LG

  1. Press and hold the Settings button on the remote (first, the menu appears and after a few seconds it vanishes again and the channel id appears in the top left, that's when you have to release the button)
  2. Type 1 1 0 5
  3. Press OK

(If your remote doesn't have a Settings button, try Menu or HOME.)

Philips 26HFL5870D and similar

(Only works if TV is in "Standard" security mode.)

  1. Press the following keys in sequence:

    3 1 9 7 5 3 MUTE