Depending largely on the age of the TV, the location of the TV tuner varies. An older analog TV tapping a digital signal does so with an external DTV converter box. For cable and satellite subscribers, there is a a set top box. Most TVs purchased after March 2007 have built-in digital tuners. Look on the front and back of the TV for a marking that indicates a digital tuner. It may say ATSC
, DTV, HDTV, Digital Ready, HD Ready, Digital Tuner, Digital Receiver, Digital Tuner Built-in or Integrated Digital Tuner. Any of these is an indication that the TV has a built-in digital tuner. You may have to go to the manufacturer's site to determine such specifications. If you are having a problem with a tv switching channels, remedies may be rather specific and you might try googling for a specific model while including the problem in a simple phrase.