Vizio E420i-AO No pix NO sound & NO Menu !!!

[Ron.M]

Dear Person;...


I'm re-posting this because I did NOT have the model number in the original post , it did NOT show up in the forums listings & I got a lackluster response...
NO OFFENSE INTENDED ReeceyBurger123 , but , I'd like someone who is an experienced tech to reply..
Thanks for your input...

"""Dear Person;...

First time posting here...
I'm a retired analog TV tech with 50+ years experience , 20 of which are self employed owning my own business....
That said...

I have been battling repairs on my Vizio model E420i-AO LED TV..
It was given to me by my ex-landlord's lady friend...
The original symptom was No pix, NO sound & NO menu...
Did the "flashlight test" & there was NO sign of video of any sort or a Menu...
The TV was turning ON , but , there were NO backlights..
After locating & replacing 6 defective LED Strips, I did get a pix..
See attached pix Vizio #2..
The TV turned on with a shading on the right side of the screen...
After a minute or two the pix got steadily worse...
See pix #1717...
After some more time the pix went to vertical lines on both sides of the screen..
See pix #1711-1...
That is the left side of the screen with part of the right side showing...
Pix #1715 is the right side..
When I used some freeze spray in the red circle in pix Vizio #3AB , the pix nearly totally returned to normal , albeit NOT 100%..
I think that that's where the Micro is located...
So , the Main Board was defective..
I got a replacement that turned out to be a dud..
That one went back & got a refund..
The next Main Board did turn the TV on..
However , there's NO pix , NO sound & NO Menu...
This is where I'm at now...
The last pix IMG_1725 is what I'm getting now...
The red dot is from the camera..
The vertical lines are ONLY on the left side...
IMHO , I think the LED Panel IS OK !!..
Reason is that the lines on the left side are different between the 2 replaced Main Boards & the absence of lines on the right side of the screen..

Your help & expertise ARE GREATLY APPRECIATED...

THANK you VERY MUCH in advance...


Later...Ron.M...

BTW:...
I will delete as much or all of the other thread...
Sorry about this , but , I'm looking for someone who can give me some solid info as to the cause of this problem..
THANK YOU VERY MUCH for your patience & hopefully your understanding..
Well , bad news !!!
Can NOT find a Edit button for the other thread !!!...........
So , it stays... ...
Have a GREAT day & weekend...

[dick_barton]

Re: Vizio E420i-AO No pix NO sound & NO Menu !!!

If you remove the screen and using your freezer spray, try to narrow it down further.

[Ron.M]

Re: Vizio E420i-AO No pix NO sound & NO Menu !!!

dick_barton ;...

HUH !!!!!!

How am I supposed to see anything by removing the screen ???
PLEASE let's be nice !!!!
ALL I'm looking for is a LEGITIMATE second opinion !!!..
Please keep in mind the what goes around , comes around.......

Have a GREAT day & weekend..... ...


Later...Ron.M..... ..

[budm]

Re: Vizio E420i-AO No pix NO sound & NO Menu !!!

So on the original board did you try removing that metal shield to see what are underneath? The shield looks to be used for heatsink also so may be it is not making good contact with the chip.
'the pix nearly totally returned to normal , albeit NOT 100%' So after cooling the bands are still present but less noticeable?
Before the LEDs went out the pictures on the screen were OK? I wonder if something may be loose or damaged (such as tab bonding area) when the screen was removed to replace the LEDs.

[dick_barton]

Re: Vizio E420i-AO No pix NO sound & NO Menu !!!

When I used some freeze spray in the red circle in pix Vizio #3AB , the pix nearly totally returned to normal , albeit NOT 100%..
I think that that's where the Micro is located..

The metal screen that you were freezing not LCD panel

[Ron.M]

Re: Vizio E420i-AO No pix NO sound & NO Menu !!!

dick_barton;...

The metal screen that you were freezing not LCD panel

In my part of the world , that's called a shield !!!
And , no I did not..

budm;...

THANK you VERY much for your reply..
I was hoping that you'd jump in...

The original Main Board is now dead & will not turn the TV on....
That's one reason I ordered a replacement that appears to also be bad !!!

'the pix nearly totally returned to normal , albeit NOT 100%' So after cooling the bands are still present but less noticeable?

That was the case with the original board till it went south !!!
With the replacement I get ONLY vertical lines on the left side ONLY & not both sides as the original did..

Before the LEDs went out the pictures on the screen were OK?

Before the LED Strips were replaced , there was NO pix , NO sound & NO menu even with the "flashlight test..
So , I have no clue as to what was going on till the LED Strips were replaced..

I wonder if something may be loose or damaged (such as tab bonding area) when the screen was removed to replace the LEDs.

That could be a possibility...
I DID use EXTREME CARE when dismantling & re-assembling the TV..
While the chance of that does exist , there remains some doubt that that has happened..
Reason is that I expected a pix or at least a Menu with those vertical lines on screen as the original Main Board gave me..

THANK you for your reply...


Later...Ron.M......

[budm]

Re: Vizio E420i-AO No pix NO sound & NO Menu !!!

OK, we just want to get some history of what the TV was doing before the works was done.
Vertical lines just on section of the panel is not possible per SONY training manual to be caused by main board.
Video Process Failures: All video inputs received by the video process circuits are handled on a frame-by-frame
basis. The video frames are converted and scaled to 8 or 10-bit RGB information. It is virtually impossible
for the video process circuits to cause a problem on a specific area of the screen. Failures on this board usually
appear as distortions, color level shifts, video level shifts or noise that involves the entire picture. The TCON can
generate symptoms that appear to be video process related but the video process circuits cannot produce the
symptoms of a failed TCON circuit.
The attached PDF may help you understand how the LCD TV functions.

