Chosen Solution
Hi guys, my laptop (Asus N550JK, with touch screen - digitizer on the top of a matt lcd) Lcd broke down few weeks ago (purple/green tint etc) after some test i got convinced that the screen was faulty and decided to change it. The screen is lg philips lp156wf4-sph1 (written on it) and it seems to be matt and IPS, so i ordered one online and installed it (I received a BOE screen), the display “works” but there is no backlight.. so i don’t see anything, appart if i put a strong flash on it.. I find another seller, order another screen.. i receive the same screen.. same issue ! no backlight.. I dont know what is the problem, the when i pug in the former damaged screen (an LG philips) the backlight works smoothly (but the screen is broken heh.. as the former still has backlight, issue does not seem to come from motherboard, or lid switch) What could be the cause of it .. ? Thanks in advance for your precious help
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 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 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.
