Vizio VO42L FHDTV10A No Picture

[Booman]

My vizio VO42L stopped working yesterday. I have sound but no picture. I put a flashlight up to the black screen and could see images. From what I have read, this is usually the inverter that has gone bad.

I decided to check all the boards for any visible issues. The only one I could find that was possibly an issue from the visual inspection was on the inverter board, which I have circled on the attached photo. You can see where the white cap is missing. Not sure if it was an oversight during manufacturing or if it is something that occurred during use.

The tv powers up fine, just no picture. I do not see any signs of the backlight when I turn it on.

Am I on the right path in replacing the inverter. Also, I have taken out all of the fasteners from the board but it will not move. Do they use some type of adhesive on the newer tv's to hold the boards in place? If so, do I just get a little aggressive with it to remove the board. This seems a lot more delicate than what I have worked on in the past, try 20 yrs ago.

Thanks,

Brent

[budm]

Re: Vizio VO42L FHDTV10A No Picture

Do you have 24VDC feeding the inverter boards? Do you have INV ON/OFF (BL_ON, >2.5V whne TV is on) on the inverter boards?

[Booman]

Re: Vizio VO42L FHDTV10A No Picture

I do not have a digital multimeter as I have been able to get by with my old analog one. Again, 20 yrs since I have worked on a tv. I have power to the inverter board through the 24 vdc, just not sure of the exact levels. Not sure how to check if the backlight is on or off other than a visual inspection. I do not see any signs that the backlight is working.

Thoughts? Thanks!

[budm]

Re: Vizio VO42L FHDTV10A No Picture

Picture #3, you can see white box with printing telling you which pins are for, it is just above the white connector.
There is white surface mounted fuse that you need to check also.

[Booman]

Re: Vizio VO42L FHDTV10A No Picture

Thanks budm. Not in front of the tv at the moment but will take a look tomorrow. I did check the fuse previously and it appears to be ok.

[Booman]

Re: Vizio VO42L FHDTV10A No Picture

Ok, I checked the Von/off (#12) and it had a reading go about 8.

Unfortunately, the probe slipped (long story involving kids) and touched lead #5 which caused a spark. See picture.

I rechecked the fuse and it now registers 0 on ohms.

So the fuse looks to be blown but it does not answer the question of what was my original problem. Since the inverter looks to have power, is that my culprit and do I just go ahead and replace it or is there another option or additional items to check before moving in that direction?

Thanks for the help,