Dell Inspiron 15R 5520 video issue

[p1muserfan]

Have an Inspiron 15R 5520 that has a dull white screen on boot up but when I plug in my external monitor the image is fine on the external. Have already tried a new video cable, no luck. Is it safe to assume the north bridge is o.k. because the image is fine on the external? I'm thinking something is up with LVDS circuit from connector (p. 22 of attached file). Or will I be attempting my first reflow?

[dspok]

Re: Dell Inspiron 15R 5520 video issue

@p1muserfan
did you try new LCD panel?

[p1muserfan]

Re: Dell Inspiron 15R 5520 video issue

Yep, same issue

[senchire]

Re: Dell Inspiron 15R 5520 video issue

I've 2 acer 5520 with the same problem. And (in my case) its 100% the NB (MCP67 from nvidia), I've reballed them but they are fragile new order should come to fix this.
Now I didn't worked on that one, but in case they share the same MCP67 chip there is a chance the NB is the case.

[abbas_govani]

Re: Dell Inspiron 15R 5520 video issue

hey guys m having same problem with dell 5520 and 3521. i had diagnose that the power on inverter power source is 19 v on ideal but when i power on the laptop voltage drops to 4 watt. does any one know how to solve this. i had check new lvds cable and led too. but the problem is same.

[keeney123]

Re: Dell Inspiron 15R 5520 video issue

Have an Inspiron 15R 5520 that has a dull white screen on boot up but when I plug in my external monitor the image is fine on the external. Have already tried a new video cable, no luck. Is it safe to assume the north bridge is o.k. because the image is fine on the external? I'm thinking something is up with LVDS circuit from connector (p. 22 of attached file). Or will I be attempting my first reflow?

Are you sure that the internal screen is turned on by the software? That would be some type on Fn + F5 combination? If it is turned on then I would go to on page 22 in the schematic where the LCD backlight and power is and look for the power there.

[samanthban]

Re: Dell Inspiron 15R 5520 video issue

check qv4 pin 1

[kiraro]

Re: Dell Inspiron 15R 5520 video issue

Check LCD_VDD signal it must be 3.3v if it is missing you will have a white screen on your LCD when laptop boot, few days ago i repaired a dell inspiron 5110 with the same problem and i found LCD_vdd missing it was a transistor switch faulty i replaced and No white screen and every thing OK.sorry for m'y bad english

[abbas_govani]

Re: Dell Inspiron 15R 5520 video issue

Are you sure that the internal screen is turned on by the software? That would be some type on Fn + F5 combination? If it is turned on then I would go to on page 22 in the schematic where the LCD backlight and power is and look for the power there.

there is picture on screen but it is dull (no backlit). inverter prower drops when I attach new led and also changed cable too.

I will check check qv4 pin 1. as told by samanthban

[abbas_govani]

Re: Dell Inspiron 15R 5520 video issue

thanks all guys for your help. there was problem in qv6. si3457 .
I changed that mosfet and now it works fine.

[keeney123]

Re: Dell Inspiron 15R 5520 video issue

Good for you for locating the problem glad you got it working.