H49M3000 Sometimes no video?

[Usamahbanana]

Hi everyone

Okay, I'm kind of new to all this, so it's very possible that I missed something basic, but I'm feeling quite stumped right now. I've had this Hisense H49M3000 for around 4 years, and it only recently developed the issue of having sound, but no video.

I've replaced both the main board and the power board to no avail. I discovered just today, that it only sometimes decides to not display video; when pressing the power button, there seems to be around a 10% chance of there being no video. When there is video, it can last a few hours before the video swiftly fades.

I don't think anything is overheating, because I let it run for a few hours until the video went, turned off the TV, then immediately turned it back on, for there to be video. I've also done a simple backlight check of putting a torch up to the screen, so if that's anything to go by, I can confirm that it's not the backlight.

Also, there are couple of horizontal lines going across the screen, but that might be unrelated.

Any help would be appreciated

Thank you

 

[Usamahbanana]

After further inspection, I think I've whittled down the options to the t-con board, and the cof(?) board. The thing is, it looks like the ribbon cables are not the removable kind; they appear to be glued/bonded to these boards. If anyone has any solution to this I would be grateful.