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

[ken_taz]

Summary
======
Vizio VW42L FHDTV10A will not power on without unplugging and re-plugging the TV back in several times.

Problem
======
The TV will not always act the same way when it is plugged in to try and get it to start up.

First, I plug the TV in and get the Vizio logo to light up orange. Press the button to turn it on and nothing happens.

I then unplug the TV and wait a few seconds and re-plug it back in. This time when I press the button, the Vizio logo turns white, but no back light comes on. During this time the outputs from the power board are as follows:
[U]Outputs going to inverter board[U]
24v = 24.9v
SGND = .003v
A = .12v
B = .03v
Outputs going to main board
PSON = 3.18v
12v = 11.5v
SGND = .001v
5v = 5.17v
A = .12v
B = .03v

I then unplug the TV for a few seconds and re-plug it in again. This time when I press the button the logo turns white and the back light comes on. I also cannot turn the TV off when just the logo and backlight come on.During this time the only significant changes on the outputs are the A and B outputs.
A = 3.34v
B = 5.01v

I can sometimes get the TV to come on and function properly. I've left it on for a few weeks at a time so as not to have to try and get it to turn on again, lol.

Things Tested
=========
1 - The filter cap. on the PSU showed a voltage of just over 350v.
2 - I could not find any visual evidence of bad caps throughout the whole system.
3 - All fuses tested good. 1 on T-con, 1 on inverter, 2 on main.
4 - I checked the voltages of the regulators on the main board.
Main board regulators

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
U16
AZ7805T
-E1
748J13
Pin 1 = 11.41v
Pin 2 = .00v
Pin 3 = 5.01v

I have read many threads of different issues with Vizio TV's. I am looking for ideas on where and what to check. I am not an electrical Wiz, but do know enough to be dangerous, lol. If this TV isn't worth the time or money to repair I'll be bummed because the picture is, or was, very nice. I'm hoping to save it for in my bedroom to replace the 14" tabletop there now.

I have attached pictures of the 4 boards.

Thank you in advance for your help!

[budm]

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

When not working the BL-ON is not present, LED did not change from Amber to white.
May be EEPROM problem:
http://www.shopjimmy.com/vizio-vw42l...eprom-only.htm

[Andrew F. Ali]

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

may be eeprom problem:
http://www.shopjimmy.com/vizio-vw42l...eprom-only.htm

+10

[ken_taz]

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

+10

What do you mean by +10, Andrew?

[ken_taz]

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

When not working the BL-ON is not present, LED did not change from Amber to white.
May be EEPROM problem

Thanks for your reply, budm. So you're saying that the EEPROM could be the cause of it not turning on at all one time, and then turning on after multiple times of unplugging and re-plugging it back in, or just that it caused the TV to not turn on at all?

[budm]

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

Yes, but look real close at your main board P/N to make sure the EEPROM is made for that main board P/N and version.

[Andrew F. Ali]

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

+10....means....I totally agree with the previous post.

[R_J]

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

Try replacing CE13 & CE17, 470uf 25 volt on main board

[budm]

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

Try replacing CE13 & CE17, 470uf 25 volt on main board

Good eyes! it looks like one of them has slightly bulging top.

[ken_taz]

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

Try replacing CE13 & CE17, 470uf 25 volt on main board

Thank you R_J. I will replace those before I replace the EEPROM to see if that takes care of things. Wow, such a slight bulge on CE17 I never even noticed it. I tested both with my ohm meter and they did not respond. I will reply when I get them changed out.

[ken_taz]

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

Try replacing CE13 & CE17, 470uf 25 volt on main board

I replaced both CE13 and CE17 caps with 470uf 35v caps from my local Radio Shack. Thank you for spotting the tiny bulge in the one cap and knowing that the problem could lie in the two that you directed me to, R_J.

The TV fired right up and seems to be working fine. I haven't hooked up a video source yet, but I can switch to all inputs with the remote and it shows up on screen.

Thank you everyone!

[ken_taz]

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

Well, I finally got around to hooking an old DVD player up that I had stored in my attic. I turned the TV on and switched it to the component input that the DVD was hooked up to. I ran into the house for a DVD and when I returned, the TV had turned off. I turned the TV back on after loading the DVD in the player. I had a picture for a few seconds and then it started making a loud buzzing noise thru the speakers and the picture had vertical lines across the whole screen. The TV then shut off after a few more seconds. I was able to turn the TV back on and go thru the same process again repeatedly. Oh well, I guess the caps weren't the only problem.

[nomoresonys]

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

Wouldn't be surprised if you have one or more bad caps on your powerboard still.

[angelos]

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

I agree, change all the electrolytics on the main board.

[ken_taz]

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

Wouldn't be surprised if you have one or more bad caps on your powerboard still.

I agree, change all the electrolytics on the main board.

The power board and the main board are two different boards.

Change out all the caps on the main board? Do you have any idea how many there are on the main board?

[budm]

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

BTW, I noticed that some of the those caps have black marking on the top. Did you do that or someone else worked on the set before you?
Did you try heating up the main board with hair dryer for a few minutes to see if the TV will come on normally?
Did you check the DC Voltage of the power supply outputs and the Voltages of the regulator ICs again when it is not working?

[nomoresonys]

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

The power board and the main board are two different boards.

Change out all the caps on the main board? Do you have any idea how many there are on the main board?

Looks like about `15 or 16. This is where a meter that can check capacitance is handy, otherwise it's a guessing game as to their operability.

[ken_taz]

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

Looks like about `15 or 16. This is where a meter that can check capacitance is handy, otherwise it's a guessing game as to their operability.

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

[ken_taz]

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

BTW, I noticed that some of the those caps have black marking on the top. Did you do that or someone else worked on the set before you?
Did you try heating up the main board with hair dryer for a few minutes to see if the TV will come on normally?
Did you check the DC Voltage of the power supply outputs and the Voltages of the regulator ICs again when it is not working?

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.

[petehall347]

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 .