Vizio E470VL got +5VSB, but no 12V

[Bugman1400]

EDITED: I thought my Vizio E470VL has +5VSB and no 12v on the PS board, but after plugging the cable back in and testing the pins on the Main board I realized that I do have 12V. I assume the 12V is turned on when the ON/OFF switch is pressed. The Vizio light in front does go from Standby Orange to White when ON. But, I still have no picture or sound. Test values of PS board are below.

+5VSB= +5.09
12V= +12.18
PS_ON= +2.25
I_ON/OFF= +3.27
LAMP= +3.18
DIM= +2.97

Any more testing I can do on Main board or is it just a replacement?

[dskall]

Re: Vizio E470VL got +5VSB, but no 12V

Do you get 12v going to t-con board?

[Bugman1400]

Re: Vizio E470VL got +5VSB, but no 12V

Do you get 12v going to t-con board?

What t-con board?

[dskall]

Re: Vizio E470VL got +5VSB, but no 12V

Do you have backlights?

[Bugman1400]

Re: Vizio E470VL got +5VSB, but no 12V

Do you have backlights?

Nope. Are those external to the two ribbon cables going to the LG display?

[dskall]

Re: Vizio E470VL got +5VSB, but no 12V

If we are to help you. I would suggest you familiarize yourself with how an LCD tv works. Lots of videos on youtube.

[Bugman1400]

Re: Vizio E470VL got +5VSB, but no 12V

If we are to help you. I would suggest you familiarize yourself with how an LCD tv works. Lots of videos on youtube.

This model doesn’t seem to have a separate t-con board and there are no backlights, picture (even when I do the flashlight test), or sound.

[neilc6]

Re: Vizio E470VL got +5VSB, but no 12V

You should include a picture of the entire back of the TV. Your model is an old LCD with CCFL backlighting and likely has a tcon hidden under a shield. A quick Google of your model shows a YouTube video from a guy that repaired his TV by cleaning the dust off his boards. I would also check the electrolytic caps on the power supply for bulging since they are common failures in LCD TVs.

[nomoresonys]

Re: Vizio E470VL got +5VSB, but no 12V

When it's in the "on state" very carefully check the voltage of the big capacitor, careful not to touch it with your hands, just the meter probes, should probably be around 400 volts or so, that voltage CAN KILL, don't do it if your not comfortable, next maybe check fuse/s on inverter boards, that's if they are separate and not built into powerboard, hard to tell without pictures.

[Bugman1400]

Re: Vizio E470VL got +5VSB, but no 12V

Followed Neil’s advice and decided to clean the board. I also decided to check the TV with the room lights dimmed and discovered that the CCFL backlight and menu screen come on when the ON/OFF is initially pressed ON. Sometimes it will last up to 15 seconds before it shuts off, but it seems to come alive every time. So, I think the CCFL is good and I think the Main board is good, but now my LAMP signal is at or near 0V. Before, it was reading +3.18V.

I wonder if I can disconnect the cable between the PS board and the Main board and just apply 3.2V to the LAMP pin of the PS board to see if the CCFL stays on. Which board supplies this signal?
What role does the DIM pin play on a CCFL TV? Which board supplies this signal?

[Bugman1400]

Re: Vizio E470VL got +5VSB, but no 12V

UPDATE: I bought a new PS board and replaced the old one only to find that the TV still had the same issue. After trying the flashlight test again, I discovered that I do see a menu screen in the background. So, assuming that both the PS board and the Main board are good, that leaves a defective CCFL. Anyway to fix a bad CCFL?

[nomoresonys]

Re: Vizio E470VL got +5VSB, but no 12V

need those pictures, help us help you.

[R_J]

Re: Vizio E470VL got +5VSB, but no 12V

You likely either have a bad ccfl or there is a problem on the connections on the distribution board inside the panel.

[Bugman1400]

Re: Vizio E470VL got +5VSB, but no 12V

You likely either have a bad ccfl or there is a problem on the connections on the distribution board inside the panel.

Bingo!

It took a bit of coaxing to separate the LCD from the backlights, but the damage is obvious. Not sure if I can just re-solder or need to replace the boards. Haven’t tested the CCFL tubes yet. Can the CCFLs be replaced? I checked out CCFLWarehouse.com, but all their CCFL replacements seem to have ends that require soldering.

[Bugman1400]

Re: Vizio E470VL got +5VSB, but no 12V

Looks like all the clips that hold the ccfls are too brittle and trash. Any place that sells these things?

[ajshoe]

Re: Vizio E470VL got +5VSB, but no 12V

best bet would be a tv recycler or Craigslist - might get lucky and find vizio ccfl set there. Id scrapped that set and go for a led or plasma 1080P set to repair.

[Bugman1400]

Re: Vizio E470VL got +5VSB, but no 12V

best bet would be a tv recycler or Craigslist - might get lucky and find vizio ccfl set there. Id scrapped that set and go for a led or plasma 1080P set to repair.

Too late for that now. More interested is completing the challenge. Think I got everything I need to complete the repair except the standoffs to hold the diffuser up.