Chosen Solution
Howdy! ive got here this 2012 vizio m420vt, most beautiful 1080p ive ever seen. in the past its had an intermittent issue where the audio wouldnt work, and i would have to unplug it and replug it many times before it resolved itself. Well, after months of sitting in the office i decided to pull it out to play some 1080p content, and to my horror there were wretched vertical lines all over the tv, looking like it had been physically damaged. I had consigned this to physical damage, until just for a few minutes it went back to normal, and right back to hellish lines. so figuring this was not the product of something accidentally bumping it and breaking it, i plugged in my switch and immediately noticed severe LAG and freezing, as if i was streaming video on poor wifi or something. there is intense lagging, skipping, and ghosting of the image. and, no sound! I am hoping that this is simply a board repair job, and hoping for advice on narrowing down which board to start with as i dont have the cash to throw money at parts. I understand this is a 12 year old tv, but I am very attached to it, the picture quality is stunningly sharp and colors are rich and deep; this 1080p rivals medium and low end 4k sets from modern times. thanks so much for reading and I look forward to any answers. here is a video of the problem. https://youtu.be/ttNJ4OokCsw Update (04/13/2022) example of how the issues appear as soon as the TV is powered on regardless of any inputs being used https://youtu.be/fl616Ni4Cv8
Hi, If possible try connecting a different signal source to a different input type and check the display to see if the problem can be isolated further, e.g. dvd player to the component video input (red, blue, green video +red&white audio cable) and/or to a TV antenna to the RF coax input. If they’re OK then try each HDMI port on the TV, one at a time and check. Note- It is unwise to hot swap i.e. unplug/plug a HDMI cable when the TV and the signal source that the cable is connected to are both powered on, as there is a possibility of damaging the HDMI controller in either device. Turn off both the TV and the connected device before unplugging and plugging in the cable Update (04/14/2022) Hi @ Bell It seems as though the contrast in not being controlled correctly for that section of the screen and the vertical lines seen down the middle initially on startup also point to that I think. The horizontal lines that you zoomed in on, I’m not sure are relevant, as to me they don’t seem noticeable when viewed from the normal viewing distance in your video and sometimes can be seen if you get too close to the screen. Hopefully they’re not noticeable at normal viewing distance as a horizontal line problem is in the screen and cannot be repaired. The screen would have to be replaced and given that it is very difficult to find a replacement screen in the first place, coupled with the cost of it if you do, (nearly half as much as a new TV) then usually it’s not worth it. Disconnect the power from the TV and then remove the back cover and inspect the boards for any obvious damage. On the power board this would be swollen or leaking capacitors and heat affected components i.e. they look burnt or the board where they are positioned looks singed compared to other sections of the board. On the mainboard a lot will be covered by a shield so all you can do is look it over for the same thing. Post some close images of the two boards in your question as maybe something can be seen that you may have missed. Here’s how on ifixit Adding images to an existing question I’m not sure but maybe try replacing the mainboard first. The supplier is an example only to show the cost of the board. If you decide to try this option ( I realize you said that you were broke) verify with whichever seller you choose that it is the same board as yours. Compare the model number printed on the board to make sure. Check what the seller’s returns policy is if the mainboard is not the problem as you may get a refund, minus shipping costs
