Vizio VA26LHDTV10T

[CraigR]

Vizio VA26LHDTV10T When plugged in the logo is white and when the power button is pushed the logo turns orange and stays that way. I get no picture or sound. I checked the voltages at the connector and I am not getting the 24v or the 12v as stated next to the connector but I do have the 5v and 5v at the PS_ON just not sure what my next step should be.

[budm]

Re: Vizio VA26LHDTV10T

What DC voltage (measure right at the two legs of the cap) do you get at the main filter cap (450VDC cap laying on its side) when PS_ON is present?
Can I see the pictures of all the boards? There is a board with Brown/Blue wires connected to it, like to know what that board is.

[CraigR]

Re: Vizio VA26LHDTV10T

Here is the other board. I will check voltage also.

[CraigR]

Re: Vizio VA26LHDTV10T

I also get 393.1 volts at the cap.

[budm]

Re: Vizio VA26LHDTV10T

OK, so the PFC Voltage booster is OK, you need to inspect the 12V, 24V SMPS section next. Post the picture of the bottom side of the power supply board, then look at the area of the 12V/24V section.

[CraigR]

Re: Vizio VA26LHDTV10T

Here is the bottom.

[CraigR]

Re: Vizio VA26LHDTV10T

Just pulled out of circuit and checked the diode the cap and the mosfet it the 12/24 volt section you marked and all good.

[budm]

Re: Vizio VA26LHDTV10T

OK, there is a SMD 8-PIN SMPS IC that drives the MOSFET for the 12V/24V, can you get the number?
Also there is a small electrolytics cap next to the MOSFET heat sink, you can try replacing that cap which is the start up cap.
BTW, the two rectifier Diodes for the 12V (Axial lead) and the 24V (TO-220 case mounted on the heat sink) checked OK?

[CraigR]

Re: Vizio VA26LHDTV10T

I assume you mean the tiny chip on the bottom of the board. all I can make out is 23A and under it looks like 4388. I had that cap out and tested with esr meter and is good.Are you talking what I have circled in the picture to check? If not would it be possible to circle what I should check in the picture? Thanks.

[budm]

Re: Vizio VA26LHDTV10T

Those are MOSFET for the inverter circuits, you need the one I marked as 12v/24v SMPS section.

[CraigR]

Re: Vizio VA26LHDTV10T

Ok The diode reads 1337 one way and 228 the other and I'm takeing the other out of circuit now.

[CraigR]

Re: Vizio VA26LHDTV10T

And that reads with the black probe on the center leg 215 for both sides with red lead and OL in any other configuration. Do you think it would pay to pull all the caps out and check them?

[budm]

Re: Vizio VA26LHDTV10T

The only start up cap that I can think off that will not let the IC to start running, the main key is the spec of the IC so we can check the voltage at the VCC pin, but what you can do right now is to check the DC voltage right at the two legs of the start up cap, just be careful because you are working in the primary side of the circuit.

[CraigR]

Re: Vizio VA26LHDTV10T

Well this is weird, I soldered stuff back in and put the board back in to check voltage at that start up cap and now the tv is working. I wonder if it is a heat issue? Most of the time the tv was in my garage where it is kind of cold and I had it in the house all night where it warmed up. 30F here in Wisconsin so I stuck it outside and will let it get cold then check right away.

[budm]

Re: Vizio VA26LHDTV10T

Cap when it is heated up, the ESR will go down, when it is cold the ESR will rise. When I repair, I will automatically replace the start up cap as part of the set of cap to replace. If the cap is not too far gone, I will use hair dryer to heat up the cap to see if the power supply will start up.

[CraigR]

Re: Vizio VA26LHDTV10T

Must be, Just brought it in and dead again. I will see about replacing that cap and get back. Thanks so much for all the help budm! I will report back as I might even have one.

[CraigR]

Re: Vizio VA26LHDTV10T

I pulled out what I thought was the start up cap like you have circled and checked it with my ESR70 and esr was .66 and cap was 9.16 So I tried 2 other caps and still no start up.

[budm]

Re: Vizio VA26LHDTV10T

C841?? I think? Try heating up the board with hair dryer to see if it will start up. It can be cold solder joints some where also since you were able to get it to run.

[CraigR]

Re: Vizio VA26LHDTV10T

C941 and yes I could get it to start with a heat gun.