Easy tips for fixing TV picture issues

Home theatre systems integrate a high-definition TV, DVD or Blu-ray player, a satellite box and a surround-sound system. If you have set up your system and used HDMI cables to connect between the components, it should work perfectly — but sometimes it just doesn't. That's because each component must recognize all the others before it makes a connection in a process called the "HDMI handshake." If the handshake fails for any reason, the components won't talk to one another and you'll have no picture or sound.

• Try changing the sequence in which you switch on the individual components of your home theatre system. For example, try turning on the TV first, then the DVD player, then the surround-sound system.
• If this doesn't work, experiment a little and you'll probably find a sequence that works for you.
• Still no picture? You may need to update the firmware (the instructions embedded in the components' circuits). You can usually do this via your system's connection to the Internet.
• Consult your user manuals for detailed instructions.

At present, there are two main systems available for 3-D TV — one is termed "active," the other "passive." With active 3-D, the user needs to wear quite heavy glasses containing electronic "shutters" that let light pass into one eye at a time. In passive systems, users wear lighter polarized glasses. If your 3-D images look ghosted or unclear, there are a few steps you can take.

• In your TV menu, switch off the ambient light sensor (this makes the TV screen brighter if the room is well lit, and darker if light levels fall). Then, toggle through the TV's picture settings while wearing your glasses and select the mode that gives the best 3-D image. You'll probably need to set your TV to a brighter level than for 2-D, because the glasses absorb some light.
• If you have an active system, check that there is nothing blocking the infrared emitters that tell the glasses when to flip their shutters. These emitters often take the form of a "wand" that plugs into the TV, or they may be built into the TV itself.
• Make sure that the batteries in the glasses are fully charged. Some recharge via a port on the TV; others employ a button-type lithium battery, which you'll need to replace once in a while.

• When your viewing is interrupted by a skipping DVD, first try cleaning the disk.
• If this doesn't do the trick, check for scratches. Hold the disk up to a bright light — if the light passes through the scratch, it's probably too deep to fix, and if the scratch runs around the circumference of the disk you may be out of luck, too. However, if the scratch is radial, try the following fix.
• Cover the disk's playing surface with a thin layer of furniture polish; wipe it on gently with a microfibre cloth, working outward from the centre. Using a clean microfibre cloth, buff the surface until it is dry — then try your disk again.