Originally Posted by CleCakYngMfd
Uh-Oh. Appears to be a dead Power Supply. Unplug all devices from the TV.
You can try to unplug it, Press-n-Hold the Power button on back for 20 seconds. Leave unplugged for 12+ hours. Plug in. Try to power it up. If no go, wait another 24+ hours with it plugged-in before powering-up. See if that works. You can repeat and lengthen these procedures a few more times, if you're patient.
If it does now work, it's only temporarily. You can leave it on 24/7 until it dies. Either way, it needs service or replaced. (You could risk and buy a PS board, or better yet, purchase and replace all the boards at the same time. If just replacing the PS board - and the problem is another board - there's a risk of messing-up the new PS board.)
Hey, had a question because it was ignored when I brought it up before. Here are the symptoms and I'm wondering if you could point me to a better narrowing down of what is needed:
1) Turned off the TV to wash the display. Standard just lightly damp rag, etc.
2) Turned on, backlight was active, about a 20 or 30% gray on the display. No text or image with it. Turned off the display.
3) Turned it on, this time backlight active but pure black on the display. It matched the symptoms of others here, with the power light coming on, then going off, nothing displayed.
4) After fussing with it, I unplugged the set for 24 hours and drained the caps for the PS board.
5) After doing this, the screen turned on and went to the V logo splash screen, but went into a boot loop.
Now, I have a suspicion that I turned the set on during the firmware update and a bad flash occurred to the bios chip on the mainboard (hence that gray screen described in number 2 above). Due to me interrupting the process, then fussing with turning it off during a potential update after powering it on during such a thing would corrupt the firmware without a doubt (that is computer tech thing, so sure on that).
Another possibility comes up with me unplugging the set for 24 hours and draining the caps. On older models than this, the caps would not discharge and would hold a state and cause the screen to remain black, from my research and if I'm remembering those pages correctly. They recommended to unplug for an extended period of time and holding the power button for excessive time while unplugged to fully discharge. This would point to a potential PS issue. But, it could have also just been transient and arose at the same time as the other issue. Otherwise, this points to the PS needing replaced.
The bad flash refers to needing a new mainboard, if I am correct, or desoldering the bios chip, using an eeprom programmer to load a fresh rom image onto the bios chip, then resoldering the chip to the board.
So my question comes in whether Vizio implements a safety dual bios to reload a firmware in the event of a bad flash, or have another way to load a firmware in the event of a bad flash and whether this description on how to factory reset the TV could also cause it to look for a fresh bios on, say, a USB drive plugged into the non-USB 3.0 port on the device, or if you think the factory reset may resolve the boot loop issue?
Considering the instructions on how to do the factory reset, I figured I would ask.
I have the P50-C1 LTMWTNAS serial variant.
BTW, Vizio, if you frequent this thread, ADD A SECOND BIOS CHIP TO PREVENT BAD FLASH ISSUES! Either that or implement a safety reflash for the TVs similar to what modern MBs for PCs implement! Then just give us access to the firmware in like an FTP so we can select the firmware version we like in the event of issues with a newer firmware. Users will come to a consensus on which firmware works best for them!