Another VIZIO turns off randomly
I have a VIZIO 42" LED TV, model E422AR, about 3 yrs old (out of warranty). The TV is wall mounted in my bedroom. A few months ago it started randomly 'turning itself off'. By random I mean it might not happen for a few days, then happen several times in the course of a minute. The usual pattern is it happens a few times each evening.
When it happens, there is no picture or sound, the same as if I had manually turned off the TV via the remote, but with one exception: the VIZIO logo on the bezel beneath the screen remains lit, and is 'brighter' than it is normally when the TV is on. Other than the brightly lit logo, the TV appears to be in its normal off/standby state. In fact, if I then press the power button on the remote, the TV turns back on and all is well again (picture and sound) until the next time it decides to randomly turn itself off again.
After doing some hunting around online, I found many other VIZIO customers complaining of similar symptoms, although in most of those cases I the TV either failed completely (wouldn't turn back on), or the user had to unplug the TV, wait 10 or 15 secs, then plug it back in to get the TV working again (I've never had to do that). And no one described their TV's logo as still being lit when the TV failed.
Since most of the failed cases I read about turned out to be a bad power supply board, I went ahead and purchased one online. It was an exact match to mine, right down to the board's manufacturer, part number and rev letter. I went ahead and swapped the boards, powered the TV back on, and within a couple of minutes it failed again with exactly the same symptoms. %#*@.
So at this point I can safely assume that either the problem is *not* the power supply board, or the replacement power supply board I bought online has exactly the same problem as mine (certainly a possibility; I'm sure the board I purchased was used).
I have a hunch that the TV's hardware is ok, that this is some sort of glitch in the firmware. I can imagine there are points in the code where the default action in response to some error condition is to put the TV into the exact same state I'm seeing now. I could test out that theory by reverting back to an earlier firmware level and see if the problem disappears or the symptoms change, but it appears VIZIO offers no way to do that -- not only is there nothing in the TV's menus for loading firmware, but there are no firmware downloads offered on VIZIO's own support site.
I have no service manual or schematics for the TV, so I'm pretty much stuck at the moment.
The problem of course is that I have no way to capture the TV's state at the instant it fails. So checking voltage levels after unplugging the TV and plugging it back in will likely be futile, unless a component is 'on the edge' or out of spec. I could try operating the TV with its back off and, after it fails, leave it plugged in and measure voltages then, but that would be hard to do as the TV is still in daily use.
Because the TV is still in use, any 'try this, try that' type troubleshooting will be painful, as it would mean pulling the TV off the wall, removing the 10,000 screws from the back, testing whatever new steps are suggested, then, short of coming up with an actual fix, reassembling it and remounting it on the wall. So I'm hoping I can get a bit closer to the source of this problem without having to continually open up the TV.
Is this a good question?