Vizio V042L No Picture has backlights.

[landyboy]

Re: Vizio V042L No Picture has backlights.

Ok with 1 and 8 jumpered I get a blue screen with menu and the TCON power LED is now on.

[tom66]

Re: Vizio V042L No Picture has backlights.

Great. Any bad effects noticed from doing this? If not I'd just leave the jumper in place.

[landyboy]

Re: Vizio V042L No Picture has backlights.

No It seems to work Fine. I will just place a perm jumper. Does this indicate that the fet is bad?

[tom66]

Re: Vizio V042L No Picture has backlights.

I think so, it probably has a source-gate short, which is reasonably common with FETs.

[budm]

Re: Vizio V042L No Picture has backlights.

The T-CON gets turn off to safe power when TV is OFF, otherwise it will use about 10~15 Watts of power, but if it runs from 12v/24v switched power supply then it will not be drawing any power when TV is off

[philliesfan30m]

Re: Vizio V042L No Picture has backlights.

i know this problem was solved but i didn't want to open a new thread because i am having the same problem except that i don't have a reading on u44 and i'm not get power to the inverter board i'm getting power to the main video board but not to the inverter board and no power seems to be coming from the psu to be able to go to the inverter board thanks in advance for any help

[budm]

Re: Vizio V042L No Picture has backlights.

You will not get the voltage to U44 untill the 12v/24v power supply is turn on by the main board. So right now the main board may not be sending the PS_ON to the power supply board or the 12v/24v POWER SUPPLY or the PFC Voltage booster is not working. Pictures of YOUR power supply board? The rest of the regulators on the main board checked out OK?

[philliesfan30m]

Re: Vizio V042L No Picture has backlights.

yeah all the regulators checked out almost exactly as to the reading the person who started the thread has. here are some pics of the boards. what do i need to start checking next? i was reading other threads and they were all saying the inverter board was bad. cause the 2 mosfets i checked read 0 and the other 2 read 10k and they were saying they should read 8.5k i think. the orange vizio light turns to white but i don't have anything on the screen no backlight that i can tell i used the flashlight thing and i couldn't see any pic at all. that is why i have so many pics of the inverter board cause they say the 1 ic goes bad causing the mosfets to go bad from what i read. could the caps be bad also? sorry 1 thing at a time lol thanks in advance for any help

[manstoblame]

Re: Vizio V042L No Picture has backlights.

Here's a dumb Idea clean or replace the cables going to the T-Con board and see if that helps

[budm]

Re: Vizio V042L No Picture has backlights.

Since you are not getting the 12v/24v at the power supply output, you need to find out if you are getting PS_ON signal to turn on the power supply or not, there are labels at the the connector, look for PS_ON, it should have around 3vDC. You need to verify if the power supply is working or not. You can disconnect the power cable to the Inverter board to see if the 24v will present.
This model is known for having blown Inverter board.
http://s807.photobucket.com/user/bud...?sort=3&page=1

[philliesfan30m]

Re: Vizio V042L No Picture has backlights.

ok the tv is plugged in and i checked the pson and it has 0 volts i also checked everything else and the only place i have volts is at the 5 volt standby which i have a little over 5 volts on all 3 connectors but nothing anywhere else

[budm]

Re: Vizio V042L No Picture has backlights.

So it means the main board is the problem right now, you can disconnect just that PS_ON connection that goes back to the main board and use 1K resistor between the 5V and the PS_ON pin of the power supply to force on the 12/24v section.

[philliesfan30m]

Re: Vizio V042L No Picture has backlights.

ok i did that and have 12 and 24 volts now what do i need to check?

[tom66]

Re: Vizio V042L No Picture has backlights.

This indicates the main board is bad.
If you get a second 1k from 5V to BL ON (maybe labelled as "A" or "B", try both) and backlight comes on, you know only fault is with main board.

[philliesfan30m]

Re: Vizio V042L No Picture has backlights.

it has an a-b and c on it so if i run a 1k resistor between the 5 volt standby to where the a-b or c goes into the inverter board then the backlight should come on? and is the main board fixable or not?

[budm]

Re: Vizio V042L No Picture has backlights.

You know, just to be sure, report YOUR regulators voltage readings for us to see.

[philliesfan30m]

Re: Vizio V042L No Picture has backlights.

ok i will do that in a few seconds but does it matter what is hooked up? do u want me to plug back in all the connectors or doesn't it matter?

[philliesfan30m]

Re: Vizio V042L No Picture has backlights.

here are the regulator readings with the tv on and the white vizio light on and the connector connected to the psu and main board but not to the inverter board and the t-con light comes on for a few seconds then fades off

u15 -1.24, 0, +1.70
u16 +11.04 0, +5.05
u17 -1.23 0, +1.72
u19 -1.24 0, +2.55
u20 -1.25 0, +1.49
u21 -1.23 0, +1.25
u22 -1.23 0, +1.78
u44 -1.24 0, +1.43


they aren't even close to what the original poster had. what else do i need to check out?

[philliesfan30m]

Re: Vizio V042L No Picture has backlights.

and the t-con light only comes on if the connector to the inverter board is disconnected then it comes on for a few seconds when you turn the tv on but if the connector is disconnected and you turn the tv on then the blue light on the t-con board never comes on at all if that matters.

[budm]

Re: Vizio V042L No Picture has backlights.

So how do I read the list voltage on the list?
For example on U21:
u21 -1.23 0, +1.25
How do count the pins?
One pin is Minus 1.23v, second pin is 0V, third pin is 1.25V?
Can you also put down the no. as printed on the body? Those with Minus number sure cannot be right.
Please report the reading in the format as shown in this thread:
https://www.badcaps.net/forum/showth...999#post300999
If you look at the regulator (1117 series) with the big tab up, left pin is the pin1, middle pin is pin 2 which is also tied internally to the big tab), right pin is pin 3.
U16 is not 1117 series, it is just the 5V regulator.