My samsung ps42c91hdx/xsa tv wont tune in the high def channel 10. the tv can't find it. My sons tvs are picking it up so it cant be the signal.

Are you trying to get over the air channels? IF you are does your TV have the digital tuner on analog? TV went digital and if you have an analog tuner will need either e new TV or converter box.

This could be too much signal.

Just to be sure though, try the set in another room where one of the other TVs works okay. This will help you see if it's a cable or a TV signal issue. If you pick up all the channels okay it's likely that that other TV point has some bigger signal losses due to the cabling.

The mux (transmitter channel) carrying the BBC signals will be amongst the strongest at each and every TV transmitter across the land. This is because the BBC and the main ITV channels have to reach about 96% of the mainland UK population in order to the broadcasters to fulfill their remit.

TV tuner sensitivity varies between brands and models. It may be that your old TV was just about okay with the signal power, but the new TV's tuner is over saturated.

A simple and inexpensive diagnosis tool is a variable attenuator. The MA1620 on this page is perfect for that job:
Splitters amplified splitters and attenuators

It will give you a way to reduce the signal level at one TV without affecting the other TVs in the house.

The converter has only one tuner, this means it can only tune one station or channel at a time. The output of the converter is usually a single coaxial cable jack. The output is generally a user selected channel - often Ch 3 or Ch 4. When you connect the output of the converter to the antenna input of the TV, you set the TV channel to match the setting on the converter (again, Ch 3 or Ch 4).

You could install an amplified splitter to split the output of the converter and run a cable from each TV to the splitter, more on this amplified splitter, later. Set all the TV's to the same channel as the converter output (Ch 3 or Ch 4) and you would be able to watch whatever the converter is tuned to. This means ALL the TV sets must watch the same channel. What is showing on one will be shown on all. This may not be a problem if you live alone and own 4 TVs. You could simply turn one TV off when leaving a room and turn on another when entering a new room. This will be a problem if there are two or more people in the house that wish to watch different programs at the same time. To accommodate everyone, you would need as many converters as there are different programs that are to be watched on different TVs at the same time - 4 would be a good choice to provide the greatest flexibility of tuning for every TV.. You would simply install the additional converters on the other TVs just as you did with the first TV.

If you wish to use a splitter to divide the output of the converter to several different TVs (or have a single antenna and want to send the signal from it to several TVs for that matter), an amplified splitter is highly recommended. A standard splitter only divides the signal and has no provisions to boost the signal from the antenna. The more ways a signal is split, the less signal there is to supply to the TV sets. The result is a snowy picture. An amplified splitter not only splits the signal the way a standard, non-amplified splitter does, but also boosts the signal from the antenna to each TV. This provides a much stronger signal to the TV which results in a better picture. Pick an amplified splitter that has enough output jacks (based on the number of TVs you wish to connect).

I hope this helps and good luck!

U have more than one tv?Yes.Tries check on the other tvs see if u have channel 82 freeview channel,freeview channels are take out or add on all the times by the tvs stantions broadcasting listing.If yes channel 82 is on the other tvs.Than u have low or weak antena signal.U have a analoge antena probally correct?Buy and install a digital antena,u will get a stronger longer ranges tvs incomming broadcasting chaanels tvs stations.Rescan for channels again,u will pick up channel 82 if it still on the air.

On the old TVs, to display a video signal the TV must be tuned to Channel 3 or Channel 4. Some TV have the video channel on Channel1.
Connect the console to the TV, tune the TV to Ch 3 and then to CH4 to find out out which is the video (or auxiliary input) channel.

Make sure your using a cable box that is compatible with a high def tv, if your tuning a high def channel and your converter does not support high def, it will only play the sound, no vidio at all.

OK. This should be simple. If you are using a TV with a built in digital tuner like all the HDMI ( High Defintition Media Interface) flatscreens then you probably need to go through your set up menu on your Digital TV and select Initial Setup / Channel Input / Cable / Satellite if coming directly from a dish on 75 Ohm Coax / or Cable if coming directly from the outside 75 Ohm coax with analog signal. ( When I say DIRECTLY, I mean you are not going through any boxes and changing or passing the signal). All satellite direct connects are digital and all satellite converter boxes have multiple out puts these days. There is an HDMI output for high def and low def analogl to digital (A/D) signals coverted within the TV, sometimes there is a DVI or even a USB out put connector...and there is a 75 Ohm coaxial RF cable connection for all the old schoolers who do not have a widescreen digital TV. RF means Radio Frequency and uses Radio Frequency Channels 3 and 4 at the bottom of the RF band around 56 MHz to which any TV with an Analog Tuner can use. In the old days this is what was used for the connection to the TV from the cable boxes because our TVs did not have the capability of decoding analog pay channel signals, hence the little black boxes sold and used ONLY by cable thieves and not any of us here on fixya. For starters, let's make sure you are using your high def, dvi. or some format of digital It sounds like your TV is set up to search and code digital signals but is looking for the wrong carrier frequencies, meaning it is either looking for decoded digital satellite box signals, digital broadcast ( New Digital TV received via an Antenna). Once your TV scans for channels in the cable mode they will be memorized and available on your channel up / down keys and Favorites. (FYI t will scan for both digital and analog channels on antenna mode). Repost if you have troubles or refer to your users manual.

When I installed my dads Samsung 40 lcd 120 hz. I had to turn it all off and after 5 mins I turned on the cable and then 5 minutes later I turned o the tv.

Or have you tried "searching" the tv for cable channel's?

try tuning tv in another room, if it works it is then your cable or socket, try the cable next. If it wont tune its a faulty set.

IYou have to have your comcast box tuned to a channel that is broadcast in HD. On your Comcast remote hit menu. This will bring up several icons, one is HD. Select that icon and it will bring up the TV Guide for just HD channels. Select one and tune to that channel. Once your on that channel use your original remote and hit menu, then advance features, then go down to video display and change it from 480 to 980 or 1080. Let me know if this helps.