Vizio VW42L FHDTV10A will not turn on without unplugging and plugging TV back in

[budm]

Re: Vizio VW42L FHDTV10A will not turn on without unplugging and plugging TV back in

budm, No, I didn't put the marks on there. I bought this TV brand new, so it must've been done at the factory.

I heated the main board up and the TV turned on and stayed on without any vertical lines. The only thing is now there is no sound at all. The vertical lines and the sound are related I'm sure.

I tested the output voltages and the regulators while nothing was working, except for the logo and the back light. Everything tested the same as stated in my findings from my original post except that it now has the 5.01v at pin B and 3.35v at pin A. I did notice that when I got the TV running the voltage at pin A varied quite a bit while a video was being played, 1.75v - 3.25v.

Next thing is to localize the heating area to help narrowing down the area.

[ken_taz]

Re: Vizio VW42L FHDTV10A will not turn on without unplugging and plugging TV back in

ce23 ce50 dont look good from here .. if they turn out bad change all same values on that board .
p.s where do the speakers plug in ? i am failing to see an audio chip .

Thanks petehall347, yeah the pictures don't show those caps very clearly. They look fine and are not bloated at all in real time.

I have attached a photo with the audio plug circled in yellow.

[ken_taz]

Re: Vizio VW42L FHDTV10A will not turn on without unplugging and plugging TV back in

Next thing is to localize the heating area to help narrowing down the area.

Thank you budm, I will work on that tomorrow and report my findings.

[nomoresonys]

Re: Vizio VW42L FHDTV10A will not turn on without unplugging and plugging TV back in

nomoresonys, you are talking about the main board, not the power board correct?

The main board, which I have pictured below, has a total of approx. 72 caps. on it.

The power board, in pictures two and three, has quite a few less than the main.

I agree, it would be a much easier job to have a meter to check these caps. instead of playing the guessing game. Lol

Ah ok, I see what you mean, I was looking at your first mainboard pic. it didn't show the whole board, that IS a shitload of electro. caps.

[dskall]

Re: Vizio VW42L FHDTV10A will not turn on without unplugging and plugging TV back in

I tested the output voltages and the regulators while nothing was working, except for the logo and the back light. Everything tested the same as stated in my findings from my original post except that it now has the 5.01v at pin B and 3.35v at pin A. I did notice that when I got the TV running the voltage at pin A varied quite a bit while a video was being played, 1.75v - 3.25v.

Not sure what pin a and b are. Voltages shouldn't be fluctuating

[nomoresonys]

Re: Vizio VW42L FHDTV10A will not turn on without unplugging and plugging TV back in

Hmmm, could be a bad voltage regulator.

[ken_taz]

Re: Vizio VW42L FHDTV10A will not turn on without unplugging and plugging TV back in

Hmmm, could be a bad voltage regulator.

Thanks nomoresonys. I've posted all of the regulator voltages from the main board in my original post. The voltages have remained the same and nobody has said anything about the voltages being off from what they should be.

[nomoresonys]

Re: Vizio VW42L FHDTV10A will not turn on without unplugging and plugging TV back in

Good question, wonder if U16 is correct, nothing on pin 2?

[ken_taz]

Re: Vizio VW42L FHDTV10A will not turn on without unplugging and plugging TV back in

Good question, wonder if U16 is correct, nothing on pin 2?

U16 is a 5v output regulator. The 2 pin is ground.

[budm]

Re: Vizio VW42L FHDTV10A will not turn on without unplugging and plugging TV back in

Post #1
U20
)11
1084
0739AL
Pin 1 = .55v
Pin 2 = 1.79v
Pin 3 = 3.32v
U19
)11
1084
0739AL
Pin 1 = 1.26v
Pin 2 = 2.52v
Pin 3 = 5.07v
U15
)11
1084
0739AL
Pin 1 = 2.09v
Pin 2 = 3.35v
Pin 3 = 5.07v
U22
AMC1117
F0748F
Pin 1 = 2.10v
Pin 2 = 3.36v
Pin 3 = 5.12v
U21
AMC1117
F0748F
Pin 1 = .00v
Pin 2 = 1.26v
Pin 3 = 2.51v
U17
AMC1117
F0748F
Pin 1 = 2.10v
Pin 2 = 3.37v
Pin 3 = 5.07
U44
J302
G9117
Pin 1 = 8.46v
Pin 2 = 9.72v
Pin 3 = 11.42
All those readings are correct, you can easily tell by subtract the output pin Voltage reading by the Adj pin reading, the result should be 1.25V +/- 3% (1.213 ~ 1.288V)

[ken_taz]

Re: Vizio VW42L FHDTV10A will not turn on without unplugging and plugging TV back in

Update on the sound not working. My bad, I had the sound cables plugged into the wrong ports for the component input. Sorry, the sound does work when the video is playing. I haven't track down which spot to heat to make the main board work properly yet.

