**There can be two causes:**

 1. Hardware failure. Unlikely, but a possibility.
 2. **Each device has multiple sub-models, and each sub-model has multiple roms**. You need to be sure you're installing the Rom meant for your exact device model, even if you are re-installing a Stock Rom. If you do install a rom not meant for your device, you often face issues like these.

     The solution for this is to first **confirm your exact device model**:

    - Boot into your device's bootloader and look up the device version/model.
    - Open the download page of the Rom you installed
    - Download the version specific to your model
    - Install the Rom the usual way, but be sure to do full wipe/clean of all partitions first from the Recovery.