Dell E2311H: backlight always stays on

[Slyken]

Hello,

I'm trying to repair a weird issue with a Dell E2311H; the screen itself works perfectly, on both the VGA and DVI inputs.
But when the screen goes in power-save mode (orange LED) or when I press the power button, the screen goes completely white with the backlight to the maximum.

I tried to replace two capacitors (100uF 16V) on the control board, more for the peace of mind.
The only time the backlight was off with the power cable plugged was when I unplugged the cable between the control board and the power board, but maybe it switched to some sort of fault mode?

I attached two pictures:

• the control board, the top connector is for the video, on the top left the power (the one I disconnected), on the bottom left the screen buttons
• the power board, the power cable for the control board is on the right, the small green PCB connects to the backlight

I don't see anything strange on them and can't be sure which one is faulty.

[stj]

Re: Dell E2311H: backlight always stays on

it's probably a shorted transistor on the power board, i had a monitor that did that once.

[Slyken]

Re: Dell E2311H: backlight always stays on

Thanks for your answer; I found only two transistors: one in the middle with the heat sink and on the green PCB, both seem to be working (couldn't find a short).
But I checked every capacitor on this green PCB; C7 on the bottom-right measures only 100ohms, does it mean it's dead? I can't find anything on the INL859RN, the black IC that it's connected to.

[stj]

Re: Dell E2311H: backlight always stays on

well that's the led driver board,
what is the part number on that chip "u1" ?
if i can find a datasheet we can trace the pin that turns it on

[Slyken]

Re: Dell E2311H: backlight always stays on

I wrote its reference on my previous message; it's a INL859RN, but I can't find anything on it.

I checked for burned transistors on the video control board, all seem ok.
There is something I thought about: even if I fix the backlight, what could tell me this control board will not continue to produce a white image, even if I won't be able to see it?