Vizio VX37LHDTV10A

[budm]

Re: Vizio VX37LHDTV10A

When you work on any electronics equipment, first thing to verify is the power supply section, bad power can give a lot of problems.

[tibimakai]

Re: Vizio VX37LHDTV10A

I guess I will have to stop by Pep Boys today.
Do you suspect the power board also?
Initially I haven't considered it because it was outputing the right voltages.

[budm]

Re: Vizio VX37LHDTV10A

This is how I test the power supply module, I hook up 6v lamp to the 5VDC stanby power supply out put, 24vdc lamp (two 12v lamp in series) to 24vdc output, 12v lamp to the 12vdc output. When you apply the 120v to it, you should on ly see the 6v lamp on, when you apply 3.3~5vdc to the PS_ON, then the 12/24vdc lamps should come on, this is the typical setup after you inspect the FSP power supply module. Sometime you have to check if PS_ON is active high or active low control signal type by tracing out the traces on the board.

[tibimakai]

Re: Vizio VX37LHDTV10A

here it is:

[budm]

Re: Vizio VX37LHDTV10A

By the way, can you also post the picture of the output connectors so we can read the Voltage labels?
Never mind, I got the pinout from FSP website:
http://www.fspgroupusa.com/fsp2013m01/p/684.html
See what I can figure out.

[tibimakai]

Re: Vizio VX37LHDTV10A

you see, I haven't checked that way when the PS_ON wire is removed, I will have to do that when I'm going home.
I only checked it with the main board connected to the power supply and then I have checked the voltage on the removed PS_ON wire.

[budm]

Re: Vizio VX37LHDTV10A

Let me get this straight, when the PS_ON cable is not attached to the power supply, let say that you have the 120v connect to the power supply and nothing else is attached to it, you have 12v and 24v at the output?

[tibimakai]

Re: Vizio VX37LHDTV10A

Here they are:

[tom66]

Re: Vizio VX37LHDTV10A

Can you post a photo of your power supply? Clear and in focus, and from the top as well as the bottom. I'll try to highlight some checks you can do.

[tibimakai]

Re: Vizio VX37LHDTV10A

I kind of went over to Tetranitrate and posted there.
So I have removed the T-con connector and the PS_ON did not change.
I have even started the TV w/o the T-con and the backlight still flashed for a second like before when it was connected.
I have tried Tetra's idea to disconnect the PS_ON wire from the connector and then I got 3.31V as it should be. Same happens with T-con disconnected, so I don't have the same issue as him. I have checked those caps and they are not shorted.
With only the power supply and main connected the PS_ON is 2.16v, but if I disconnect the wire from the connector it goes up to 3.31v, so it must be something in the power supply or something on the main that acts weird when is under load.
I don't see a reason to do the resistor test on the power supply since I have the 12 and 24V, even with this low PS_ON.

[tibimakai]

Re: Vizio VX37LHDTV10A

T-con can bring down the PS_ON voltage?
If I disconnect it the PS_ON should go back to 3.3v?
T-con boards just have to be replaced, we are not fixing it?

[tom66]

Re: Vizio VX37LHDTV10A

To me the voltages on the regulators look good too.
I haven't removed that cable. that's the one thing that I haven't touched yet.
I heard some they had T-con issues, do you suspect that with my set?

I would try that. Tetranitrate rushed around attempting to diagnose a problem with the main board and power supply, before finally finding it was a T-con that had shorted.

[tibimakai]

Re: Vizio VX37LHDTV10A

To me the voltages on the regulators look good too.
I haven't removed that cable. that's the one thing that I haven't touched yet.
I heard some they had T-con issues, do you suspect that with my set?

[tom66]

Re: Vizio VX37LHDTV10A

the u33 gives the PS_ON voltage?
at the u33 I have 5.05v, 3.31v and 2.06v and the PS_ON is 2.16v.
all measured from a mounting screw to the case.

That seems okay then. I think you've got a different board where U33 is under less stress. Most often U33 is not an adjustable regulator, but fixed.

Have you tried unplugging the LVDS cable? It's the long thin connector which bundles into a black wire and goes to the LCD controller (T-con.)

[tibimakai]

Re: Vizio VX37LHDTV10A

the u33 gives the PS_ON voltage?
at the u33 I have 5.05v, 3.31v and 2.06v and the PS_ON is 2.16v.
all measured from a mounting screw to the case.

[tibimakai]

Re: Vizio VX37LHDTV10A

chasy or screws
most of the "U" have this 2.06V for pin 1
at U9 is 3.31v, 1.5v, 0v so here the 1.5v difference it's OK?

[tom66]

Re: Vizio VX37LHDTV10A

Thanks.
I will double check my measurments.
It's interesting because the first time I have checked all the voltages they were all OK, I had 3.31v for PS_ON and yesterday it was 2.13v.
The U33 has 5.05v, 3.31v and 2.06v. The pin 1 shouldn't be 0?

3.31V - 2.06V is 1.25V, so it seems to be okay, but just in case it's a coincidence...

Where is your black probe connected?

[tibimakai]

Re: Vizio VX37LHDTV10A

Thanks.
I will double check my measurments.
It's interesting because the first time I have checked all the voltages they were all OK, I had 3.31v for PS_ON and yesterday it was 2.13v.
The U33 has 5.05v, 3.31v and 2.06v. The pin 1 shouldn't be 0?
I forgot to add to my first post, that the backlight blinks and then turns off after turning the TV on.

[tom66]

Re: Vizio VX37LHDTV10A

U33 fails giving an output voltage of around 2V. Since your PSON is around 2V (PSON is powered by the 3.3V generated by U33, from what I understand), I would suggest you re-check this device to make sure it isn't failed. I had a Samsung TV with a voltage regulator that was intermittently outputting 1.3V(bad) or 2.5V(good), and causing it to occasionally work (but only 10% of the time), so double check the TV definitely doesn't work when you take the measurement.

[tibimakai]

I have read everything about Vizios on this forum and I'm still not sure if I have the common U33 issue or not.
Tv starts up and shuts down with remote or button on the TV. Yellow Vizio logo when power cord is plugged in and it turns white when the TV is turned on and stays white.
It has most of the voltagages correct except the PS_ON which is low(2.13V).
I have measured all the common U components and they all seem OK except across U9 between pin 1 & 2 I have 1.5V, not 1.25V as on the others.
Could it be a problem? If I measure from the gnd it looks OK though. 3.31v in and 1.5V out.
Fuses are all OK, I have checked on the T-con too.
Inverter board is the one which PainBill said that it's famous on going bad, sorry I don't have the model number with me right now, but it's a single long board on the left side of the TV. 24V it's going to this board also.