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I have a Panasonic TV, model number 55CX400U TV. The TV has a GREAT picture……… the problem it has is that the picture will stay on for maybe 5 minutes and it goes dark. I can then try and turn the TV back on, and after 3 attempts it will turn back on. This goes on for about 3 to 4 times and then it will run all day long without the problem. I was beginnig to think it was the backlight, but if the LED strips were bad, I would think the set would go out and STAY out. And also, the set responds to its remote control very erratically….. I can sometimes press a button on the remote and it will take a few MINUTES to respond to input. So I am thinking can it be a bad mainboard causing the TV to go dark? I’m perplexed….if it did not have such a good picture I would not bother..but this is not my main set and I like a challenge, and some help .. it would be appreciated! Thanks!
Hi @thebigguyy1 , You may have two problems. Have you checked the batteries in the remote, you didn’t say? Have you checked that the remote control is operating properly? This can be done by viewing the IR LED at the end of the remote that points at the TV through the LCD screen of a digital camera or mobile phone camera. Simply point the remote at the camera lens and press a button on the remote. When looking at the remote in the camera’s LCD screen you should see the IR LED light flashing. Try less used buttons first as the Power, Volume Up/Down and Channel Up/Down are the most used and can wear out through constant use. Regarding the TV black screen problem could you please elaborate on what you mean when you say “….picture will stay on for maybe 5 minutes and it goes dark. I can then try and turn the TV back on….” When the screen goes black does the TV turn off i.e. power light changes from on to standby or does the TV stay on, the audio is still on but no picture? If the latter try shining a torch at an angle close to the screen to check if there is an image there at all. It will be very faint if it is there. If there is an image detected then it is a backlight problem, which could be in the mainboard or the power board If there is no image then it could also be as above. You would have to remove the back cover and initially inspect the boards for anything obviously wrong such as heat stressed components or boards. After that checking the voltages on the power board would be the next step. if you can get hold of a service manual for the TV that would help as it would have the schematics for the boards. If you can’t find one (I couldn’t) then perhaps if you search online for the schematic by using the power board “board number” you may get lucky, i.e. search for (insert power board board number) schematic, as this sometimes gets results. Hopefully a start
