When you say “I find another seller, order another screen.. i receive the same screen.. same issue ! no backlight..” what do you mean? The same screen as the original or the same as the 1st replacement screen that didn’t work?
It may be that the replacement screens wiring connections are different to the original screen.
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Here’s the [https://datasheetspdf.com/pdf-file/909040/LG/LP156WF4-SPH1/1|datasheet] for the original screen. On p.8/31 there is the pinout information. It shows that the ''LED backlight On/Off wire is on pin 22.'' This is the lead that is used to signal the screen to turn the backlights on and off. The power for the backlights is always available at the screen (see pins 26-29) and the backlights are turned on and off as required by a signal voltage being applied or removed on pin 22 as required.
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Here’s the [https://datasheetspdf.com/pdf-file/909040/LG/LP156WF4-SPH1/1|datasheet] for the original screen. On p.8/31 there is the cable pinout information. It shows that the ''LED backlight On/Off wire is on pin 22.'' This is the lead that is used to signal the screen to turn the backlights on and off. The power for the backlights is always available at the screen (see pins 26-29) and the backlights are turned on and off as required by a signal voltage being applied or removed on pin 22 as required.
If neither of the replacement screens are the same model as the original you would have to find the datasheets for those screens to check what their cable pinouts are to see if it is compatible or not. Search for ''(insert full make and model number of screen) pinout'' to hopefully find the datasheet
Since the original screen backlights still work when it is connected it is not a backlight power supply problem from the motherboard, it may be a compatibility issue instead
Here are the [https://asusparts.eu/en/partfinder/Asus/Notebook/N%20Series/N550JK|parts] for your laptop. If you click on ''Category > Display'' you will find the part numbers for the screen. If you search online using the Asus part number ''only'', you will get suppliers of the part. At least it should be compatible.
When you say “I find another seller, order another screen.. i receive the same screen.. same issue ! no backlight..” what do you mean? The same screen as the original or the same as the 1st replacement screen that didn’t work?
It may be that the replacement screens wiring connections are different to the original screen.
-
Here’s the [https://datasheetspdf.com/pdf-file/909040/LG/LP156WF4-SPH1/1|datasheet] for the original screen. On p.8/31 there is the pinout information. It shows the the ''LED backlight On/Off wire is on pin 22.'' This is the lead that is used to signal the screen to turn the backlights on and off. The power for the backlights is always available at the screen (see pins 26-29) and the backlights are turned on and off as required by a signal voltage being applied or removed on pin 22 as required.
+
Here’s the [https://datasheetspdf.com/pdf-file/909040/LG/LP156WF4-SPH1/1|datasheet] for the original screen. On p.8/31 there is the pinout information. It shows that the ''LED backlight On/Off wire is on pin 22.'' This is the lead that is used to signal the screen to turn the backlights on and off. The power for the backlights is always available at the screen (see pins 26-29) and the backlights are turned on and off as required by a signal voltage being applied or removed on pin 22 as required.
If neither of the replacement screens are the same model as the original you would have to find the datasheets for those screens to check what their cable pinouts are to see if it is compatible or not. Search for ''(insert full make and model number of screen) pinout'' to hopefully find the datasheet
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Since the original screen backlights still work when it is connected it is not a backlight power supply problem from the motherboard, it may be a compatibility issue instead
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Since the original screen backlights still work when it is connected it is not a backlight power supply problem from the motherboard, it may be a compatibility issue instead
Here are the [https://asusparts.eu/en/partfinder/Asus/Notebook/N%20Series/N550JK|parts] for your laptop. If you click on ''Category > Display'' you will find the part numbers for the screen. If you search online using the Asus part number ''only'', you will get suppliers of the part. At least it should be compatible.
When you say “I find another seller, order another screen.. i receive the same screen.. same issue ! no backlight..” what do you mean? The same screen as the original or the same as the 1st replacement screen that didn’t work?
It may be that the replacement screens wiring connections are different to the original screen.
Here’s the [https://datasheetspdf.com/pdf-file/909040/LG/LP156WF4-SPH1/1|datasheet] for the original screen. On p.8/31 there is the pinout information. It shows the the ''LED backlight On/Off wire is on pin 22.'' This is the lead that is used to signal the screen to turn the backlights on and off. The power for the backlights is always available at the screen (see pins 26-29) and the backlights are turned on and off as required by a signal voltage being applied or removed on pin 22 as required.
-
If neither of the replacement screens are the same model as the original you would have to find the datasheets for those screens to check what their cable pinouts are to see if it is compatible or not. Since the original screen backlights still work when it is connected it is not a backlight power supply problem from the motherboard, it may be a compatibility issue instead
+
If neither of the replacement screens are the same model as the original you would have to find the datasheets for those screens to check what their cable pinouts are to see if it is compatible or not. Search for ''(insert full make and model number of screen) pinout'' to hopefully find the datasheet
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Since the original screen backlights still work when it is connected it is not a backlight power supply problem from the motherboard, it may be a compatibility issue instead
Here are the [https://asusparts.eu/en/partfinder/Asus/Notebook/N%20Series/N550JK|parts] for your laptop. If you click on ''Category > Display'' you will find the part numbers for the screen. If you search online using the Asus part number ''only'', you will get suppliers of the part. At least it should be compatible.
Hi @ramoglio123
When you say “I find another seller, order another screen.. i receive the same screen.. same issue ! no backlight..” what do you mean? The same screen as the original or the same as the 1st replacement screen that didn’t work?
It may be that the replacement screens wiring connections are different to the original screen.
Here’s the [https://datasheetspdf.com/pdf-file/909040/LG/LP156WF4-SPH1/1|datasheet] for the original screen. On p.8/31 there is the pinout information. It shows the the ''LED backlight On/Off wire is on pin 22.'' This is the lead that is used to signal the screen to turn the backlights on and off. The power for the backlights is always available at the screen (see pins 26-29) and the backlights are turned on and off as required by a signal voltage being applied or removed on pin 22 as required.
If neither of the replacement screens are the same model as the original you would have to find the datasheets for those screens to check what their cable pinouts are to see if it is compatible or not. Since the original screen backlights still work when it is connected it is not a backlight power supply problem from the motherboard, it may be a compatibility issue instead
Here are the [https://asusparts.eu/en/partfinder/Asus/Notebook/N%20Series/N550JK|parts] for your laptop. If you click on ''Category > Display'' you will find the part numbers for the screen. If you search online using the Asus part number ''only'', you will get suppliers of the part. At least it should be compatible.