Vizio V0370M Backlight no Picture

[whiz62]

Hello everyone, so glad glad you're back. I picked this up last week and like the heading says, it fires up, logo goes from amber to white and backlights come on.

I checked voltages at psb connectors and here is what I get:

6 pin connector:

#1- 3.11v
#2- 2.96v
#3- 0v
#4- 0v
#5- 0v
#6- 0v

12 pin connector:

#1- 1.53v
#2- 12.2v
#3- 12.2v
#4- 12.2v
#5- 0v
#6- 0v
#7- 0v
#8- 0v
#9- 0v
#10- 5.05v when plugged in or turned on
#11- 5.05v when plugged in or turned on
#12- 5.05v when plugged in or turned on

Only getting .02 volts at T Con fuse.

Checked 1117 regulators on front side of main and here are readings:
U2- in 4.95, out 3.27
U4- in 5.0, out 3.28
U5- in 4.95, out 2.61
U8- in 3.24, out 1.24
U9- in 4.95, out 2.50

The Main board # is 3637-0512-0150 (0A) which I have been unable to locate.

Any help would be appreciated, Thanks

[whiz62]

Re: Vizio V0370M Backlight no Picture

Haven't gotten any feedback on this so thought I would do some attachments since it is up and running. Thanks

[whiz62]

Re: Vizio V0370M Backlight no Picture

Just wanted to let all know it was the Main board. Working fine now.

[budm]

Re: Vizio V0370M Backlight no Picture

Thanks for the follow-up on the repair.
BTW, when reporting the DCV of the LDO regulator (1117), always provide the DCV of the ADJ/GND pin too.

[whiz62]

Re: Vizio V0370M Backlight no Picture

I thought about that after the fact. Will do from now on. Thanks.

[budm]

Re: Vizio V0370M Backlight no Picture

You can tell if the regulator is bad by measuring the DCV between ADJ pin and the Output pin, it should be = to the Vref which is 1.25V.
The output Voltage should be = Vref of 1.25V + Vadj pin. (as long as the input Voltage is not below the min Vin requirement).

https://www.badcaps.net/forum/showth...999#post300999