I. Power & Startup Faults (Most Common)

1. Failure to Power On / Black Screen / Low Battery Alarm Only

• Does not power on with AC power, no indicator light;
• Shows “battery voltage low” and fails to start on battery only.

• Power not connected / defective battery
   
  Check AC adapter, power outlet and power cord;
   
  Battery aging (service life: 1–2 years): voltage < 11V, unable to charge → replace the battery.
• Damaged power board / fuse
   
  Internal power fuses (F1/F2) blown, short circuit on power board (bridge rectifier, TOP227Y, etc.);
   
  Solution: replace fuse / power board (professional maintenance required).
• Poor connection between power switch board & mainboard
   
  Loose cable between switch board and mainboard → reconnect the cable.
• Power protection (short circuit of external devices)
   
  Disconnect all peripherals (modules, USB drive, mouse) and retry startup.

2. Automatic Shutdown / Reboot After Startup

• Poor battery contact, unstable voltage;
• Abnormal power board output, overheating protection of mainboard;
• Internal short circuit (module rack / mainboard).

II. Display Faults (White Screen / Garbled Screen / Black Screen / Dim Backlight)

1. White Screen / Blurry / No Image but Backlight On

• Loose / oxidized LVDS screen cable;
• No signal output from mainboard, faulty display driver board (inverter).

• Power off and reconnect the screen cable;
• If problem persists → replace display driver board / LCD screen.

2. Backlight On but No Display / Black Screen (Indicator Light On)

• Damaged backlight driver (high-voltage board / LED driver);
• Loss of 12V screen power supply, faulty GPU on mainboard.

• Test 12V screen power supply; no power → check power board / mainboard;
• Power normal → replace backlight board.

3. Garbled Screen / Vertical Lines / Flickering Screen