around the edges. No change. I cooled the whole monitor down to well below freezing (it's cold outside here in Colorado). No change.

All of the caps look good (no leaks or bulges).

I will replace the large power supply caps though I don't think that's the problem.

Any thoughts if I should replace all of the de-coupling caps on the main board?

[selldoor]

Re: 30" Dell Ultrasharp troubles

Please advise the model number and pictures of the boards would not go amiss. Is this the Dell model with the multiwire cable between , cant remember if this is the one with a tcon or direct from the main to the panel, but the insulation just rots away with the heat and shorts out.
If its not that , it looks like a bad tcon or faulty panel - some of these 30 inch dells have poor bonding strips - try pressing around the edges (gently) and see if the picture changes.

[Lumberjack777]

Re: 30" Dell Ultrasharp troubles

Good advice Selldoor, maybe he'll get lucky and it's just that cable.

If it's a Dell 3008 then it has a T-Con board. The first picture actually looks like T-Con problems with the blockiness and lines. BUT..... if it's cycling colors that's another issue. The pictures don't show "Full Red" "Full Green" like your description mentions. If that's the case (cycling solid colors) it's going into "burn-in mode". And you probably have an earlier revision of the main board. You need to replace some bad caps on the main board in that instance, before you end up with EEPROM corruption. Here's a thread dealing with that. https://www.badcaps.net/forum/showth...669#post372669

In post #2 I give the only 2 known methods to bring it out of Burn-in mode (color cycling)
Basically, you want to turn it on as little as possible until you can get inside and check those caps on the main board. Otherwise it can get stuck and you'll have to buy a main board.

[selldoor]

Re: 30" Dell Ultrasharp troubles

Hi L777 - Possibly multiple problem here is a tab bond thread
https://www.badcaps.net/forum/showth...=tab+bond+dell

[eriksalo]

Re: 30" Dell Ultrasharp troubles

Thanks for the great replies.

I generated "red" "green" and "blue" myself to see how it looked. The monitor appears to be trying to display correctly. It's not stuck in a test mode. From a desktop image, I can read the menu's and see the background.

As for the boards, there is a separate T-Con board. Part numbers are:

Monitor: U3011t
Main Board: L9164-10 (48.7F901.010)
T-CON: LM300WQ5-SLA1-611 (P/N: 6870C-0334A)
Power Supply: PS-2201-3-HF (Liteon)

[eriksalo]

Re: 30" Dell Ultrasharp troubles

Squeezing the edges or pressing the LCD screen around the edges has no effect on the image.

[Lumberjack777]

Re: 30" Dell Ultrasharp troubles

Oh I see now. It's a Dell U3011t. That's probably why most guys prefer the model in the thread title. Also for later searches from people with the same problem. But that's ok.

I have never worked on a Dell U3011t; but from my experience, when it's a T-Con problem the picture is stable. But you have blockiness, and lines. But the picture remains stable.

When it was a main board you'd often have color shifting, fuzziness, and instability of the picture.

I would check the voltage regulators on the main board. Retiredcaps has an excellent guide on how to check those. I can't seem to locate that thread. You can find it with some searching. Or maybe somebody else has that link.
Here's a youtube that also explains it. http://www.youtube.com/watch?v=cNFzBJELFoU

[Topcat]

Re: 30" Dell Ultrasharp troubles

If you cant fix it, hit me up, I have one with a broken screen that I could sure use a panel for!!

[eriksalo]

Re: 30" Dell Ultrasharp troubles

http://www.youtube.com/watch?v=cNFzBJELFoU[/url]

Thanks for your suggestion. I will go over the power supply with an oscilloscope tomorrow. All the caps looked good cosmetically.

I'm not clear exactly what "stable" means so I posted a short video on youtube showing the screen. Hopefully this will help illustrat the failure mode.

http://youtu.be/8TD3nOsK1eo

Erik

[selldoor]

Re: 30" Dell Ultrasharp troubles

This is the VR test thread L777 refers to
https://www.badcaps.net/forum/showthread.php?t=22231

[Davi.p]

Re: 30" Dell Ultrasharp troubles

I have marked with yellow what seems to be inductors for buck regulators, can you test both contacts in Volt DC? I'm not sure about the 2... Those marked in red seems to be linear regulators, search its datasheets and see which is the output pin then test it in Vdc.

