2 or 3 of my channels have a picture but no sound......when I use the remote to change the channel I hear sound for the channel for a split second and then it's gone

read instruction manual and or call the customer service for the brand you have, last resort call the store where purchased and see if they will help.

This is controlled by the Split and Swap buttons on the remote; the size of the second picture can be adjusted with the Aspect button. First press split and use the Input button to select the source of the right picture of the split screen (TV channel or video inputs). Then press Swap and use the input button to select the source of the second screen. Swap again if desired or press Aspect to change the size of the main screen window. However, it is not available if you are using the HDMI, PC and SD Card viewing mode. Since the TV doesn't have dual digital tuners, you can't watch two different digital channels on the split screen.

The manual for the Panasonic TH-42PX600U is available from from Panasonic here: http://www2.panasonic.com/consumer-electronics/support/Televisions/Plasma-HDTVs/model.TH-42PX600U . See page 18 of the manual, page 10 of the PDF.

I hope this helps.

Cindy Wells

Hi, Mary with Dish Network Customer Service here. It sounds like when you try to change channels with your remote, it is changing the channels on your TV and not your Satellite Receiver. In the top left corner of the Dish Network remote is an SAT button. When you try to change channels on the Satellite receiver this button should be lighting up. If the TV button lights up, it means the remote is working the TV. Press and release the "SAT" button after you have the picture back on the TV and it should work normally. I hope this resolves your remote issue!

Change the box it will solve the problem.

Try the audio button on the remote. Make sure the SAP is off.
I hope this helps you.

you have to reprogramme the remote, here is the offical site with instuctions and codes for your device:

http://www.universal-remote.net/philipsmagnavox.html

regards and dont forget to rate us!!!!!

Is this a new condition?
Or has it operated differently in the past?

If you are connected to any kind of box (satellite for example), there is only one channel that the TV sees; usually 3 or 4.

The channel changes are limited to the box.

Try plugging your cable box in using a/v cables (red,white,yellow) and see if you have a picture on a different input from the box. If so, go into your general settings in the box and change the output channel to 4 instead of 3. Then try your TV on 4 and see if your picture comes in. I have seen TV tuners go out on just one channel before.

make it sure you're on the right atenne, if not you can use both...

try changing the channel with the original remote or by the tv's physical controls. It sounds like it has switch to an AV channel.