Stuck on 3 channels, no remote.

sounds like you have an intermittent defective main board. ebay rca model for replacement board.

if you turn off at wall. leave for 3 min put power on and hold down volume up and down wile pressing the power button see if that works.

Try website like Remotes.com to buy the tv original remote to used.U will used the tv original remote to turn to channel 3 with ease.After u have the tv original remote push the menu button go into Closed Captioning functions turn off like TEXT 1,2,3...The big black box will not appear on the screen again.Tv used it manually control buttons up and down channels trying to get to channel 3.U will never get it to tv channel 3 because tv channel 3 was not save on it memory list of on the tv turn manually channels buttons programming memory.Tv have a manual button said MEMU button on it tv front bazel frame?Yes.Might could used the Menu button on the tv frame to get in to turn off TEXT 1,2,3...to stop the big black box to show up on the tv screen again.

U still have the tv original remote?Yes,must used it to get into chanel 3.Because the manual buttons channels up and down on the tv bazel frame will skip channel 3.Only able get into channel 3 by manual channel buttons up or down only if it was save in the tv memory.Try website like Remotes.com to buy the tv original remote.

I have just got a kv-20s43 and your best bet is to try to restore settings, here, To reset TV to factory settings, turn the TV on, Then, while pressing the reset button on the remote control, press POWER on the TV. The TV will turn itself off, then back on, the original settings wiill be restored... definition: ch. fix- 2-6: Select when you want to control all channel selection through a cable box. Select the appropriate channel(usually 3 or 4) and use the cable box's remote control for channel selection. VIDEO: select from available inputs when you have connected video equipment and you want your TV fixed to it.

Enter "3" or "03" on the remote and press OK/Enter.  If the channel-skip feature is set on for Channel 3 you cannot get to it using the up/down buttons.  Go to the setup menu to disable the channel-skip for Channel 3 if you want to tune it with up/down buttons.  If you have no remote you should be able to access the menu from buttons on the front of the TV. (They may be inside a door or panel.)

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.

Check to make sure the channel down button is not stuck. If it is not the button is probably defective. Mits has had a lot of problems with the buttons.

found solution by holding down both volume buttons at same time which enables on-screen menu allowing to select channel auto program

Found this in another forum (www.hometheaterspot.com) and it fixed my remote problem:

"...it's possible that one of the front panel buttons is "stuck" or shorted, and this could cause the TV to ignore commands from the front panel or remote. But this should also cause the Power command to be ignored, too. You might try pulling off the front panel and disconnecting the front panel buttons and then see if the remote works."