Vizio VW42L FHDTV10A

[ngoodnight01]

Hello

I acquired this LCD for free and I am trying to fix it. I have found that one of the inverter boards had a fried IC so I replaced the pair as per instructions on this forum. Now I have a picture when plugged into an hdmi source on my laptop but it flickers very fast and makes a very rapid clicking sound. I have looked for bulged caps but have not found them. Thanks for the help

[selldoor]

Re: Vizio VW42L FHDTV10A

Check on the forum for testing voltage regulators - vizio seems plagued with bad ones


Welcome to the forum-
We can help a lot more if you please post good clear pictures of the whole chassis, and then pictures of each board, front and back (in the same orientation) and close up of connectors, (max resolution 2000x2000 and 2MB) using the manage attachments button, which is found by clicking "go advanced" under quick reply.

Please do not post inline and offsite as they slow down the loading of pages.

Examples of what is needed

https://www.badcaps.net/forum/attach...7&d=1280167246

https://www.badcaps.net/forum/attach...6&d=1280167246

https://www.badcaps.net/forum/attach...4&d=1280167246

[johnboy1313]

Re: Vizio VW42L FHDTV10A

Check U7 and U33 on the main board. Well, check them all but I had similar issues on a Vizio GV42 something or other and replacing those 2 VR's fixed it.

[ngoodnight01]

Re: Vizio VW42L FHDTV10A

I am trying to upload pics but the attachment clip is not allowing me to what am I doing wrong

[selldoor]

Re: Vizio VW42L FHDTV10A

Keep them less than 2mb and try and upload one at a time

[ngoodnight01]

Re: Vizio VW42L FHDTV10A

Here is the pics

http://sdrv.ms/ZmK6Qz

[cashkennedy]

Re: Vizio VW42L FHDTV10A

Your pics are probably too big in their current form to be posted with the manage attachments function. I know my 6 megapixel camera from 10 years ago works, but your probably using something in the 12 range.

Not many people are gonna want to "trust" a link like that , but i clicked it and its skydrive which is fine.

As far as your actual problem, you cant visually see that a regulator is bad, so if thats the problem pics arent going to really help... Have you tested the regulators on the main board with a multimeter to see if they are giving the right voltages while the set is plugged in / and on if possible.

I never like trying to diagnose sets via pictures, i prefer to go about it in a logical process > is power supply board outputing the right DC voltages > then check regulators so on.

There is a very good flowchart in the service manual for this generation of vizio sets and explains exactly what voltage each regulator should be outputing.

Based on your actual symptom though , if your just getting flickering in the backlight, and not in the actual picture, then you might have a bad bulb or bad transformers on the inverter board that are skipping some windings (shorting) very rapidly and inconsistently. There are also sometimes caps on the inverter boards that can go bad.

You didnt post any picture of the inverters and thats probably the only thing that might help if your problem is only with flickering backlights.

[ngoodnight01]

Re: Vizio VW42L FHDTV10A

I have them uploaded to my album on this forum how do I link it to my post?

[cashkennedy]

Re: Vizio VW42L FHDTV10A

If your sure its a flickering backlight issue, you could take the set all the way down to the light box (requires careful handling of the LCD as you carefully slide / lift it off the light box) and watch the bulbs while the set is on. If only some of the bulbs are flickering the problem is related to the inverter / bulbs , if all of them are flickering more likely an issue with the power supply or the mainboards control of the brightness.

I dont know how to link pics from your album on the site, but unless youve taken some new pics of the inverters it probably isnt necessary.

[johnboy1313]

Re: Vizio VW42L FHDTV10A

You may not need to lift the LCD screen off. On all of the LCD's I've worked on, when the back cover is off, you can tell from the back when the backlights come on. There are several screw holes that go through the metal case of the panel that allow light through. There is a white plastic sheet inside the case so you don't see the actual bulbs, but you can still tell when the light comes on. If the bulbs are flickering, you should be able to see it.

[ngoodnight01]

Re: Vizio VW42L FHDTV10A

I am getting the correct voltages out of the 24 volt and the 12 volt side to the main board. When I probe the two outlets of u13 ( which is under the heat sink0 I get 1.3volts and 1.1 volts steady. I can see through the holes in the back of the tv especially where the inverter boards plug in that both sides of the LCD are flashing very rapidly. This is doing this with just the TV on and no input to it. If I put an input it shows the input but is flashing very rapidly still.

[tibimakai]

Re: Vizio VW42L FHDTV10A

did you replace the two capacitors on each inverter board?
Do you have the 8.5 Kohm at the FET transistors?

[ngoodnight01]

Re: Vizio VW42L FHDTV10A

I replaced both inverter boards with the updated versions which I have not modified. Which FETs are you referring to?

[tibimakai]

Re: Vizio VW42L FHDTV10A

I thought that you have replaced the chips from those boards.
It could be a bad tube in the screen.