Test LCD of a cell phone

How To Test LCD of A Cell Phone

It is not difficult to check LCD (Display) of a cell phone or a tablet. LCDs being delicate tend to crack, leave blots or simply sop working. So if its is broken or cracked, you can see its broken manually. Even if there is a blot on it, you can see it physically. But what if its looking good and still there is no graphics on the display? The problem may be either the LCD is faulty or there is some problem in the PCB. So how do we test it?


A faulty LCD can be of the following types:

  • Cracked or broken
  • A blot (round in shape which will spread rapidly!)
  • Blank display with no graphics.
  • An LCD with just graphics and no light (LED) glowing on it.


You can check LCD of a cell phone by any of the below methods


1. LCD Testers: There are testing machines available in the market for checking of LCDs. The problem here is that as all models have different LCDs, you will need to buy an LCD tester machine for all types and models and will run into hundreds! As all LCDs of smartphones,  be it an iPhone or a Samsung Galaxy or an Xperia have different size connectors, with varying no of connecting pins, a universal LCD checking machine cannot be made. This is a major constraint and hence not at all feasible unless you deal in repairs or testing of thousands of units of a particular model.


2. Check it in same model cell phone: The second option is if you have a working handset of the same model, you can easily put your LCD into that handset and check if its working or not. For eg. If you want to check the LCD of your iPhone 5s, you can check it in a working iPhone 5s. So what if you do not have a working handset of the same model. Read the last option!


3. Check with a new LCD: Replace your LCD with a new one. If graphics appear on the LCD, that will mean your old LCD is faulty. And if the new LCD also is not displaying graphics, it will mean your old LCD may be ok. And the problem may be in the PCB. The problem may be in the LCD connector, its connections, PCB or an IC controlling the display function.




1. You cannot check LCD with a multimeter or an oscilloscope!


2. In Samsung phones, you can also check clarity of the screen with the code *#0*#. You can check red, green and blue colours with this code.


3. As regards to being original or duplicate, its better to buy them from good and reputed vendors. Again, if you have many LCDs, you can switch on the handset and compare the clarity with various LCDs yourself.


4. If no light (LED) is glowing, please check LCD brightness settings first before opening your mobile phone.


Please also let us no your suggestions and opinions.