Chosen Solution
I recently purchased a cheap Vizio 4K led tv in the hope of fixing it. The model is a M55-C2 and the previous owner had it for one year mounted on his wall. The power light turns on and it will either flicker the Vizio symbol for a 1/4 second or be blank when turned on. When I say blank I mean a extremely dim/blueish version of what’s on the screen. Here’s a really interesting part. I can hold the mute button to turn the backlights and panel off (audio only mode) and once I do I lose the dim/bluish picture and just I get a black screen. I then hold the back button to get out of that mode and I get a clear, perfect picture of what’s being played for half a second. It then immediately goes back being dim. I can also get a picture for half a second by unplugging the LVDS cable and then plugging it back in. The sound works perfectly and all the backlights work (removed panel to take a look). All the voltages coming out of the power board seem normal. I called 5 tv repair places and told them my situation and they had varying answers. They said it could be the t-con, bad panel, mainboard, or the backlights. I replaced the t-con, LVDS cable (t-con to main), and currently have another mainboard coming in the mail from Jimmy. They sent me the wrong board in the right box last week. I’m having a lot fun playing with this project but would like to see some progress. The biggest fear is that it’s the panel but I don’t know how it could be if I get a clear picture for half a second. It almost feels like the panel isn’t getting the power it needs. Any help would be much appreciated.
@answerorhelp that is a tough one but it does sound like an issue with the main board since you are getting the backlight. Now you do want to check the voltages to the main board from the powerboard. The required voltages should be marked on the board. If your power board does not supply that, your main board can not generate the picture. I guess right now it’s best to continue the way you are progressing. Once you got the new main board let us know what you get.
I had the exact same problem! The TV will turn on (power LED on and backlight turns on), but no picture appears. The sound will work through the inputs. The remote is able to turn the TV off and on. The mute-hold trick to turn the backlight off also works, followed by the back-hold trick to turn the backlight on. I ordered a replacement T-Con board, power supply board, LED driver board, and main board for my Vizio M55-C2 via ShopJimmy. I swapped out components one-by-one, and it turns out that the power supply board was to blame. I didn’t check which voltage rails were suspect on the board, but it’s clear that the power supply was partially working. (ShopJimmy shipped a broken/incompatible main board, so that made my troubleshooting more difficult.) Replacing the power supply board with a new one fixed everything. Hope this helps someone in the future!
