Facing TV Problems? Ask a TV Technician.
Hello and sorry you're having problems. You were on the right track by replacing the HDMI cables, since the message is either caused by an intermittent cable/signal, or a fault on the Mainboard. The Mainboard processes all external Inputs on the set and it's EEPROM (processor) starting to fail can cause this problem. Just to make sure we're on the right track, do you have more than one "Source" connected to the TV, and does the same issue occur regardless of what source you select? Additionally, are you looking to repair the set yourself?
If you've ruled this out by replacing cables, and also trying to leave simply one source connected at a time ( to rule out an intermittent signal from the source DVD cable box, etc.), then you need to replace the Mainboard in your TV which is at the link below for purchase and will fix the issue. it's plug and play- meaning no soldering or special tools are needed to replace it. You must remove the rear of the set to access it however. The board is available at the link below:
Alternatively if you have this repaired at a shop, you're typically looking at between $450-$500 parts and labor and a shop can be located at the link below:
If you need further assistance let me know. Please do not forget to click the 5 STAR RATING, at the top of the page for my efforts. It is my livelihood and you can follow up at any time if needed.
Do you need any further assistance with this?