[dskall]

Re: Vizio VW42L FHDTV10A will not turn on without unplugging and plugging TV back in

You did say in #19 that you had a varying voltage. Do you still have that?

[ken_taz]

Re: Vizio VW42L FHDTV10A will not turn on without unplugging and plugging TV back in

You did say in #19 that you had a varying voltage. Do you still have that?

Yes, pin A on the power board outputs. I think it has something to do with the back light. It is a constant 3.35v with just the power turned on and no video playing. With video playing the voltage varies from around 1.75v to 3.25v depending on the video.
When the back light wouldn't come on, I had a very low voltage at pin A .12v and pin B .03v. Pin B is a constant 5.01v regardless of operation when the back light is on.

[budm]

Re: Vizio VW42L FHDTV10A will not turn on without unplugging and plugging TV back in

If you look at the pin labels on the INVERTER board and trace it back to the power supply board pin A, B, C then you will know what each pin is. VIZIO usually uses Pin 'A' for BL-ON, and pin 'B' for 'DIM', most of the time pin 'C' is not used.
The power supply is used junction point for routing the control signal from the main board to the inverter board.

[ken_taz]

Re: Vizio VW42L FHDTV10A will not turn on without unplugging and plugging TV back in

Next thing is to localize the heating area to help narrowing down the area.

Ok budm. I didn't have much luck tracking down the area that needed to be heated yesterday. I heated a smaller area than the day before to start narrowing it down. The TV started up fine after the first heating, but I still wanted to narrow it down to a smaller area. I could not get the TV to malfunction again all day after letting it sit for hours at a time. It was a pretty warm day and I'm working in my garage without air conditioning, so I'm guessing that had something to do with it.

I went out first thing this morning while it was still cool out. Plugged the TV in and hit the power button. The logo turned white, the back light came on, but nothing else happened. The TV then shut off. I hit the power button again. Same thing, logo turned white, back light came on, only this time it did not shut off. It wouldn't shut off with the power button so I unplugged it to turn it off. I then placed a piece of cardboard along the line in the picture below, and lightly heated the corner of the board. I hit the power button and the TV came on normally, but shut off after like 15 seconds of being on. I hit the power button again and it powered on and stayed on this time.

As far as the pin "A" pin "B" thing goes, the only description or labels are on the wires which I am having a very hard time reading. I'm not real concerned with this right now. Thank you for your input on that issue.

[budm]

Re: Vizio VW42L FHDTV10A will not turn on without unplugging and plugging TV back in

You have 3 lytic caps in that section, try replacing them.
BTW, can we see the pictures of the whole back side of the TV showing how all the boards are connected together? I cannot tell what that white connector go to what board.

[ken_taz]

Re: Vizio VW42L FHDTV10A will not turn on without unplugging and plugging TV back in

You have 3 lytic caps in that section, try replacing them.
BTW, can we see the pictures of the whole back side of the TV showing how all the boards are connected together? I cannot tell what that white connector go to what board.

Ok budm, no problem. It goes to the manual control panel. I will work on replacing those caps. Thank you!

[budm]

Re: Vizio VW42L FHDTV10A will not turn on without unplugging and plugging TV back in

BTW, for pin point heating of the lytics cap, sometime I use 25W iron on the top of the suspected cap to heat it up for about 15 ~ 25 seconds then plug in and see if the symptom will go away or not.

[ken_taz]

Re: Vizio VW42L FHDTV10A will not turn on without unplugging and plugging TV back in

Good idea. I was trying to think of a way to pinpoint it even better without ruining the cap in the process. Hair dryers are a good starting point but when it comes to really heating a tiny area....not so much. Thanks!

[R_J]

Re: Vizio VW42L FHDTV10A will not turn on without unplugging and plugging TV back in

This manual has similar parts in that area, on page 164 are the transistors U43 (page 160) is vga control ic. Looks like your problem could be associated with OPCTRL (4 or 5) lines