HP ZR2740w briefly show an image then turns off

[Gadgetfun]

Hi All,

I have issues with one of my two ZR2740w monitors. When I turn my monitor on the blue led turn on and after a few seconds shows briefly my desktop then turn off. I have made an slo-mo iphone video to demostrate my issue. Fastforward to 1.38.

I've searched the forum and found 4 threads about the ZR2740w but not a clear anwser.

Is this t-con issue?

Demo Video

Cheers!

[budm]

Re: HP ZR2740w briefly show an image then turns off

How about showing the pictures of the boards so we can see what we are dealing with?

[Gadgetfun]

Re: HP ZR2740w briefly show an image then turns off

Hi Budm,

Here are the images.

[budm]

Re: HP ZR2740w briefly show an image then turns off

So I look at the Video, the backligts came on for second and then went out?

[budm]

Re: HP ZR2740w briefly show an image then turns off

https://www.badcaps.net/forum/showth...hlight=ZR2740w

So what do you get on my post 3?

My Post 19:
You can put DC amp meter in series with each strip of the LED string to see which one is not drawing the current before it goes into shutdown mode. The circuit will shutdown if it detects short or open circuit in any one of the string. Most common failure in LED backlights is due to open LED.

I really like the post 20 remark to my suggestion:
'good luck with that theory,
i'll post some foto's of a strip, and driver board soon.
What he shown is not even the same what we were working on.

[Gadgetfun]

Re: HP ZR2740w briefly show an image then turns off

So I need to stripdown the whole screen till I see the leds right?

[budm]

Re: HP ZR2740w briefly show an image then turns off

You should take Voltage measurement for each LED string first just to see what you are getting.
Taking the LCD panel is the last thing you want to do, it is easily damaged.

[Gadgetfun]

Re: HP ZR2740w briefly show an image then turns off

I have dissemble everything and connected all together on the table. What happens is that there are two rows of leds at the bottom one left and one right. The Right one is not working. As you can see from the video is that for a short amount of time a image is displayed this is only from one row of leds.

[Gadgetfun]

Re: HP ZR2740w briefly show an image then turns off

See video demonstrating this.

Demo Video Leds

[Gadgetfun]

Re: HP ZR2740w briefly show an image then turns off

Aha lose connector.

[Gadgetfun]

Re: HP ZR2740w briefly show an image then turns off

I also see that one led is broken a piece chipped off.

[budm]

Re: HP ZR2740w briefly show an image then turns off

So you will have to check and see if that dead LED strip has one or more LED with open circuit or bad connection, the LEDs on the strip are connected in series so if one goes open circuit then whole strip will not light up.
Updated: you already found the cause of the problem.

[Gadgetfun]

Re: HP ZR2740w briefly show an image then turns off

So you will have to check and see if that dead LED strip has one or more LED with open circuit or bad connection, the LEDs on the strip are connected in series so if one goes open circuit then whole strip will not light up.
Updated: you already found the cause of the problem.

Now I hope I soldered it correctly :P and the chipped led is hopefully working.

Are those led strips for sale?

[Gadgetfun]

Re: HP ZR2740w briefly show an image then turns off

Woot!

[budm]

Re: HP ZR2740w briefly show an image then turns off

Nice, I cannot see how that SMD connector came off the board like that.

[Gadgetfun]

Re: HP ZR2740w briefly show an image then turns off

Are those led strips available to buy? It works but some leds are damaged.

[unilogic]

Re: HP ZR2740w briefly show an image then turns off

Hi Gadgetfun,
I completely disassembled the LCD (delicate and complicated!)
Have you ever found a replacement led strip? I've got two shorted leds on the left strip.

[Mario]

Re: HP ZR2740w briefly show an image then turns off

Hi Gadgetfun,
I completely disassembled the LCD (delicate and complicated!)
Have you ever found a replacement led strip? I've got two shorted leds on the left strip.

If you have access to old iMacs. 27" it's basically the same lcd. 2009-2011 . There probably are a bunch with dead GPU floating around.