Vizio E420i-A0 - No Power

[LedTVDave8]

Hello all. Hoping that someone will shed some light on why my son's Vizio LED tv will not power on. I removed the back cover from the unit and now I see two boards. I believe one is the power/LED board and the other the main board. Nothing happens at all when I press the side power button or use the remote to turn the unit on. How do I verify which board is bad?
Thanks!!!

[budm]

Re: Vizio E420i-A0 - No Power

You can start by posting the bask side of the TV showing all the boards and how they are connected together, then the straight shot pictures of the power supply board and the main board.
Then you will take the DC Voltage readings of each pin of the connector on the power supply board that goes to the main board, you MUST pin down the pin names and follow by the Voltage readings so we do not have to guess what each pins are. Black probe of the meter on the metal chassis.

[LedTVDave8]

Re: Vizio E420i-A0 - No Power

Thanks for the fast response budm. Here are the photos you requested. Readings to come.

[budm]

Re: Vizio E420i-A0 - No Power

Very good pictures! Makes it much easier for me to see. Please also take the same straight shot of the bottom side of the power supply board too so I can trace out the circuits.
https://www.badcaps.net/forum/attach...5&d=1510369656
Just check the Voltages on those pins.
What kind of camera and lights did you use to take the pictures?

[LedTVDave8]

Re: Vizio E420i-A0 - No Power

Ok. Can I take the readings on the power board connector by the pins/contacts on the other side of the black cables? Also, I assume my voltmeter should be set on 20 V DC. And...does it matter if the power button is on or off? Not sure since nothing happens when I press this button. Thanks!

[budm]

Re: Vizio E420i-A0 - No Power

You can run the power supply board by itself with it just connected to the incoming AC without having any other connection to other board, we just want to find out if you have standby Voltage or not first.
https://www.badcaps.net/forum/attach...5&d=1510369656
Pin 1 (where the triangle symbol is) and pin 2 are the 5V standby power supply output pins.

[LedTVDave8]

Re: Vizio E420i-A0 - No Power

The TV is face down on my breakfast bar between the dining room and the kitchen. Excellent light. And for the camera...my Samsung Galaxy S7. As for taking shots under the power board, I would rather not remove any of the boards unless absolutely necessary. I attached a shot of the back side of the board from shopjimmy.com.

[LedTVDave8]

Re: Vizio E420i-A0 - No Power

No readings from either pin (1 or 2) or any of them. Can you confirm that 20 V DC is the correct voltmeter setting? Thanks

[budm]

Re: Vizio E420i-A0 - No Power

https://www.badcaps.net/forum/attach...3&d=1510369656

There are 2 fuses on the power supply board, no power to the board then check the resistance between the two ends of the fuse, it should show < 1 Ohms of resistance.

[LedTVDave8]

Re: Vizio E420i-A0 - No Power

Here is where you lose me. I assume the two fuses are the silver cylinder looking objects. I imagine I should unplug the unit first? Also, I have a Klein Tools MM100 multimeter. What settings should I use? 2K? Not sure how to convert 1 Ohm to my meter settings. Thanks again for the guidance and patients.

[CapLeaker]

Re: Vizio E420i-A0 - No Power

With the PSU unplugged, set your DMM to 200 or 2k, put one lead to one side of the fuse and the other lead on the other side. You should read a short (either 0 or 1 Ohm). If it is open, the fuse is bad. The fuses are Zylinder, silver looking things with the white glass in the middle part. One is a T5, the other a T2.

[LedTVDave8]

Re: Vizio E420i-A0 - No Power

Thanks for all the help Budm (and CapLeaker). I replaced the power last week and the TV works great now! I know replacing a fuse or two is cheaper than replacing the entire power board, but I still saved hundreds by not having to buy a new TV. Happy Holidays!!!