Dell XPS 15Z 2beeps

[hazardus]

Hello,

I've a Dell XPS 15z with two beeps and no screen issue. I tried a different RAM it didn't help.
I replaced the SLJ4P chip with a new one but didn't help. What should I check?

Thanks.

[nazrul145]

Re: Dell XPS 15Z 2beeps

2 beep means ram not detected, you should clean ram slot. also you can change different cpu and flash bios.

[dellxps15]

Re: Dell XPS 15Z 2beeps

when u power on do you have 1.5volt on ram power coil?

[hazardus]

Re: Dell XPS 15Z no backlight

I changed the FETs and I got the 1.5V. Now it's turning on just no backlight. I checked KBC and on Pin47(LCD_BAK) I've nothing. I checked Pin70(PANEL_BKEN) and I've 3.3V there. What could be the problem? Why I don't have anything on Pin47?

[dellxps15]

Re: Dell XPS 15Z 2beeps

lcd_bakc could be 0 because it is setup to the maximum brightness.

try other flat cable or lcd if u can as u have bk enable voltage.

[hazardus]

Re: Dell XPS 15Z 2beeps

I forgot to mention that I tried with another display and different cable but nothing.

Edit: Also If you have time to take a look at the Page 27 you can see that the backlight enable pin name is LCD_BAK that's why I thought there should be something.

[dellxps15]

Re: Dell XPS 15Z 2beeps

edit:

pin 36 lcd_bak is backlight enable
u15 voltage on pin 120?

PS: did u connect back the little board for lcd open close signal ?

[hazardus]

Re: Dell XPS 15Z 2beeps

I got another board plugged it in and it shows picture so I guess something is wrong with my motherboard. I'll check those pins but I believe U15 should show something on Pin47.

[dellxps15]

Re: Dell XPS 15Z 2beeps

compare u15 pin 120 voltage.

[hazardus]

Re: Dell XPS 15Z 2beeps

Yeah, you are right. On the working board I measured pin120 and it shows 0V and on the nonworking board I've 3.3V. Gosh.

[hazardus]

Re: Dell XPS 15Z 2beeps

Checked R260 shows 0.7K in circuit. I removed it but it's fine because out of the circuit it shows 10K. I never understood what does can pull down the resistance?

[hazardus]

Re: Dell XPS 15Z 2beeps

So I've 0V on pin120 on the working board. I removed R260 from the other board. Guess what? Still no backlight! That's not the right direction.

Edit: I need that 3.3V on LCD_BAK pin47 without it I won't have backlight.

[hazardus]

Re: Dell XPS 15Z 2beeps

It was the KBC. solved. Thank you!