Vizio m550nv

[Salvamex]

Please help.
I have a 55" vizio that when I connect it to the wall outlet, the vizio orange light flashes a lot of times and after a while it stays orange, I turn it on and the orange light turns to white but with no picture or sound. the whole screen is black.
I opened the tv and got the following readings once the tv was on (white vizio light) on the power supply board where I have placed the red circle on the picture.

from the bottom up
1.86v supposed to be 12v
1.86v supposed to be 12v
3.22v supposed to be 12v
3.32v supposed to be ?

Is this normal? I hope I am making sense and I am sorry for the poor pictures but its night time.

[Phaihn]

Re: Vizio m550nv

you should try to get a closer up picture of the power supply.

[Salvamex]

Re: Vizio m550nv

Here is the close up

[drpj23]

Re: Vizio m550nv

Just to make sure....is the meter set to DC and the correct range (if not autoranging)? Battery Good?

Well with the tv on (white light) what voltage do you get on those central 450v caps? (Probe on each leg)

[Salvamex]

Re: Vizio m550nv

Yes the meter is set to dc and the correct range.
I replaced the battery last week with a brand new one.
Is it safe to test them? the 450v caps?
And I imagine the setting on the meter needs to be on 600v right?
Also, does it matter which probe goes to what leg?
Sorry but I am new to all of this.

[drpj23]

Re: Vizio m550nv

Ok, good.
It is ok to test them but DO NOT short the legs of the capacitor while ON or on standby.
Yes 600v is what you use.
No it doesn't necessarily matter about probe placement - if it is backwards then the voltage reading will just show a negative sign.

Measure while on standby and then again while it is ON.

[Salvamex]

Re: Vizio m550nv

Okay here are the readings:
the bottom one on standby 168v while it's on 396v
the top one on standby 168v while it's on 396v

What do you think?

[Salvamex]

Re: Vizio m550nv

Please help, I know I have bad pictures but it's always dark when I get home from work and it's hard to get good pictures.

[drpj23]

Re: Vizio m550nv

That looks good and pictures are actually OK.

I find it very odd that the 12v rail showed 2 different readings since those 3 wires are connected to the same source. What are you using as your ground? Using 20 on your meter, correct?

[Salvamex]

Re: Vizio m550nv

I am using attached screw to metal frame inside tv for ground.
And yeah I am using the 20v mark on my meter.
What about the readings on the 450 caps?

[drpj23]

Re: Vizio m550nv

The 450v caps look fine.

Are the screws coated? They can mess with readings sometimes (well in my experience).

Use the frame itself or GND on the harness and re-list the voltages with respect to the legend.
CN51
Pin1 - 5v - 4.96v
..and etc. for when the power is on.

[jkdood]

Re: Vizio m550nv

Is there any availability of a service manual (or schematics) for this model please. (CAn buy or beg or trade.) TY.

[Mr Bill]

Re: Vizio m550nv

This tv might be to new for a service manual but there is a repair service on ebay for your mainboard. I'm wondering if its an eeprom chip failure like on the E series vizios.

http://www.ebay.com/itm/Repair-Servi...item2571997fd6

[Salvamex]

Re: Vizio m550nv

Thank you, but what if it's not the main board but the power supply.
I dont want to pay $105.00 for nothing.
I would like to get help here so hopefully I can fix it or buy the right board and not be guessing.

[diodo49]

Re: Vizio m550nv

I had this exact problem on my Vizio 47" HDTV.
I removed the speakers and all the screws on the back cover.
Took the cover off and located the fuses on the largest circuit board.
The are in the upper right hand corner of the board. There are 3 of
them in a row labeled LF 1.5,
LF 3.0 and LF 3.0. The are white in color with copper ends.
I took a volt meter and measured continuity across all fuses individually
and found the LF 1.5 to be blown. The guy at the electronics store sold me a barrel
1.5A fuse and told me to soldier it across the top of the blown fuse.
It took an extra set of hands but the TV works perfectly.

[Salvamex]

Re: Vizio m550nv

Thanks, and I am glad it worked for you, but this is a different model so the boards are different.
I did check fuses f1, f3 and f8 for continuity on the main board and they all work fine.
I am stuck I dont know what to do

[drpj23]

Re: Vizio m550nv

To rule out the power supply give us the voltage readings.

[Salvamex]

Re: Vizio m550nv

Voltage readings of which component?
the one in the bottom it's all black with no marks on it (yellow circle), if it's a fuse it checks out fine. I tested both fuses (green circles)and they are okay .000 on continuity test and my multimeter beeps same as the one in yellow circle. I tested all 6 diodes I can identify (red cricles) and they all check out okay but I have not tested the bridge and the opto-isolators because I don't know how.
I checked all diodes and on the cathode side I get a reading of .480 and when I switch the probes on the on the other end I get 0 reading.
The only diode I get .465 is the one under the 450 caps.
So it means that they are working because the current is only flowing one way on all 6 of them right?

[budm]

Re: Vizio m550nv

OK, on the picture in post 3 the closed up pictures of the connector CN202:
The CN202 has 14 pins, so lets make the top pin #14
Please take the DC voltage readings of these pins:
14 (PWM) = xxVDC
13 (N.C.) not connected
12 (BL_ON: Backlights ON, >3VDC = ON) = xxVDC
11 (PWR_0N: power on >3VDC = ON, the voltage on that 450Vdc cap will go from 170VDC to around 390Vdc due to PFC Voltage booster kicks on which you have already verified) = xxVDC
10~8 (12VDC power supply) = xxVDC
7~4 (Ground) = 0VDC
3~1 (5V standby) = xxVDC

[Salvamex]

Re: Vizio m550nv

okay here we go:

14 (PWM) = .84v
13 (N.C.) not connected
12 (BL_ON: Backlights ON, >3VDC = ON) = 3.3v
11 (PWR_0N: power on >3VDC =3.2v
ON, the voltage on that 450Vdc cap will go from 170VDC to around 390Vdc due to PFC Voltage booster kicks on which you have already verified) = 397v both caps
10~8 (12VDC power supply) = 1.81v
7~4 (Ground) = 0VDC
3~1 (5V standby) = 5.13v
__________________