Symptoms
- Screen flashes once or twice before displaying normally
- Flash happens every single time the TV is turned on
- Flash is accompanied by a brief dimming or brightness change
- Flashing has gotten more frequent or longer over time
Likely causes
- CommonNormal backlight initialization sequenceSome TVs briefly flash the backlight as part of a normal self-test when powering on.
- CommonPower supply capacitors struggling to reach stable voltageAging capacitors can cause a brief flash or flicker before settling, and this often worsens gradually over months.
- PossibleLoose internal connection triggering a brief signal drop at startupA connection that's fine once warmed up can cause a startup flash if slightly loose.
What to do
- Time how long the flash lasts and whether it happens every single power-on.
- Check your TV's manual or model support page to see if a brief startup flash is documented as normal for your model.
- Note whether the flash is getting longer, more frequent, or more intense over weeks, which suggests a worsening power supply issue.
- Power cycle by unplugging for a minute and see if the behavior changes.
- If the flash is brief, consistent, and not worsening, it's likely a harmless part of normal startup.
- If it's worsening or accompanied by other symptoms like random shutoffs, plan for a technician visit.
Tools and parts
TV power supply boardSearch: “TV power supply board replacement for model”
When to call a pro
If the startup flash worsens over time or comes with other symptoms like random shutoffs, have a technician check the power supply.
Safety
Generally low risk
Generally low risk for a careful person. Stop if anything looks different from what this guide describes.