Vizio E371VL no power, no amber

[ronm6962]

Vizio E371VL, 2 years old, no amber VIZIO light when plugged in, and no other indications of power. I assumed a bad Power Board and replaced it...same results. I tested voltage going into the PS Board and 120v AC is there going in and out of the fuse. The cable connecting the PS Board to the Main Board shows a fluctuating voltage between 0 and 5v DC on pin 1. When I remove the cable, I then get a solid 5v DC, but no 12v reading on the 12v pins. So...I'm thinking the problem must surely be in the Main Board. Any ideas where/what to test on the Main Board to isolate the problem? Or any other ideas? A picture of the Main Board is attached. Thanks.

[budm]

Re: Vizio E371VL no power, no amber

The switched 12V will not be present until the main board sends out PS_ON to turn on the main power supply (12V, and 24V).
It sounds like the main board is drawing too much current and causes the 5VSTBY to go into start-up/shutdown mode, try to find the cause of the problem down to component level is not going to be easy especially without the diagram.

[ronm6962]

Re: Vizio E371VL no power, no amber

OK, thanks for the quick response. So you think I should just go ahead and replace the Main Board, and not try to isolate further since we have no wiring diagrams?

[budm]

Re: Vizio E371VL no power, no amber

There are more than one version of this model:
http://www.shopjimmy.com/catalogsear...q=Vizio+E371VL
It is also know for having bad EEPROM.
You can contact shopjimmy about the main board to see what they suggest, they are really good on helping the customer, it is my main supplier for boards.

[ronm6962]

Re: Vizio E371VL no power, no amber

Yes, I have used ShopJimmy and agree with you. I checked and they do have a board for around $80, but they are not taking tech questions (likely due to the season). So I was hoping there might be a "popular" failure point for this board with this symptom. The board is 3637-0782-0150. I'll likely go ahead and order the board. Thanks again.

[countryguy45]

Re: Vizio E371VL no power, no amber

So did the main board fix your issue? I have a set with the same issues and same main board, has 5 volt standby when main board is unplugged but as soon as you plug it in, the 5 volts leaves, unplug the main board and power cord the reapply power cord then 5 volts is back while main board is disconnected

[countryguy45]

Re: Vizio E371VL no power, no amber

Update, I just checked the power supply and used 2 resistors to force the power supply on. The backlights and all voltages working on the power supply...I am thinking I just got a bad main board even though it was suppose to have been a good and checked board, I will post back if the main board fixes the problem, I am gonna return this one first this Monday

[nomoresonys]

Re: Vizio E371VL no power, no amber

Update, I just checked the power supply and used 2 resistors to force the power supply on. The backlights and all voltages working on the power supply...I am thinking I just got a bad main board even though it was suppose to have been a good and checked board, I will post back if the main board fixes the problem, I am gonna return this one first this Monday

+1 Does seem like the mainboard.

[budm]

Re: Vizio E371VL no power, no amber

So did the main board fix your issue? I have a set with the same issues and same main board, has 5 volt standby when main board is unplugged but as soon as you plug it in, the 5 volts leaves, unplug the main board and power cord the reapply power cord then 5 volts is back while main board is disconnected

Try having just the main board and power supply supply board connected together without other boards connected to the main board to see if the 5VSTBY will be present or not.
You can also check the resistance of the main board 5VSTBY pin and GND pin to see if it shows very low resistance or not.