Vizio HDTV20A

[jBusch]

Ok did some research and found a few articles that may have been solutions but did not seem to fit. If i missed my answer, sorry in advance.

I am John, here in Washington and I have this Vizio tv an employee brought in. We dont do tv work but thought I could look at it and save them some cash. I checked all the fuses and they test across. I have unplugged the power cords to the boards on the left and the right on the TV (see pictures) neither gave me any sort of image. I am told the tv gives sound for what we have displayed but no image. I can see the screen does not give off any light.

From the basic testing I have done and verifying that those chips on the side don't have burn holes in them I am guessing that its a PSU problem. I ran a volt meter to the two grey and black power connectors which go to both sides of the tv and tested for voltage only the black cabled provides any voltage all other have nothing shown on it. Oah and just for informational purposes I do have another employee who was a bit zealous and decided that with the TV plugged in to do some testing and rested his hand on the aluminum heatsinks on what i believe to be the PSU. The ones with the yellow shock stickers; well he did sustain a shock(I enjoyed that, figured I would share).

[retiredcaps]

Re: Vizio HDTV20A

Does the power LED come on? If yes, what color?

[cmj21973]

Re: Vizio HDTV20A

Go here to downloawn service manual (SM). It has troubleshooting flowcharts.

[jBusch]

Re: Vizio HDTV20A

Ok so yes the power light does come on. Several LED's turn on with one flashing on a smaller board under the main panel. I have an arrow pointing to that board on the image below. Flash back time here. When this TV first came in and I turned it on it had a slight burnt electronics smell that faded quickly. I thought well, older TV, might just be a small from something that went out. 10 min ago. I just plugged in the TV and started going through some trouble shooting steps. I smelt something burning, jumped up pulled the power cord and tried to find it. No luck. Called back Amanda (TV owner) we tried to smell the problem out. Ok no luck I plugged it back in and she saw some smoke. I jumped over to where she was an saw the area where it was coming from. That is also shown in the image below with the circle. As i was barley able to see the smoke its a general area. It did not appear to be coming from the capacitor. Now a bit more history which I neglected to mention. When the TV was initially having some issues before it came in I am told that there where jumping horizontal streaks of odd color. They would turn off the TV wait a few minutes turn it back on and there is was no more problem.

I do find it odd however that all of a sudden without any changes just looking that there would be something smoking. It can happen but,, that does not mean its not strange.

Other strange things to note there was no light from the screen when powered on and no OSD.

[cadiman]

Re: Vizio HDTV20A

The y drive and buffers are common failure on these. (on the left side of the tv)

Samsung panel with supporting boards.

The logic board in the center is a rare failure unless you were probing and let out the magic smoke.

You can normally hear the y and z,or x driver boards "running" as long as the power supply does not go into protect mode.

The board that isn`t running will be the failed board.

I would take a neon bulb tester and test for high voltage at the buffer test point.

You can touch one lead to the buffer test point and hold the other lead between your thumb and finger (you will be the ground) don`t worry you won`t get zapped. I do this all the time to check the y drive since that is the most common failure of all the plasma tvs.

If the bulb lights up then you have high voltage going to the buffers and the problem is most likely with the x,or z board on the right side of the tv.

You don`t want to use the tv ground because you are looking for high voltage (450volts)
and the panel ground may light the neon bulb at 50 volts.

[jBusch]

Re: Vizio HDTV20A

Sounds like a sweet party style test. Unfortunately I don't have a neon bulb tester. I was not probing and letting out the magic. I would take the credit for getting the jinn to come out of the bottle but it is simply not the case. I could probe the point and use me as a ground if you would be so kind as to indicate how to find this y voltage test point.

Now I thought with one of the drive boards out you would still get picture.

The unit does make noise when i plug it in and turn it on. Some hard clicks I can take some video to capture the audio if needed.

[jBusch]

Re: Vizio HDTV20A

bumping

So the easiest way to verify which thing(s) I need to replace would be?

[Gootch24]

Re: Vizio HDTV20A

Try this, being the bottom of the totem pole tester that I am Ive heard theres a simple method that you let tv run for ten minutes or so, then unplug and touch the heat sink on the x-sus and y-sus boards which ever one is cold to
the touch is failed, but I would guess, the Y usually the culprit in plasmas and I just replaced one ina vizio and have a LG same board tried correct me if Im wrong here guys,,good luck

[jBusch]

Re: Vizio HDTV20A

I do worry about that because as noted in the picture the board on the left with the circle does smoke when the tv is on.