No sound on 3 channels

make sure set not set to sap mode as this can blank audio on certain channels

1.) Check its not muted/ the sound is all the way down
2.) If the TV has seperate speakers make sure they are plugged in to the main unit.
3.) If you are watching tv change the channels, if any channels have sound then the one you were watching has lost signal, try retuning.
4.) If all these have failed your TV may be on the way out :(

Maybe the cable signal is defective not your tv.the other channel is ok.if you tv has a defect all channel has affected.

switch the cable box from one tv to another one see if the box you changed works on the tv set you removed the cable box from on all channels if it does work after you swap out the box then it has to be bad!!!
techman

cable signal is weak. Tech. must check house wiring.

boomergal, do you have satelite cable or directv or dish?

I diconnected a recently acquired Panasonic DVR which was hooked up between my TV and the cable signal source, but this had no immediate effect on the two channels. I then reset the TV by unplugging it over night, and by changing the settings on the sound menu. These actions removed the problem. Is it possible that the DVR caused the problem?

Access the customer menu, select cable vs. ant then go to auto programming and let it do it's magic.
Bill

I personally would get myself a "Universal Remote". These units will operate almost ANY unit that uses Infrared... Ya Punch a "Code" in for your particular TV etc, and thats it... total conrtol...

What you need to do is take the remote, go into the menu, find channel scan and do a channel scan to find all the available stations available on this system. Make sure the TV set is in the cable mode and not antenna mode or you wont get any stations above channel 13.