TV sound and picture out of sync

A soundbar, Bluetooth connection or particular source may introduce delay.

Never open TVs or power supplies. Stop using them if there is a burning smell, smoke or crackling. Do not disconnect power during an update.

Try another channel or app. If only one source is affected, it may be responsible.
Temporarily select the TV’s built-in speakers. If they are in sync, investigate the soundbar or headphone connection.
Look for Audio delay or Lip sync in the manual. Note the original value and change only one setting in small steps.
Restore a setting if it does not help. Do not enter random service-menu codes; record device models and connection type for support if the fault persists.

Test after each step and stop when the issue is solved. Checkmarks are not permanently saved.