ASUS K50IJ with lp156wh2 no backlight in led

[nalle077]

Hello. My friend gave his broken laptop to me and now I want to fix it.
It is an ASUS K50IJ and the led is LG lp156wh2 There is no backligt when starting the laptop but I see picture when using a flashlight. I have taken out the led and I saw a kind of burned connector. I have cleaned the cable and connector and it looks really good, but still no picture. I have measured 2 fuses on the ledboard and the were ok. The question is, why the burned connector, what is the problem now and if I buy a replecement led (about 60$) will that fix the problem or can it be a problem on the motherboard??
Best regards Nalle077

[lord]

Re: ASUS K50IJ with lp156wh2 no backlight in led

First check if you have sufficient voltage on that connector. Also you can connect the LED backlight to a external power supply and check them.

[nalle077]

Re: ASUS K50IJ with lp156wh2 no backlight in led

First check if you have sufficient voltage on that connector. Also you can connect the LED backlight to a external power supply and check them.

Thanks for the reply. I have no electrical scheme for the led, so I do not know what the voltage should be. I have looked but can not find a scheme for that led. Help Please

[nalle077]

Re: ASUS K50IJ with lp156wh2 no backlight in led

Thanks for the reply. I have no electrical scheme for the led, so I do not know what the voltage should be. I have looked but can not find a scheme for that led. Help Please

I have found a schematic for the led but it only shows the 40 pin connector.
I have measured number 38-40 with output about 10,7V and number 36 with about 3,8V. seems ok I think. I think the problem is the little connector that I wrote about earlier. the one in the corner of the picture. I have no schematic about that connector. I measured just to see there were any power there, and got 10,7V on one of the "pins" it is hard to say if anything is "in the wire" because it has plastic over it. But that was my thought if it has bad connection after it got "burned" even if I have cleaned everything.

[nalle077]

Re: ASUS K50IJ with lp156wh2 no backlight in led

I have found a schematic for the led but it only shows the 40 pin connector.
I have measured number 38-40 with output about 10,7V and number 36 with about 3,8V. seems ok I think. I think the problem is the little connector that I wrote about earlier. the one in the corner of the picture. I have no schematic about that connector. I measured just to see there were any power there, and got 10,7V on one of the "pins" it is hard to say if anything is "in the wire" because it has plastic over it. But that was my thought if it has bad connection after it got "burned" even if I have cleaned everything.

Anyone who can help me ?

[rtstorm]

Re: ASUS K50IJ with lp156wh2 no backlight in led

on the LCD board you have GND, put black probe on that and red probe on that burned connector pin. (laptop must be turned on ofc ) post the result.

[nalle077]

Re: ASUS K50IJ with lp156wh2 no backlight in led

on the LCD board you have GND, put black probe on that and red probe on that burned connector pin. (laptop must be turned on ofc ) post the result.

Thanks for the reply. As you see in the first picture in the thread the whole connector was some kind of burned. I think it is about 7 pins in that connector. I have as I wrote earlier measured over the connector an found 1 pin giving about 10,7V. Should I use some kind of needle to stick it in the plastic to see if the power comes through the cable ? Best regards

[nalle077]

Re: ASUS K50IJ with lp156wh2 no backlight in led

Thanks for the reply. As you see in the first picture in the thread the whole connector was some kind of burned. I think it is about 7 pins in that connector. I have as I wrote earlier measured over the connector an found 1 pin giving about 10,7V. Should I use some kind of needle to stick it in the plastic to see if the power comes through the cable ? Best regards

Anyone with a suggestion? Can I be sure that the problem is in the led? I meen will it be ok if I Change the led ?

[rtstorm]

Re: ASUS K50IJ with lp156wh2 no backlight in led

Can you test LCD from other laptop? I think you must have 19V and 3.3V from mainboard. If this is ok i think canging LCD will help.

[nalle077]

Re: ASUS K50IJ with lp156wh2 no backlight in led

Can you test LCD from other laptop? I think you must have 19V and 3.3V from mainboard. If this is ok i think canging LCD will help.

Ok but is it a standard connector on the motherboard and dont I need a inverter if I test with a lcd instead if a led ? The led screen have no inverter right?

[rtstorm]

Re: ASUS K50IJ with lp156wh2 no backlight in led

Yes you need inverter if you use regular LCD insted LED

[nalle077]

Re: ASUS K50IJ with lp156wh2 no backlight in led

Yes you need inverter if you use regular LCD insted LED

Ok how do I connect that? And is it a standard connector for the lcd/led on the motherboard?

[nalle077]

Re: ASUS K50IJ with lp156wh2 no backlight in led

Ok how do I connect that? And is it a standard connector for the lcd/led on the motherboard?

Is there anybody who can help? Is the small cable on the side in the picture the one for the backlight? anyone with knowlegde of this?

Best regards

[rtstorm]

Re: ASUS K50IJ with lp156wh2 no backlight in led

yes this is the backlight cable, if you want to test with the normaly LCD (not LED) you must have the same connector on that display (that include flex cable with invertor) or you can but this from ebay

[nalle077]

Re: ASUS K50IJ with lp156wh2 no backlight in led

yes this is the backlight cable, if you want to test with the normaly LCD (not LED) you must have the same connector on that display (that include flex cable with invertor) or you can but this from ebay

I found this one. http://www.lcdparts.net/howto/MS493LEDD.aspx what do you think about this. have you heard about this one?

[nalle077]

Re: ASUS K50IJ with lp156wh2 no backlight in led

I found this one. http://www.lcdparts.net/howto/MS493LEDD.aspx what do you think about this. have you heard about this one?

Anyone who have a review on that ?

[nalle077]

Re: ASUS K50IJ with lp156wh2 no backlight in led

Taking up my old thread here now.
I changed a lp156wh2 that was cracked on a friends pc.
The backlight was ok. so I was about to try it in my pc with the lcd with broken backlight. I have no charger for the pc, so I used my other charger and just put it together with a connector that I had(as it was not same connector but same spec charger). And then I did it :$ I put the connector the wrong way :$ in the pc. + were - should be. I did this the right way earlier and all was ok . I put it the right way but now it isnt taking charge What did I break ??? I measured 2 little white fuses on mobo and the were ok help me please.

[rtstorm]

Re: ASUS K50IJ with lp156wh2 no backlight in led

check marked

[nalle077]

Re: ASUS K50IJ with lp156wh2 no backlight in led

check marked

Ok I have taken out mainboard but I guess I need the chematic for the board to find these components. The only thing I find on the board is J6801 that is written on the board. Can anyone help me with a scheme for the mainboard.
K50IJ main board rev. 2.1
EDIT: I found board, but I am not so experienced with how to see the same in schemetic of board on actual mainboard. Anyone with a photo who can point where these components are?
Best regards Nalle077

[rtstorm]

Re: ASUS K50IJ with lp156wh2 no backlight in led

Here is the schematic, please take good photo of that part on motherboard (where is DC jack)