1. Classification of Black Screen Issues and Corresponding Solutions
| Black Screen Type | Accompanying Symptoms | Possible Causes | Repair Cost |
|---|---|---|---|
| Complete Black Screen | Power light off | Power board failure | 50-100 RMB |
| Backlight On, No Image | Indicator light stays on | Main board / Logic board issue | 100-300 RMB |
| Screen Lights Up Then Turns Off | Indicator light blinks | Backlight driver board failure | 80-200 RMB |
2. Step-by-Step Testing and Repair
✅ Step 1: Check Power Issues (Most Basic)
- Action:① Replace with a power cable of the same specification (12V/2A) to rule out poor contact;② Use a multimeter to measure the output voltage of the power adapter (plugged into the TV, black probe to ground, red probe to positive, normal 12V±0.5V).
✅ Step 2: Check Backlight System (Common in LED TVs)
- Phenomenon：Screen slightly bright after power on, displays menu but no image
- Steps:① Open the casing and locate the backlight driver board (the circuit board connected to the LED light strip);② Short the “ON/OFF” signal line (usually a two-pin connector, shorting it keeps the backlight on), if the screen lights up, the driver board is faulty (replace for 100 RMB), if not, the light strip is damaged (requires screen disassembly, recommended to return to factory).
✅ Step 3: Determine Main Board Failure (Requires Some Technical Skill)
- Phenomenon：Power on with sound but no image, indicator light stays on
- Testing:① Use a USB drive to play a video (HDMI interface), if the external signal is normal, it indicates a fault in the main board’s decoding chip;② Before replacing the main board, first power off and restart (long press the power button for 10 seconds to clear the cache, some false faults may recover).
3. Safety Tips
- Always disconnect power before disassembly! Residual voltage in capacitors can cause electric shock (wait 10 minutes for capacitors to discharge);
- Non-professionals should not attempt to solder main board chips, improper temperature control with a hot air gun can easily damage the circuit board.