[eriksalo]

Re: 30" Dell Ultrasharp troubles

Davi, thanks for looking at this. The voltages are:

Inductors (yellow), all numbers in Volts DC

1) Starts at 12V at power on but bleeds to zero volts (both pins) in about 30 seconds.
2) Appears to be a micro speaker (AC-1003N-RPB-LF), not an inductor
3) 17.19, 17.8
4) 1.28, 1,28
5) 3.34, 3.33
6) 3.32, 3.34

Regulators (Red), all numbers in Volts DC

1) GX1084-18 (This is a 1.8V 5A Linear Reg)

Pin1(Gnd): 0V, Pin2(Vout): 1.80V, Pin3(Vin): 3.28

2) 17-33 (This is a regulator)

Pin1(Gnd): 0, Pin2(Vout): 1.79, Pin3(Vin): 5.1

There is an additional regulator between Inductors #3 and #4. Measurements for that unit are:

3) GX1084-18 (This is a 1.8V 5A Linear Reg)

Pin1(Gnd): 0, Pin2(Vout): 1.79, Pin3(Vin): 3.31

Thanks for looking!

[Davi.p]

Re: 30" Dell Ultrasharp troubles

In fact i don't know which voltage is expected to be i have never repaired a monster like that, i was only searching for fluctuant or absent voltages but it seem not the case. That 17-33 regulator seems a fixed 3,3v output but exits only 1,8v, the marking is only 17-33?
The switching regulators: the 1 remains always 0v apart at the begin? It's strange the meaning of a smps dc reg that work only 30 secs, for the others it might be studied what's the normal voltage but without to be there is dificult. At the address http://www.beyondinfinite.com/library.html i can download a similar panel model datasheet, the inductor 3 seem obviously for the panel VCC (supply) 18v, there are no other supply tensions.

[tom66]

Re: 30" Dell Ultrasharp troubles

Try to locate positive and negative gate drive voltages. On T-con board. They are usually labelled VGH and VGL. Typically +25V and -10V respectively. Low VGL could cause this. I had an LCD TV with unstable image and horizontal lines - the VGL voltage was measuring 0V.

[Davi.p]

Re: 30" Dell Ultrasharp troubles

This is an example from another TCON, if VGL is bad check those component
around D105 diode. Bye.

[Lumberjack777]

Re: 30" Dell Ultrasharp troubles

Try to locate positive and negative gate drive voltages. On T-con board. They are usually labelled VGH and VGL. Typically +25V and -10V respectively. Low VGL could cause this. I had an LCD TV with unstable image and horizontal lines - the VGL voltage was measuring 0V.

That's interesting. I'm going to file that in my personal memory bank

That video really helped a lot Erik! Your voltages on your main board looked correct. I'm starting to think this might be T-con also. The blockiness; the lines. Hopefully you can track down the abnormal voltages and fix it. Your T-con board is also readily available for about 52 bucks all over and eBay.

Sorry The Boss! I think this looks repairable. Hopefully you can get a deal on eBay too <-- 3 Stooges icon

[eriksalo]

Re: 30" Dell Ultrasharp troubles

Try to locate positive and negative gate drive voltages. On T-con board. They are usually labelled VGH and VGL. Typically +25V and -10V respectively. Low VGL could cause this. I had an LCD TV with unstable image and horizontal lines - the VGL voltage was measuring 0V.

This is a great idea. I measured VGH and VGL on the T-Con board. Sadly, the voltages looked good and were solid as a rock on the scope:

VGH: +23.89 VDC
VGL: -10.5 VDC

Think I should try a new T-Con anyway?

[Davi.p]

Re: 30" Dell Ultrasharp troubles

Post at least an hires image of tcon, we can find those points to test others voltages, i cannot find it in the web, you can buy it at:
http://www.lcd-chip.com/ViewDetails12873.aspx