A scrambled picture on your digital TV can be caused by several factors including whether or not you are using a broadcast TV source or cable TV service. Scrambled TV images may also be caused by a weak signal being sent to your digital receiver or digital receiver box that has an overcharged capacitor.
Digital TV Transition
The Federal Communications Commission eliminated all analog television broadcasts on June 12, 2009 and replaced them with Digital TV broadcasts. A digital TV converter box is required to view digital TV transmissions received through all over-the-air antennae. Analog TV sets without a digital TV converter box will not be able to view DTV broadcasts and may result in a scrambled image on your screen. High-Definition TVs with a built-in digital tuner are able to view over-the-air broadcasts without a converter box.
Cable and satellite companies can scramble channels that you have not subscribed to. Several cable and satellite companies require their customers to use a digital cable box to view subscription channels. Prior to the introduction of digital cable transmissions, analog filters would scramble and decode subscription channels provided by your cable company.
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A weak signal being transmitted over your home's wiring may also cause scrambled images on your TV. Digital TV transmissions operate between the 900-2150 Megahertz frequencies, while analog TV transmissions typically do not exceed 900 Mhz. Your signal may be degraded due to excessive wire splitting inside of your home. Wire splitting gives you access to more cable outlets, but can degrade your TV signal by up to 3 decibels per line. Cable TV amplifiers can be used in conjunction with Digital TV splitters to increase the signal strength to TVs with scrambled pictures. Replace any analog TV splitters or amplifiers with ones tested for Digital TV transmission for best results.
Power Cycling Your Equipment
Your electronic devices will gradually store information in their random access memory with use. Sluggish performance and scrambled TV pictures can be a result of buildup in your device's memory. Power cycling your equipment discharges the information stored in your devices memory and can solve problems with scrambled pictures on your TV. To power cycle your equipment, unplug your TV and your cable or digital TV converter box for at least 10 seconds. Power cycle any devices connected to your boxes, including residential gateways and wireless modems. Plug the devices back into the power supply after 10 seconds and wait for them to restart. Power cycle your equipment weekly to prevent future problems.