- Intermittently and irratically, the TV picture will freeze and the sound will stop, both together but momentarily, and then both will resume
- When the TV picture freezes it will look blocky, pixelated, or infested with small squares of unrelated random video patterns (macroblocking)
- The sound may studder, stammer, or come and go
- A message may appear on the screen saying something like "No connection", "Check Your Cable", "Invalid Signal Format" or "Weak Signal"
You are watching streaming video with the TV connected to the internet
See WiFi Connectivity.
You are watching satellite TV
- The satellite dish may not be aimed properly. Satellite dishes are very directional, and can only see the narrow spot in space to which they are focused. They need to be aimed at the precise location of the satellite, a very tiny point in the sky. Any movement of the dish (such as caused by wind) will cause the received signal to fluctuate in strength.
- Heavy rain will attenuate, or weaken satellite signals. The only solution for that is to wait for the storm to go away.
- Poor cable connections between the TV and the satellite dish can also cause intermittent reception. See Senario 4.
The TV is connected to an indoor antenna, and the picture and sound comes and goes on one or more channels.
The TV is connected to an outdoor antenna or aerial, satellite receiver, or a cable set-top box, and the picture and sound comes and goes on one or more channels (perhaps more frequently during windy or rainy weather).
Connectors on coaxial cables can become loose or faulty and cause poor signal problems, especially when they are outdoors, exposed to the elements of nature, where rain or moisture can get in and short out the signal. Connectors can also become intermittent or go completely bad if they have undergone excessive tention. Cables should be dressed against structures or suspended in such a way so as to provide adequate strain relief at the connectors.
Unscrew and inspect each connector that you find. If you find moisture in any connector outdoors, there are three approaches you can take. The quick-fix approach is to simply blow forced air into it to displace the water, or spray some electrical contact cleaner or solvent into the male connector.
A better solution would be to replace the connectors with new (dry) ones, along with any double-female barrel adapters (which are used to spice two cables together). To do this you will need to cut off at least six inches of cable from the end. Then you will need a knife and a special crimping tool to prepare the end of the cable and crimp the new connectors on the ends. Replacement F-connectors and a crimp tool for RG-59 or RG-6 cable can be found in any major hardware store.
The best (easier but more expensive) solution might be to replace the cable with a new one that already has the connectors on it. If you do this, be sure to get either type RG-59 (good) or RG-6 (best) cable. And if it's going outdoors, get the kind that is specifically made for exterior use. Lastly, the all-metal connectors are superior to the plastic grip connectors that are molded to the cable.
The picture and sound comes and goes while watching TV from a cable TV system, cable set top box, DVD player or Blue-ray player
For this you will need to know how your TV is hooked up. See How Is My TV Hooked Up? if you're not sure. If you have more than one source connected to the TV, such as a DVD or Blue-ray player, switch to a different source and see if the same thing happens. If the probem occurs all the time no matter what source you are watching, you'll need to have a TV service technician come and look at your TV.
If it's just happening with one source, and the source is connected with a coaxial cable to the antenna or cable input, then the problem is a weak signal coming in from your antenna, cable box, or satellite receiver. This kind of problem may occur on all channels, some channels, or even just one channel. The cause is usually a faulty cable connector. See Senario 4 for what to do. If the problem occurs when the weather was rainy or windy, the faulty connector is somewhere outside.
If the problem occurs with a source connected via an HDMI cable, the problem is most likely not the HDMI cable, but a bad cable connection upstream from your set-top box, and you would follow the advice given in Senario 4. But in rare cases there have been HDMI incompatibility issues with TVs connected to cable TV set-top boxes and satellite receivers. If it’s an HDMI incompatibility issue, your cable or satellite TV service provider has done something to change the software in your set-top box. There may be a software update that can be performed on the TV that will cure the problem. See Software Updates for TVs on how to do that. If the latest software is installed in your TV and you still have the same problem, then you need to contact your cable or satellite TV service provider, because the problem is not with your television.
The picture or sound is intermittent because of a faulty cable plugged into the TV, or because of a faulty connector (jack) on the back of the TV itself.
Cables can become intermittent or go bad at their connectors. This can happen when the cable is disconnected repeatedly by grabbing it by the cable itself and yanking, rather than grasping the connector to disconnect it. Repeatedly unplugging and plugging in cables can also damage the female connector on the TV causing an intermittent connection as well. To tackle this problem you will need to gain access to the printed circuit board (see How Do I Get To the Circuit Boards in a TV?).
If the connector does not feel loose when you rock it back and forth, but the connection comes and goes, then there is probably a hairline fracture on the printed circuit trace to which the connector is soldered. If this is the case, then the board will either need to be repaired or replaced. It can be repaired by locating the broken trace, scaping the solder-resist off of the trace on either side of the fracture to expose the actual copper trace, and then reinforcing the trace with solder. If the connector feels loose to the touch, then it is likely that the printed circuit board has a crack in it, and will need to be replaced.
The printed circuit board in your TV that would most likely cause these kinds of issues is called the 'Main Board', or 'Signal Board'. It is generally the one that is populated with all those connectors for connecting various devices to the TV that are accessible in back of the TV.
Sometimes the failure could be caused by the actual connectors (jacks) on the printed circuit boards themselves. They can become electrically intermittent due to excessive mechanical stress from either 1.) the wear and tear of constantly plugging and unplugging cables into them, or 2.) the constant physical weight or tension imposed on them by the cable.
Whether the problem is with the board-mounted connectors, or some other component on the Signal Board, the board would definitely need to be replaced, and this web site can show you how to replace it. The articles How Do I Get to the Circuit Boards? and Replacing Circuit Boards in a TV provide useful information.