My tv changes channel by it self

Channel change button on the remote or on the side of the TV coule be stuck.

When heats up, the supply voltage from the main power supply board goes less. Check all the soldering to this board for any loose solder terminals. Resolder all the suspected solder terminals by applying a little more solder. If it do not help you, replace the board as card basis.

the problem of your TV is the button of the channel will not getting back so channel can't stop

you have to do is replace the button if you will or use a remote control to access the channel and never use manual changing channel again

Hello, in many cases, a malfunction of the TV

Pull out the power plug of your TV and don't use it for few minutes. Remove batteries from your remote and keep it without batteries for few minutes. After about 15 minutes your TV and remove both will work fine.

the variation from higher channels from lower channels, few things changes eg frequency, voltage, and current.
take your tv to a w/shop and have the following
tunner voltage pulse variation on a avo meter has you change channels. if the difference of voltage is not unform when you are changing from to channel then you should change the control ic on the rf stage or check the capacitors a round the rf ic for variations in value.

Be sure your remote hasn't got a button stuck down which is changing channels. If not, take the batteries out of the remote. If this stops the channel changing there is probably some conductve material stuck across the circuit board
inside the remote. If this is the case you have to check inside the remote by openning it up.

the problem is there is engaged button there..only technician can do the job by replacing the button that is always engage.

There are a few things that can cause this. #1 most often cause is either something spilled on the channel button or something wrong with the bezel where the buttons are located causing the button to be pressed all the time. Check the buttons on the tv and make sure none of them are stuck. #2 is a bad button (switch). Replace the switch or the control board. #3 is a short on the wiring harness going from the switch to the mian board. Maybe it's squished against the frame somewhere. #4 would be a bad main board. You will likely have to take this unit to a service centre to have it looked at.

I have seen some RCA TV's with this problem and it has usually been a switch going bad on the keypad of the tv. This can be confirmed by disconnecting the plug from the control panel to the main chassis.If you are lucky, and the ir rcvr for the remote is not on the control board, you can still control tv with the remote.Good luck.