Vizio V0420E

[ned1]

Picked up 42 inch Vizio LCD from friend. At first when plugged in to power it will show orange vizio logo then when power on button pushed it change to white but black screen. Ordered power inverter combo board from Shop Jimmy. Got it pretty quick and this time the screen comes on, I have welcome Vizio logo on the screen then brightens will dim and it will go black again. It does it every time tv is turned on. I read on this website that bad bulb will cause it, strip it down all the way to backlight, 18 bulbs. Powered on all bulbs come on and appears 3 bulbs will stay brighter others will dim and again all die. Should I consider those bright bulb are problem or there is other test I can perform.

[Andrew F. Ali]

Re: Vizio V0420E

I am guessing here but I think the dim bulbs are the faulty ones so I'll wait to see what the real experts may say.

[ned1]

Re: Vizio V0420E

Thanks for reply. When I powered it on first time it stayed on longer then I tried to change input channel, (no remote) and I increased backlight level almost to 99 by pressing buttons on the side of tv.Maybe it has to do something with this, because after that it will shut off after 5 seconds when power on now.

[ned1]

Re: Vizio V0420E

Is there a way to check bulbs individual, bypass it with resistor on any other way. They are all short together on each side and resistance reading is 56.8 ohms from any left side end of bulb to any right side end of bulb.

[budm]

Re: Vizio V0420E

Can we see good clear pictures of the board and the lamp assembly, also the LCD panel model number so we can look up the spec to see how all the lamps are connected and what type of lamps they are?

[ned1]

Re: Vizio V0420E

I am having problems with pictures, maybe website problem. I will try again later. The board is combo power and inverter, bulbs are 3mm X 950mm. The panel is LC420WUG. I am powering backlight only with LCD panel removed, so maybe it should shut off after few seconds since T-con is not present. But all bulbs comes on.

[ned1]

Re: Vizio V0420E

Pictures are attached

[budm]

Re: Vizio V0420E

It should stay on without T-con board. So all the lamps light up evenly before shutting down since you indicate that 3 are lit up brightly? These lamps looks to be EEFL type and they are connected in parallel without having ballast caps per lamp like CCLF type.
http://www.beyondinfinite.com/lg-philips/lc420wug-sca1/

Those lamps are socketed, did you carefully try to reseat them?

[ned1]

Re: Vizio V0420E

I reseated all of them. After reseating it appears that all bright up evenly and shot down faster.

[ned1]

Re: Vizio V0420E

Can I bypass lamp to figure which one is problem.

[ned1]

Re: Vizio V0420E

If they are in parallel connection why would 1 lamp shut off entire backlight assembly. Can I insert one by one lamp to see when it starts to shut down?

[ned1]

Re: Vizio V0420E

Got it somehow to stay longer and took a picture. It appears that bulb #6 from the top is dim.

[stj]

Re: Vizio V0420E

interesting,
they are different colours.
i realise this is probably down to the camera sensor being more sensitive than the eye, but it shows they are either unevenly made, or pretty worn!

[ned1]

Re: Vizio V0420E

Where can I buy those bulbs?

[ned1]

Re: Vizio V0420E

STJ it was just camera, second picture may be better.

[ned1]

Re: Vizio V0420E

Maybe this picture is better

[ned1]

Re: Vizio V0420E

Can I replace eefl lamp with ccfl lamp?

[budm]

Re: Vizio V0420E

No.
Can you swap the #6 lamp with other lamp to see if the problem follows?

[ned1]

Re: Vizio V0420E

I swapped the bulb 6 and 1 and it was shutting down very fast. Then I completely removed bad bulb and the backlight stayed on, never shut off. So I definitely know which bulb is bad, now the question is where can I buy it in USA.

[budm]

Re: Vizio V0420E

A lot of people here use CCFL WAREHOUSE.
http://www.ccflwarehouse.com/?gclid=...FQaCMgod4msARg