Question about Televison & Video

1 Answer

I have sound, but no picture on my Vizio VT420M. Any ideas? I changed the one fuse I could see, to no avail.

Posted by on

Ad

1 Answer

  • Level 3:

    An expert who has achieved level 3 by getting 1000 points

    Superstar:

    An expert that got 20 achievements.

    All-Star:

    An expert that got 10 achievements.

    MVP:

    An expert that got 5 achievements.

  • Master
  • 11,361 Answers

First, look at the screen in darkened room to see if you can see any slight glow from the screen, if it does, then the problem can be the T-CON (not getting the 12vdc) or the main logic board not feeding the signals to the T-CON board.
if not, next place to check will be the power supply module, make sure it has 24vdc which is required by the backlight inverter to work, the reason for not having 24vdc can be from bad DC filter caps (leaking/bulging top, high ESR) or short circuits in the inverter board which will cause the 24vdc supply to go into shutdown mode, so you may have to disconnect the power cable that feed the inverter board to see if the 24vdc will work without the inverter board hookup, you will need to apply about 3~4 amp of load to the 24vdc to make sure it can handle that. There are fuses on the backlight inverter boards also. So there are some troubleshoot you will have to do to find out the causes of the problem you are having.

If you are going to DIY and have proper tools, electronics knowledge, and know safety precaution then please read on:

Please see my basic troubleshooting guide here:
http://www.fixya.com/support/r5093881-lcd_flat_panel_tv_troubleshooting_guide

http://s807.photobucket.com/home/budm/allalbums

http://en.wikipedia.org/wiki/Capacitor_plague

Parts: www.shopjimmy.com
Capacitors kit: http://lcdalternatives.auctivacommerce.com/Default.aspx

Posted on Aug 07, 2010

  • 2 more comments 
  • grim509 Aug 07, 2010

    I do have a backlight. The main fuse is good, the small fuse on the T-CON board is good (voltage on both sides). How do I determine wether it is the Logic Bord or the T-CON Bord?

    None of the caps seem to be bad (from visual inspection) none are bulging or have a burnt appearance. I also do not have any of that "tell-tale" failed electronics smell either (the sulfer smell).


    What/where can I check to tell if it's the T-CON or Logic board? Thanks for your help!

  • grim509 Aug 07, 2010

    I do have a backlight. The main fuse is good, the small fuse on the T-CON board is good (voltage on both sides). How do I determine wether it is the Logic Bord or the T-CON Bord?

    None of the caps seem to be bad (from visual inspection) none are bulging or have a burnt appearance. I also do not have any of that "tell-tale" failed electronics smell either (the sulfer smell).


    What/where can I check to tell if it's the T-CON or Logic board? Thanks for your help!

  • grim509 Aug 07, 2010

    I do have a backlight. The main fuse is good, the small fuse on the T-CON board is good (voltage on both sides). How do I determine wether it is the Logic Bord or the T-CON Bord?

    None of the caps seem to be bad (from visual inspection) none are bulging or have a burnt appearance. I also do not have any of that "tell-tale" failed electronics smell either (the sulfer smell).


    What/where can I check to tell if it's the T-CON or Logic board? Thanks for your help!

  • Bud Martin
    Bud Martin Aug 08, 2010

    We need to look at the LVDS (Low Voltage Differential Signal) for the main board LVDS driver IC with the scope, but without the service manual, it will be realy hard to tell if the IC is bad or it is not getting the correct voltages.

×

Ad

1 Suggested Answer

6ya6ya
  • 2 Answers

SOURCE: I have freestanding Series 8 dishwasher. Lately during the filling cycle water hammer is occurring. How can this be resolved

Hi,
a 6ya expert can help you resolve that issue over the phone in a minute or two.
best thing about this new service is that you are never placed on hold and get to talk to real repairmen in the US.
the service is completely free and covers almost anything you can think of (from cars to computers, handyman, and even drones).
click here to download the app (for users in the US for now) and get all the help you need.
goodluck!

Posted on Jan 02, 2017

Ad

Add Your Answer

Uploading: 0%

my-video-file.mp4

Complete. Click "Add" to insert your video. Add

×

Loading...
Loading...

Related Questions:

1 Answer

Vizio VT420M has sound no picture


Back-light problem. Check and replace damaged component/s at its back-light inverter board, or replace this board as card basis. If you wish to get some details; check the site linked here. Surf the site with patience. Pull up older posts. It will be best to replace the inverter board as card basis.
http://electronicshelponline.blogspot.com/

Sep 04, 2014 | Vizio L32 32 in. LCD HDTV

1 Answer

No Picture on Vizio VT420M TV. Only Sound. Any Ideas how to fix it myself ?


I had a similar problem a while ago! I checked up some threads around the web and it was when i found out a tip about replacing the inverter board pannels of the backlight!! guess what ? It worked for me... My Vizio HDTV is about 5 years old so far and it is up and running like a champ...!! I hope it works for you!

Sep 07, 2013 | Vizio GV47LF Television

1 Answer

VT420M no sound or picture and turns off by itself


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

May 27, 2013 | Vizio Televison & Video

1 Answer

Vizio vt420m comes on then flickers and then doesn't show any picture, but the tv stays on


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.

Jul 13, 2012 | Vizio VT Televison & Video

1 Answer

I have a Vizio VT420M. When I turn it on by remote, or power button, the Vizio light changes from amber to white, but I get no picture at all OR sound. Do these symptoms sound like a bad power supply,


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.

Mar 25, 2017 | Vizio VT420M LCD TV

1 Answer

No picture just sound


As of April 7, 2011 Vizparts.com has new shipment of main board #CBPF9D1KZ4 for $250.00 with a $50 core value, and 14 business days to return if not the problem. Also check Ebay search

May 20, 2011 | Vizio VT420M LCD TV

1 Answer

I've owned a Vizio VT420M for just over 13 months. About a week ago the tv started flickering when I turn it on. The picture is visable, but the area around the actors is flickering. After about 7 to 10...


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.

Mar 01, 2011 | Vizio VT420M LCD TV

1 Answer

I was told by a service tech that my vizio tv model VT420M has a bad main board and that the board is not available. I have spoken with 2 more service companys and told the same thing. The set is 5 days...


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

Jan 19, 2011 | Vizio VT420M LCD TV

1 Answer

My Vizio VT420M LCD TV has for several months has changed to a dark screen while viewing without any other problems. We always hit "power/cable" on the HD cable box and it would immediately come...


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.

Jan 15, 2011 | Vizio VT420M LCD TV

Not finding what you are looking for?
Televison & Video Logo

Related Topics:

709 people viewed this question

Ask a Question

Usually answered in minutes!

Top Televison & Video Experts

The Knight
The Knight

Level 3 Expert

74243 Answers

Cindy Wells

Level 3 Expert

5126 Answers

Electro Med Services...
Electro Med Services...

Level 3 Expert

6694 Answers

Are you a Televison and Video Expert? Answer questions, earn points and help others

Answer questions

Manuals & User Guides

Loading...