Vizio VO420E Black Screen, HELP!

[LBradford0007]

While watching my Vizio VO420E last week, the screen went black on me. I still have Audio, and the Vizio logo goes from Amber to White when turned on, but the screen is pitch black. I was originally told it was the Power Supply over the phone by Vizio. I purchased a new Power Supply (Model # 0500-0412-0750) and put it in yesterday. When I turned the TV back on, I had a picture for about 5 seconds before the screen went black again, so I'm assuming the Power Supply was not the problem. I have done some research and a few people have told me it is the Backlight Inverter, but upon further inspection I've read that this Model does not have a Backlight Inverter, so I'm at a loss. I have a Dish Network Receiver & Playstation 3 hooked up via HDMI cables. Thanks in advance for any help, I'm clueless right now...

[LBradford0007]

Re: Vizio VO420E Black Screen, HELP!

Just wanted to give an update. I just took the cover back off and tried again, it did the same thing as noted in my original post. I did notice that after turning the power on, I heard a click from the Power Supply, followed by a bright blue LED that only stayed on for 3-4 seconds before going off.

[tom66]

Re: Vizio VO420E Black Screen, HELP!

Can you post some pictures of inside of your TV?

It is possible you had bad CCFL (fluorescent) tube if this does not use discrete inverter and drives all the tubes from the power supply. Would be rare for a Vizio though.

[LBradford0007]

Re: Vizio VO420E Black Screen, HELP!

Sorry if the picture isn't great, had to use my phone. The board on the left is the one I replaced Friday to no avail.

[budm]

Re: Vizio VO420E Black Screen, HELP!

You have power supply-inverter combo board, so, like TOM said, you may have lamps problem.

[LBradford0007]

Re: Vizio VO420E Black Screen, HELP!

Thanks guys. Where exactly are the lamps located? And how could I check to see if they've gone bad? I called the only local repair place we have around here after putting the new board in, they gave me a flat rate of $ 328 to fix the TV so I'm really hoping to get this thing fixed myself, otherwise I'd be better off just purchasing a new TV.

[tom66]

Re: Vizio VO420E Black Screen, HELP!

The lamps are physically inside the LCD panel. This video shows the replacement inside a Sony, but the procedure is similar for any TV.
https://www.youtube.com/watch?v=8oZn...=results_video

[LBradford0007]

Re: Vizio VO420E Black Screen, HELP!

I found this picture while searching on here earlier. This looks identical to my old Power Supply, it had burn marks in the same spot, so I replaced the Power Supply but the new one is doing the same thing, but it isn't burnt up. This is a picture I stole from another thread on here, but as I said, the Power Supply I removed from my TV Friday looks identical to this one, burn marks and all. This poster said he had the same problem as I am having, so he just replaced the caps for the CCFL and his worked perfectly, I replaced the entire board so why isn't mine working?

[budm]

Re: Vizio VO420E Black Screen, HELP!

That bad ballast blue cap burnt up can make 2-second to black, bad lamp can also cause 2-second to black. You can have the same symptom caused by more than one type of component failure.

[drpj23]

Re: Vizio VO420E Black Screen, HELP!

Did you check the CCFLs?

[LBradford0007]

Re: Vizio VO420E Black Screen, HELP!

I haven't been able to check the CCFL's yet, I'm currently at work. I will check them in the morning. It sounds like thats what it is considering I changed the board and it's still doing the same thing. Will I be able to tell immediatly which ones are burnt out or is there a certain way to check them? If it does end up being the CCFL's, where would one go about getting replacements as I haven't been able to find them through the minimal research I've done on them tonight.

[budm]

Re: Vizio VO420E Black Screen, HELP!

http://www.ccflwarehouse.com/ this where most people here get them. Just be real careful when you remove that LCD panel from the frame assembly, VERY easy to break it.