Vizio VF551XVT not powering on, standby light on

[n01champion]

I have a VIZIO VF551XVT TrueLED TV.

The power button will not turn on the TV.

PSON = 3.14v
SB5V = 5.10v

When testing the with PSON voltage always remains the same when i press the power button.

A caps look good

Now I am stuck.. please help

[tom66]

Re: Vizio VF551XVT not powering on, standby light on

Thanks for providing pictures.

1. Does the PSON voltage go to >3V immediately upon plugging in the TV?

2. There was a user on this forum who located a similar problem with a Vizio - turned out to be a T-con problem (shorted component.) Try unplugging the two bunched ribbon cables.

[budm]

Re: Vizio VF551XVT not powering on, standby light on

How about other voltages? This power supply also has PFC Voltage booster, does the Voltage on the big cap change from 160Vdc (TV off) to about 400Vdc (TV on). So the PS_ON just stay at 3.14V and no change at all?

[n01champion]

Re: Vizio VF551XVT not powering on, standby light on

Thanks for providing pictures.

1. Does the PSON voltage go to >3V immediately upon plugging in the TV?

2. There was a user on this forum who located a similar problem with a Vizio - turned out to be a T-con problem (shorted component.) Try unplugging the two bunched ribbon cables.

1. Yes the voltage goes to >3v upon plugging it in

2. I tried unplugged the 2 bunch of ribbon cables that go to the T-con board and still nothing

[n01champion]

Re: Vizio VF551XVT not powering on, standby light on

How about other voltages? This power supply also has PFC Voltage booster, does the Voltage on the big cap change from 160Vdc (TV off) to about 400Vdc (TV on). So the PS_ON just stay at 3.14V and no change at all?

What big cap are you referring to on the power supply?

the PS_ON stays at 3.12V and does not change at all

[selldoor]

Re: Vizio VF551XVT not powering on, standby light on

on the main board c443? bottom right looks brown on top, is that just the light.
Also in that area just in front of the connector is a small white box board label f3.
F1 & F2 may be at the top right corner in front of the connector. Please check all 3
power off -meter on ohms - one probe each side of fuse - report result - should be the same as touching the probes together.


edit big cap marked in yellow on pic

[n01champion]

Re: Vizio VF551XVT not powering on, standby light on

on the main board c443? bottom right looks brown on top, is that just the light.
Also in that area just in front of the connector is a small white box board label f3.
F1 & F2 may be at the top right corner in front of the connector. Please check all 3
power off -meter on ohms - one probe each side of fuse - report result - should be the same as touching the probes together.


edit big cap marked in yellow on pic

c443 is just the reflection of the light. its fine

F1, F2 and F3 all report 0.00 Ohms

The big cap on power supply sits at 338V when TV is on standy

[selldoor]

Re: Vizio VF551XVT not powering on, standby light on

Just to be sure - Did you measure the cap with meter on vDC?

Meter on DC 600v black probe on negative leg, red probe on positive leg
Polarity is important & care as high voltage involved.

Does the remote operate the tv at all

[n01champion]

Re: Vizio VF551XVT not powering on, standby light on

Just to be sure - Did you measure the cap with meter on vDC?

Meter on DC 600v black probe on negative leg, red probe on positive leg
Polarity is important & care as high voltage involved.

Does the remote operate the tv at all

The remote does not operate the TV

ok I re-measured Vdc on the large cap..

TV unplugged - 160Vdc
TV standby - 395Vdc

[selldoor]

Re: Vizio VF551XVT not powering on, standby light on

Which cable goes to the button board colours or J number if you can see it in photos. Is the remote sensor on the button board. What happens if you plug
the set in with the button board disconnected.

[n01champion]

Re: Vizio VF551XVT not powering on, standby light on

Which cable goes to the button board colours or J number if you can see it in photos. Is the remote sensor on the button board. What happens if you plug
the set in with the button board disconnected.

The button board is built into the main board (bottom red area) and the cables for the sensor (top red area) is either J4 (middle) J6 (left)

When I had sensor plugged out TV still does not turn on

Let me know if you need better pictures

[n01champion]

Re: Vizio VF551XVT not powering on, standby light on

Guess the help stops here

[JimmysTGP]

Re: Vizio VF551XVT not powering on, standby light on

If you have standby voltage 5V and PS-on is not responding to you pushing the power button, your Main control board is not activating the power on sequence, then your Main board is your problem. However if you have 3.12v then that would represent it is running and should give you atleast voltage on your LED 38V to 59v see if you have these voltages if you do then sounds like your flash IC did not turn the TV on properly, which in case would still be your Main board.

[selldoor]

Re: Vizio VF551XVT not powering on, standby light on

"Guess the help stops here"

Not necessarily! But perhaps no-one feels they can help. We are all volunteers on here.I dont know a lot about Big Tvs and less about LED ones.I usually just get the simple tests done and hope the experts will step in.Sometimes posts just drop off for one reason or another e.g I went on holiday at the beginning of May.
Anyway, What I was trying to suggest was that if the buttons were on a separate board that you could unplug and the remote sensor was on another board you could unplug the buttons and try and switch on with the remote.
This would eliminate a problem with the buttons.
I dont think we can do that. - still not sure where you are saying the buttons are? Bottom Red Area?

EDIT _ Found it I was still on the earlier pics

Next I dont think you have posted any readings for other voltages (Budm post3) whilst he continued on about the mains voltage and PFC I think he expected you to post the
Voltages off all the connectors on the power supply.

Power needs to be on and meter set on 200VDC Put Black Probe on the corner screw near CN3 and with the red probe work down the connectors and post as follows
CN3
Pin 1 24v Actual xxv
Pin 2 24v Actual xxv and so on

Was it your set and were there problems prior to it not switching on? or was it just normal then one day nothing?.
Any 3rd part intervention (small children with a desire to turn things on and off as many times as possible before being caught)

Also in bottom left corner of main board is there a fuse F4 - cant quite tell. If it is test it.