Just got a new flat screen 42" phillips and it is not picking up the cable box after 4 tries. Called cable company and they said signal was fine and box was correct to use for TV.

If DVD input works likely a issue with the signal.

If using a cable or sat box or even a receiver inline--unplug each and after several minutes plug back up to allow each unit to try to reboot.

If using component connections from box or receiver they may be the issue or not. In that case if a box is feeding signal via component or even HDMI the box (if reboot does not fix this) may be bad.

Another simple test if cable is used with a box is disconnect cable going to the box and connect directly to set--that way you will know if box is or is not the problem.

If your trying to receive over the air make sure the TV is not set to a Cable mode, if your on Cable your new TV is most likely a ATSC tuner (digital) and the cable company can map channels any way they want. If your old TV had the older style cable tuner, the lineup will be different.
HDTV has level thresholds, if the signal is weak you wont see anything, but the old TV would.
Without knowing much about where or what sort of TV your using, these are my best ideas.

Call your cable company as there might be a problem with the drop line or aerial coming into your house. now another thing is if you have a signal splitter( ex: 2-way, 3-way, 4-way) before the cable box, that could be degrading the signal as each input may drop the signal significantly. remeber, don't use too many splitters as they will make the signal faded/fuzzy. also, make sure all the connectors are clean and are not badly bent or the ends frayed. If you can see wire insulation from the cable line then it's no good.

try reset to defaults:

1. Press the 'MENU' button.
2. Press the cursor down to select SETTINGS.
3. Press cursor right twice.
4. Press the cursor down to select RESET AV SETTINGS.
5. Press cursor right on START NOW. Press the 'OK' button.
6. Press the 'MENU' button to exit the menu.

You can have your plasma repaired using a TV Repair guy but often it costs as much as a brand new LCD. My daughter broke my $1,600 LCD. It would have cost $1,200 to fix.. so I just bought a new one.After that I picked up a TV screen protector called TV Armor http://www.tv-armor.com Its designed to protect the TV from damage. Now I dont have to worry anymore when she is playing near it. It works really well.

Eric

try the lead in another slot and even another lead, if problem persists demand an engineer comes out.

It sounds like the cable modem is flaky. Have you called the local cable company to report the problem. This should be a no-cost solution.

Had the problem. Turned out to be a defective hdmi port circuit board.

if normal tv is fine then ,likely the signal from the box is too hot.
if using composite switch to cable ch 3 or vice versa,
or use hdmi cable or change the box .

For most cable services, you need their decoder box to have the digital and HD services.

For the Sony HD TV, you will get best results with an HD cable box, and use the HDMI cable interconnect with it.

Call your cable company for details.

Jerry G.