Re: Vizio VW42lfhdtv10a - No standby

Thanks budm. I read the basic troubleshooting. The power board troubleshooting does apply. I measured the PS_ON output voltage with the TV on at 1.93v...does this sound like the correct voltage, or could it be just enough to get things going? (You quoted 3.3-5v in the tutorial).

I measured everything I could coming off the mainboard - and all looks normal to me except U21. Problem is, I have no idea what u21 is supposed to do.

I keep circling back to why this problem would be intermittent (and slightly noisy), unless...

Re: Vizio VW42lfhdtv10a - No standby

Interesting idea - I'll give it a shot.

Is there a feedback circuit that would require the mainboard to be plugged in for the power board to output the voltages?

Re: Vizio VW42lfhdtv10a - No standby

Ah - excellent question. I did check the voltages at the power board output in [B]ON[/B], [B]OFF[/B], and [B]FAIL [/B]modes. The [B]ON [/B]voltages are listed in my first post, but I didn't list the others.

In the [B]OFF [/B]mode (w/ orange light), there are a few mV on some of the pins.
In the [B]FAIL [/B]mode, there is [B]0v [/B]on all the pins. It's as if the main fuse blew - but I checked it, and the TV comes back on (I also replaced it anyway).

I should also note that this seems to be an intermittent problem....

[I]First post, so please be gentle [/I]

I have a 42" Vizio LCD that doesn't consistently go into standby when you turn it "off". It usually goes from white light to [I]no [/I]light (no orange light). In order to get the orange light working again, I have to unplug it for a few seconds and plug it back in. (EDIT: To be clear, the TV turns on and works normally when you reset it and have the orange light on).

I took it apart to do some investigating (thanks badcaps!), and found the power board to have a very light humming/buzzing sound when the set...

Re: New Members - please post your introductions here

Hi there! Computer Engineer here...but like many engineers, I don't actually have the luxury of working in the field I studied in! I enjoy tinkering in low-pressure situations (like, uh, fixing my broken TV).

Re: Vizio VL470M "No Power"

Did you unplug and re-plug the set? I've been having a similar (?) problem in which I turn off the tv and it doesn't go into standby (orange light off). I can get the tv to turn back on if I just unplug and plug back in after a few seconds.