inspiron 15r no backlight but voltages seem OK

[frosty3907]

Can see screen with flashlight only.
Dismantled and checked voltages on LCD controller board:

LED_EN 3V
V_OUT 0V
V_LED 19.3V
PWM 2.85V
YVCC 2.43V
LB1~8 0V

no voltage at any of the pins on the ribbon connector going to the LEDs.

This is a quite new laptop.

[frosty3907]

Re: inspiron 15r no backlight but voltages seem OK

Here's another photo but my eyes can't quite make out the chip number.

The LCD panel model is B156HW02 V1, h/w: 4a by au optronics
D/pn 035k06

Link to datasheet here but I can't download, needs registration.
http://www.panelook.com/B156HW02%20V...meter_688.html

[frosty3907]

Re: inspiron 15r no backlight but voltages seem OK

I tested F401 shown in image and there was no continuity, is it meant to be a fuse??

I'll await someone's confirmation since last time I jumped the gun.

[trebo]

Re: inspiron 15r no backlight but voltages seem OK

I tested F401 shown in image and there was no continuity, is it meant to be a fuse??

I'll await someone's confirmation since last time I jumped the gun.

F401 is a fuse

[frosty3907]

Re: inspiron 15r no backlight but voltages seem OK

I shall replace

[frosty3907]

Re: inspiron 15r no backlight but voltages seem OK

Replaced fuse and protection ic went up in smoke.

Whole panel is cactus now I guess?

[Th3_uN1Qu3]

Re: inspiron 15r no backlight but voltages seem OK

I have two of that model panel in different states of broken-ness. It seems to be a common issue with them. Unfortunately, there is no way it can be fixed, short of swapping the chips from an identical screen with another issue (like smashed).

[dspok]

Re: inspiron 15r no backlight but voltages seem OK

I guess there is some bad caps which are short.

[frosty3907]

Re: inspiron 15r no backlight but voltages seem OK

Even if I replaced the protection ic it would just blow again. Seems these panels might have an issue based on the number of 15r n5010 threads. Super annoyed

[frosty3907]

Re: inspiron 15r no backlight but voltages seem OK

What if I bridge the v_out and v_led test points? Try and cram 19v directly into the LEDs? Or is there a better way to do that?

[frosty3907]

Re: inspiron 15r no backlight but voltages seem OK

Although I guess that probably will use too much power because it won't be pulsing?
I don't know seems a shame to throw out a perfectly functioning HD LCD panel.

[frosty3907]

Re: inspiron 15r no backlight but voltages seem OK

You'll never believe it but I got the backlight working by bridging the two test points mentioned above, connecting ground to the LCD ribbon shield and removing two LEDs from each bank of 9. It flickers a bit and uniformity isn't great but there's a problem with the LCD panel!!! >

It is divided into three distinct horizontal sections, the middle section looks right, the left section darker than usual and the right section brighter, it's not the backlight because the change is too sudden. What the heck is that about??