Sony 75x8500c tv turns off & 6 blinks

hello
One device was Sony model 75x8500c with 6 blinks.
I changed the backlight. It was fixed. But after an hour it turns off again and flashes 6 times and I have to turn it on again. I tested the backlight and it was fine.
There is no problem with the connections. You had the same problem.
Thank you for your help.