Chosen Solution
One day when I changed my input from an HDMI port to the Smartcast app/screen on my TV, the screen started turning off and back on (with 3 wide vertical bands in a gradient from dark to light at the center of each band horizontally across the screen) until it became completely black. It takes about 5-10 seconds and 4/5 flashes for the cycle to end. At the time I figured it was just a glitch in the Smartcast app, a bad ad loading that caused a crash or something. I hit the power button on the remote and nothing happened. So I unplugged the TV, plugged it back in, and hit power on the remote again. The Vizio logo came up, normal looking and properly bright. My TV tried to load the last input it was on, the Smartcast app, and the off/on cycle with the screen happened again until the screen went dark. Luckily I have CEC enabled, and after I unplugged the power again I was able to get the screen on with my Nintendo switch. The TV turned on without issue. Out of curiosity I switched to the Smartcast app again. Off/on cycle repeated with the same result. Once I got the TV back on with the switch, I reset the TV to factory settings. Then everything worked again for a while. Smartcast was fine, all HDMI was fine. But within a day, Smartcast caused the issue again. So I decided just don’t use smartcast and I should be fine. A few days later with my switch, PC, and PS4, the TV decided to go black on me within 30 minutes to an hour of use. No flickering, just off. Sound continued to play though. I decided it is probably best to not use it and unplugged it, and moved my bedroom TV out to the living room as a replacement. As I moved the Vizio out of the living room, I noticed it was running pretty hot on the back, at least by the HDMI inputs, and had a hot plastic smell. I contacted Vizio and was told the repair costs so much it would be worth it to just buy a new TV. Seeing as I spent $1500 on it and it’s only been about 3/4 years, I was pretty unhappy with that response. Today I finally took the time to take the back off the panel and see if anything wrong was noticeable, but nothing looks burnt or out of place. I went through the procedure of getting it to crash and found some advice online about checking with a flashlight to see if just the backlights were out. Sure enough I could see a faint picture with my phone light shining on the screen after it went completely dark on me. I also noticed that the power and t-con boards were buzzing, which I think is normal. What was abnormal to me is that when the backlights were flashing from off to on, the power board was making a really loud extreme buzz, like crackling electricity. I turned off all the lights to look for arcing of some kind but couldn’t see anything. I also did not notice any dust that had collected inside the panel and there was no intense heat from the components. The heat may be normal and with the back cover off the TV could cool quicker. Sorry for the long story but I wanted to detail all of the troubleshooting I have taken. My guess is if I can find some replacement boards for the unit I could just repair it myself. The problem is I really have no clue what to replace. My gut says the power board because that’s where the most intense abnormal buzzing was coming from as the issue occurred. But again I have no idea, and I assume a power board issue means other components could also have been damaged, so I figured I’d ask here. Any advice is welcome, thank you!
Connor MacDonald Vizio uses a hodge podge of parts and does not always have the quality that we may expect. They do have issues with improperly soldered connectors. So, check on that. Make sure that all connectors are properly connected and cables properly seated. A quick resoldering of the connectors may also help. Since the backlight flickers etc. it is most likely that the backlight strips are failing. Again, not uncommon for Vizio. You can replace those by disassembling the panel. Not terribly complicated just a bit of a PITA due to the size of the screen. Post some good pictures of all of your boards with your QUESTION. That way we can see what you see. Adding images to an existing question - iFixit Repair Guide
