Vizio M470VSE turning off

[tibimakai]

I'm trying to repair my neighbors TV. It's a thin LED smart TV.
TV can be turned on with the remote, or the side switch.
It will turn on showing the Vizio V logo on the screen for a couple of seconds and then it turns off. Same goes to the Vizio logo in the bezel, turns white and while the screen is on, it will stay on. When the TV turns off, the logo will turn off too.
I have measured all the voltages at the PS and all the voltages are OK, until the power shuts off.
Just in case, I have tested all the heatsink mounted transistors, and diodes and they are not shorted.
25V goes to the LED driver board.
I have tested for shorted FETs and diodes on the LED driver board, they all seem fine.
LEDs get 52V on both rails. I have tested all the test point going to the LEDs and they are all pretty much the same, 9.75-9.84V.
I have opened up the screen, to look at the LEDs, all of them light up.
Not sure what else can I check.
It could be EEPROM problem? If it would be EEPROM, I would expect to find them for sale on some sites, but I haven't seen any for sale.
Any input would be appreciated.

[tibimakai]

Re: Vizio M470VSE turning off

Nobody has any experience with these TVs?
No ideas what to look for?

[tibimakai]

Re: Vizio M470VSE turning off

I have done some measurements and to my eye, they all look good, except some voltages on the LED driver board, which I don't know what they should be.
Here they are:
Power supply main connector:
Power On= 3.3V
AC_OFF_DET= 0.01V
REG_12.5V= 12.46V
BL_ON/OFF= 2.94V
ERWM/IPWM= 1.64V
Power Supply output to the LED Driver board:
25V= 25.2V
L_Det= 0.4V off
L_Det= 0V on
LED Driver board:
Vcc= 5.01V
V12= 12.03V
PWM 1,2,3,4= 2.52V
Fault= 2.5V on
Fault= 0V off
Test2= 0.8V
Test2-out= 5V
Test3= 0.002V
BL_ON= 2.94V
PDim= 1.64V
PDim_2= 2.52V
Output to LEDs:
VLED1= 59.6V
VLED2= 59.6V
CsOUT1-7= 9.8V

The only difference that I'm noticing is the test points differences. I can't find Test1. I remember when I have repaired my Sony 3D TV, the test point differences showed the problem, that it was the driver board.
Could it be the same thing here too?
You guys need a picture?
I'm attaching a shopjimmy picture for now.
Any input would be appreciated.

[stj]

Re: Vizio M470VSE turning off

try running it with the led driver unplugged.
if it wont start, try removing just the "fault" wire.

[tibimakai]

Re: Vizio M470VSE turning off

I don't think there is a fault wire, those test points are on the PCB itself.
I don't remember if I have tried it without LEDs, yet, but I will try it out.

[tibimakai]

Re: Vizio M470VSE turning off

Replaced the mainboard and it's working great.

[budm]

Re: Vizio M470VSE turning off

Hmm, that is strange since the voltages as posted looks normal.Did you check those voltages again to see if they are the same before?

[tibimakai]

Re: Vizio M470VSE turning off

It was my neighbor's TV and I had to rush with it, didn't have time to work on it.
There also over 100 Deg. in my garage.
In my opinion, it was an EEPROM problem.
I have purchased the board to shopjimmy's confirmation. Sent an Email to them and they said, that it is a mainboard issue, what I'm describing.

[budm]

Re: Vizio M470VSE turning off

That is very nice of SJ to give you the info.

[tibimakai]

Re: Vizio M470VSE turning off

I may try this, with my other TVs.

[blscurlock]

Re: Vizio M470VSE turning off

I am having the exact same problem with this model. I have checked the ps and found it to be normal. I will replace the mainboard and post if it fixes this problem for me.