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Sony Bravia Screen does not power on red light flashes 4 times

From Repair Wiki
Sony Bravia Screen does not power on red light flashes 4 times
Device Sony Bravia KDL-40W2000
Affects part(s) Main Logic Board
Needs equipment multimeter, soldering iron, soldering station
Difficulty ◉◉◉◌ Hard
Type Soldering

Problem description

Fixing an issue where the screen does not power on, red light flashes 4 times on the Sony Bravia KDL-40W2000


  • Screen does not power on, red light flashes 4 times.


This error is generally to do with protection related to overheating. Either the PSU is overloaded, the backlight power source/inverter is drawing too high a current, or a temperature sensor / related sensor has tripped.

  • Lie face down on a towel, remove bottom stand such that screen lies flat on towel.
  • Open rear and remove dust from PSU board. Careful any charged caps
  • If very dusty, remove PSU completely and dust with a brush (especially backside)
  • Ensure MOSFETs and diodes connected to heatsinks have thermal paste and are tightened accordingly.
  • Replace any swollen caps on PSU.
  • If it is a plasma backlight model, check the high-voltage connector plug between PSU and Inverter. Clean inside of plug ends with contact cleaner. Ensure cable is secure.
  • Check all axial fans that have 3 wire leads. If the mainboard detects RPM of any fan is too low, it will trip as an overheat warning. Replace fans if necessary.
  • On completion, reassemble case. Hold down Power button and Volume Down button and keep holding while you plug in the power cord. The light should flash green indicating a reset has completed successfully.