My Vizio vt420m will not turn on what so ever ? Help!

this sounds like a main board failure but a defective power supply can mimic some symptoms of a bad main board. I would recommend you get a diagnosis done on the set. If I was a betting man, I'd guess the main board

Send your email address to me by Fixya comment, and get a copy of the service manual by return mail.

If you have not been using the TV for quite sometime, moisture would have developed some defects inside the TV when you switched on. Sometimes even insects and lizards might get in and cause short circuits. Anyhow this might require attention by a qualified service technician.

Fault at its main digital board. Short circuited component/s at it. Contact any service technician; or the authorized service center. If you wish to get some details; check the site linked here. Pull up older posts. http://electronicshelponline.blogspot.com/ In most cases, the main board might have to be replaced. If so, a software [firmware] update too might be necessary.

Hi, it seems a main board issue but for better assistance you can contact Vizio technical support using the information shown bellow:
Email: [email protected]
Tel: (877) 698-4946 Fax: (949) 585-9563
Hours of operation: Monday - Friday: 6 am to 9 pm
Saturday - Sunday: 8 am to 4 pm
Please have your VIZIO model number, serial number, and date of purchase available before you call.

Hi. Maybe a fuse got burned, you should take it to a service center.

Here is VT420M service manual.
Click it to download.
Thanks.

The flickering is most likely due to a faulty fluorescent backlight. Once the bulb heats up the flickering usually goes away. Some bulbs are easier to replace than others so I would contact your local TV repair shop.

Hi,
I just now called vizio and read your request word-for-word to their technical support person.
They have been known to fix these sets out of warranty. Although the girl said that she wasn't authorized to make that decision.
She told me to have you call this number 877-698-4946 Tomorrow when their level 3 technicians were available. She says that when you call the 1st tier tech support person will then send you one to these senior techs who can make the decision to cover it under warranty. My personal opinion is that they will take care of you. They say the "squeaky wheel gets the grease" I would go ahead and squeak. There is a link I've provided below to help.
I hope the helps,
Mark
http://www.vizio.com/index.php/support/#warrantydetails

Now the tv u turn on u have a flashes of a picture only few sec. and died have sound left only?Yes,than the 2 long boards call the LCD inverter boards are the causes and the problems.These 2 long LCD inverter boards help the LCD screen panel to have a backlight to produced a picture.Tries websites like Shopjimmy.com,Ebay.com to buy those 2 refurbishes long LCD inverter board for the replacement.