Hi and thanks for taking the time to offer your assistance. I have a 3 y/o Vizio M420NV that was working a few nights ago and then would not turn on in the morning. The orange Vizio light is on, but will not turn white when the power button is pushed on the side of the TV or with the remote. I tried the system reset (unplug for a while, hold power button on TV x 30 sec, plug in) with no change.
I don't have any experience with circuit boards at the level I've been reading about on this forum, but I have picked up some basics from various posts and reading the stickies.
After reading a lot of posts and talking to Vizio's out-of-warrenty repair company, I concluded (without any real evidence to back it up) that either the power board or main board was the culprit. I opted to buy a new power board to see if that would be the easy fix. I installed it tonight with no change in my situation.
So, here's where I stand now….
I have a new power board installed. With the TV plugged in, I read 12V on pins 8-10 (on the power board at the connection coming from the main board) and 3V on pin 11…all other pins had no readings. With the power button held down and then after it was released, there was no change in voltage at pin 11 (which I understand to be the point where the main board tells the TV to turn everything on…in very simplistic terms).
I don't see any bulging caps on either board. I have an analogue multimeter and it's resistance selectors are either Rx10 or Rx1K. I tried testing the only thing I knew was a fuse on the power board (unplugged, selected Rx10) but saw no needle movement on either power board. I'm thinking, but not sure, that the 10x mag on the resistance is too much to be able to check the fuse.
That's all the data I have. I'll try to attach pics of the boards. Thanks again for any input you have.
I don't have any experience with circuit boards at the level I've been reading about on this forum, but I have picked up some basics from various posts and reading the stickies.
After reading a lot of posts and talking to Vizio's out-of-warrenty repair company, I concluded (without any real evidence to back it up) that either the power board or main board was the culprit. I opted to buy a new power board to see if that would be the easy fix. I installed it tonight with no change in my situation.
So, here's where I stand now….
I have a new power board installed. With the TV plugged in, I read 12V on pins 8-10 (on the power board at the connection coming from the main board) and 3V on pin 11…all other pins had no readings. With the power button held down and then after it was released, there was no change in voltage at pin 11 (which I understand to be the point where the main board tells the TV to turn everything on…in very simplistic terms).
I don't see any bulging caps on either board. I have an analogue multimeter and it's resistance selectors are either Rx10 or Rx1K. I tried testing the only thing I knew was a fuse on the power board (unplugged, selected Rx10) but saw no needle movement on either power board. I'm thinking, but not sure, that the 10x mag on the resistance is too much to be able to check the fuse.
That's all the data I have. I'll try to attach pics of the boards. Thanks again for any input you have.
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