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What is killing my tcon board?!?


Symptom: vertical colored bands on display


Power supply- all listed voltages to master, slave, and main are present and steady.

I skipped a few voltage tests on this repair as ive seen this before. i immediately was trying to determine if it was display vs tcon. unplug tcon, vertical bands dissapeared immediately and the tv was fine. Replaced tcon board and the tv would turn on and shut itself down. while trying to read cycling voltages on main board and tcon, about the 5th cycle, the vertical bands are back and again, dissapear when i unplug the lvds to tcon.

My interpretation of this is that something blew the tcon. i am ordering a new board again and this time will check components from the known good vs the 2 that are “blown”. just trying to get thoughts on where i should be looking.

The tcon board is an auo brand t420hw01 v2 / 07a33-1b, but i think its something blowing the board so perhaps a clue on what would be blown on this board may help.

The main board is eax42405502 (10) - im thinking this may be the culprit, but am unsure what to check to see if it is allowing over current to tcon. (need schematic or expertise)

The driver boards im thinking are good,as the backlight is lit and it is not connected to the tcon in any fashion.

If it was the lcd display, the lines would still be present regardless of the tcon i suppose. if it is a voltage issue blowing the tcon, the display is just a feedback loop through tcon to main board as opposed to the main board being the output to the tcon. is my thinking in the ball park on this?

any help, thoughts, proper voltages lol would be greatly appreciated.

Update (02/26/2020)

Block Image

Block Image

So this image is from the new board ordered, after power cycling a few times while getting readings. it would turn on and then shut itself down. like the original board, now the tv stays powered on with the lines. once i disconnect the tcon, the lines disappear and the tv stays powered on with backlight. Off of what you had posted in your reply @oldturkey03 , it appears that the driver boards are connected to the powerboard and the lcd panel. the tcon board is connected to the lcd panel and the main board. if the driver boards and tcon are connected on this unit, it is internal and through the lcd it appears. it looks weird haha. but to trouble shoot the driver boards, i have disconnected each side of the lcd boards one at a time and the the tv will go through post and shut down.

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So… trouble shooting further:

Disconnected each side of the tcon boards, one at a time…lines still there. unplug the main board, lines disappear. so with either the tcon or the main board unplugged, the lines are gone, backlight is lit and the unit remains poewered on. I was thinking it could have been the main board this whole time, but the results with the new tcon board are throwing me off. upon installation of the tcon, it would just post and shut down. now it stays on with lines like the original tcon board. my suspicions are pointing still to the main board….but why the change in behavior upon the new tcon? time to teach me good sir


I have had three new TV's plugged into the same wall outlet and all three of them blew the t-con board. Has to be something in house current. bought one new t con and it lasted 30 minutes and boom!


@dcarney4141 ... with my experience, the tcon continues to blow due to either the panel (most likely) or the main board (second most likely).

if you wish to test your theory about the electrical, you will want to use a multimeter and check for steady current and also min max for any spikes or fluctuations.


I would agree BUT three new TV's with all new cables and all. Panel not likely on three TV's. It has a Roku hooked up also and it is brand new. Besides had same issue with old Roku. Have an older house with older wiring and a window air conditioner. A120v conditioner. Roku and TV is all that is plugged into wall outlet.


Hi @dcarney4141

Does the air conditioner have its own fuse in the power box, separate from the wall outlet power supply fuse(s)?


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update and solution:

so i was troubleshooting without schematics or listed voltages on the tcon or mainboard supplying tcon board. i knew that if i disconnected the tcon or after further testing…the main board, the vertical lines would disappear. i tried replacing the main board after i had the same symptoms from the new tcon board, although after installation of the new tcon, i had different results at first, but ultimately the same issue. still havnt determined as of why. But the new main board had solved the issue of vertical colored bands on the display.

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@jostewcrew post some pictures of what your screen displays. Not convinced that this is a true T-con error. Check your LVDS cables and the cables on the LCD driver board. “driver boards im thinking are good,as the backlight is lit and it is not connected to the tcon“ the driver boards are directly connected to the t-con board via ribbon cables unless I am missing something here. The main board is the one that could in theory be the culprit.

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jostewcrew zal eeuwig dankbaar zijn.

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