| 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
Symptoms
- Screen does not power on, red light flashes 4 times.
Solution
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.