Dell inspiron 15 7559 gaming laptop NO BACKLIGHT!

[dlshad96]

Hi guys
I have dell inspiron 7559 no backlite is there any fuse to check. I replaced new screen and lcd cable nothing changed. So I think its about the motherboard .
any1 cane help me to find the fuse place please.
Thank you in advance.

[emestee]

Re: Dell inspiron 15 gaming laptop NO BACKLIGHT!

Why are you assuming it's the fuse? And, let's say it's the fuse, why do you think it's a good idea to replace it?

[mayss]

Re: Dell inspiron 15 gaming laptop NO BACKLIGHT!

What is the marking of your motherboard? DAAM9AMB8D0 Rev D? Do you have a video on another HDMI connector?

Remove the mainboard to the table, connect the power supply and ram memory and make measurements on the EDP CN10 socket. Pin 10,11,12,30,31,37,38,39,40.

[lapfix]

Re: Dell inspiron 15 gaming laptop NO BACKLIGHT!

Boardview/Schematics post #4

https://www.badcaps.net/forum/showthread.php?t=73005

[n0rb1x]

Re: Dell inspiron 15 gaming laptop NO BACKLIGHT!

I know this is an old topic but maybe it will help someone in the future. I had the same problem as a colleague and it turned out that resistor R118 in the Brightness Power circuit was faulty. Instead of 120 Ohms it was 501. It is the resistor between Q7 and Q8. My motherboard is DAAM9AMB8D0 REV: D

[brother john]

Re: Dell inspiron 15 gaming laptop NO BACKLIGHT!

thanks

[Boardsurfer]

Re: Dell inspiron 15 gaming laptop NO BACKLIGHT!

There is a schematic and boardview file available on this forum and I'm assuming you're using that. +LED_BL is a reference to the pins on the connector that pass 19.5V to the LCD panel to be boosted and then drive the backlight. While the machine is on and you see a faint image on the screen measure the value of +LED_BL which should be 19.5V. If you have 19.5V at the connector and still no BL the panel or cable is probably defective. If you have nothing at all at +LED_BL then there is probably an issue with enable at component Q10 or other nearby components involved in enable. Q10, when working properly, should have 19.5V on PWR_SRC (pin1) and 3.2 on +LED_BL_ON (pin2) which should then open the gate and allow 19.5V to go to the the connector. If you have both those readings and still 0.0 at pin 3 then replace Q10. Keep in mind that a common cause of this board issue is an issue with the LCD cable or panel which causes shorting of +LED_BL and subsequent frying of Q10 or other components along +LED_BL.

There is no in-line fuse like on many other similar Dell machines.

Hope this helps.