Troubleshooting Guide Display & Screen

Horizontal Lines on Screen – Android Smart TV Troubleshooting

Technician-verified diagnosis, root causes, software repair workflows, and USB firmware solutions.

⚡ Quick Answer

Horizontal colored or black lines across a Smart TV display indicate gate driver COF (Chip-On-Film) failure, tab bonding degradation, or defective source driver ICs. Unlike vertical lines caused by loose LVDS cables, horizontal lines represent internal open circuits on the glass panel substrate.

Common Symptoms

TV powers on but fails to reach home launcher, backlight turns on with no picture, or TV restarts cyclically during boot.

Root Causes

Corrupted boot partition, sudden power outage during automatic OTA update, insufficient flash memory, or faulty eMMC system blocks.

Step-by-Step Diagnostic & Repair Steps

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Cold Power Cycle: Disconnect the AC power cord from the wall. Hold down the physical TV power button for 30 seconds to drain motherboard capacitors. Leave unplugged for 5 minutes, then reconnect.
Disconnect All External Peripherals: Remove all HDMI devices, USB drives, set-top boxes, and external audio cables to isolate hardware interrupts.
Access Android Recovery: With power disconnected, hold down Power + Vol Down on the TV panel, reconnect power, and hold until recovery menu appears. Select Wipe data/factory reset.
USB Firmware Re-installation: If the system bootloader is corrupted, reflash the factory USB firmware via FAT32 flash drive.

When is Firmware Flashing Required?

If soft reset and recovery wipe fail to resolve the issue, the OS system partitions or kernel image have become corrupted. In this scenario, writing clean USB firmware is the definitive method to rewrite the eMMC system partitions and restore normal operation.

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