Dell Inspiron 7520, LA-8241P mainboard problem, power on black screen

[dudochnicht]

Hi, i have a Problem with my Dell Inspiron 7520 LA-8241P Mainboard.
When i start it, all LED's turns on but the display is black.
Shortly after starting I noticed a click on the mainboard but don't know where it came from.
I have tested it with the i5 and after the click the laptop goes off but with the i7 the laptop stays on after the click .
The Dell Inspiron 7520 supports the i7

What I've already done:
- start without RAM and it beeps 2 times
- start without bios battery and it beeps 5 times
- Press D on start, but show nothing, the display remains black
- CPU changed (i5-3210M to i7-3632QM) -> no improvement
- flash new BIOS (original BIOS A10 from Dell) -> no improvement
- RAM changed -> no improvement
- Display changed -> no improvement
- the Battery is charging

I don't know what the problem is and my technical understanding is very limited.
Has someone ever had the same or a similar problem and have a solution?

[mcplslg123]

Re: Dell Inspiron 7520, LA-8241P mainboard problem, power on black screen

This mb has discrete ATI graphics chip and its known to fail. Try disabling the GPU and see if shows display on screen. The screen has to be connected, else it wont boot at all. You can disable GPU simply by removing graphics coil. After disabling GPU, try with i5 cpu as it may not support i7 on igpu.

[dudochnicht]

Re: Dell Inspiron 7520, LA-8241P mainboard problem, power on black screen

This mb has discrete ATI graphics chip and its known to fail. Try disabling the GPU and see if shows display on screen. The screen has to be connected, else it wont boot at all. You can disable GPU simply by removing graphics coil. After disabling GPU, try with i5 cpu as it may not support i7 on igpu.

Thanks for your Answer.

I removed the graphics coil and changed the i7 to i5 and switched on the laptop ... black screen :-(.

Nothing has changed, except for:
It switches off after 5 seconds, about 2 seconds after the click (with the i5).