[Ron.M]

Re: Vizio E420i-AO No pix NO sound & NO Menu !!!

budm ;....

Are you saying that the Tcon board is the problem ???


BTW;...
On another forum (ShopJimmy) & elsewhere , I read that "Horizontal" lines are always caused by a bad LED Panel..
These are vertical , so I presumed that the LED Panel was/is not the cause..Correct ???


Later...Ron.M...

[budm]

Re: Vizio E420i-AO No pix NO sound & NO Menu !!!

T-CON or tab bonding in that section where the vertical lines are.
What happen if you flex the screen? Already try cleaning and reseating the cables/connectors at both ends between the LCD panel and the T-CON?

[Ron.M]

Re: Vizio E420i-AO No pix NO sound & NO Menu !!!

budm;....

OK , that's some good news & some bad news...

Already try cleaning and reseating the cables/connectors at both ends between the LCD panel and the T-CON?

Yes & no..
See pix below...
There is NO TCON Board as such..
The Tcon circuitry MAY be on the Main Board..

I cleaned both ends from the Main Board to the LED panel with 91% Isopropyl Alcohol...
Did not drench them , but , gave each plenty of time to dry out before reconnecting...

I will try to flex the screen sometime tomorrow & get back to you then...
It's a 42" TV so it will be fun flexing it !!!
I took a pix of the full screen so you can see it all...

THANKS.......


Later...Ron.M........

[budm]

Re: Vizio E420i-AO No pix NO sound & NO Menu !!!

The stand is attached to that metal panel, so what is under that metal plate where those two white flat ribbons go to, also since the panel has the tab bonding on the bottom side of the screen, they tend to get damaged by the liquid that people spray on the screen and then seeps on to the tab bonding board and corrode the connections.

[Ron.M]

Re: Vizio E420i-AO No pix NO sound & NO Menu !!!

budm;...

There is nothing under the metal plate...
The ribbons go to connectors at the bottom...
NOT directly to the LED Panel , but , to a skinny circuit board that runs along the bottom of the TV... (Approx 6" , IF memory serves !!)
See attached pix..

BTW;...
I checked the connections when I cleaned the ribbons..
They looked OK...

Later..Ron.M.......

[budm]

Re: Vizio E420i-AO No pix NO sound & NO Menu !!!

OK, so the T-CON is on the main board as you described. This is tough one.
https://www.badcaps.net/forum/attach...6&d=1461954143
By the way, I see only color bars on the screen but no images, is that right at this point? I expect if the main board is good you will get the images behind the vertical lines.

[Ron.M]

Re: Vizio E420i-AO No pix NO sound & NO Menu !!!

budm;....

By the way, I see only color bars on the screen but no images, is that right at this point?

Yes...

I expect if the main board is good you will get the images behind the vertical lines.

I think we are in agreement here..
My feeling is that IF the Main Board IS good . I should at LEAST see a Menu...
I can not see any images
Since there is no onscreen Menu , I can not scan for channels..
What say you ???


Later...Ron.M.......

[budm]

Re: Vizio E420i-AO No pix NO sound & NO Menu !!!

I agree, one thing you can try is to have one ribbon connected one at a time to see what you will get on the screen. I hope that there no shorts circuit on that tab bonding board which took out the T-CON circuit on the main board.

[Ron.M]

Re: Vizio E420i-AO No pix NO sound & NO Menu !!!

budm;...


Be back in about 10~15 minutes with pix...
THANKS...


Later..Ron.M........

[Ron.M]

Re: Vizio E420i-AO No pix NO sound & NO Menu !!!

budm;.....


Ok , here you go..
All the pix below are in sequence..
First starting with the left ribbon...

In the far right pix there are some bright spots in the white part of the screen...
Those are due to the LED diffuser screens not being put back in their proper sequence..
IF we solve the current issue , then I intend to correct that error..


THANK YOU...



Later..Ron.M.......

[budm]

Re: Vizio E420i-AO No pix NO sound & NO Menu !!!

I need to look closer at the T-CON circuit section on the main board, there should be a small SMD fuse for the T-CON circuit.
I see P/N AMTRAN ????-2271-5032
And the numbers on the top right barcode sticker 3642-1792-015???
This one?

Vizio 3642-1792-0150 (0171-2271-5032) Main Board for E420I-A0
http://www.shopjimmy.com/vizio-3642-...r-e420i-a0.htm

So far I do not see the fuse (the other two white fuses are for the 5V and SWITCHED 12V) for the T-CON circuits.

[Ron.M]

Re: Vizio E420i-AO No pix NO sound & NO Menu !!!

budm;...

The full number is;...
3642-1792-0150 (2D)
0171-2271-5032

There you go...

The board at Shopjimmy is;...
3642-1792-0150 (2C)
Does the "(2C)" sub for the ("2D)" ??...

Also , I noticed that in the 2nd pix from the left (& On the TV) the letters "ignal" appear center screen..
Does that vindicate the Main Board as being good ???
Or is the Tcon part bad ???
I'm trying to eliminate the LED Panel as bad , did you ???..

There are 2 fuses at the top left side of the board & they are both good...(FP1 & FP2)


THANKS...



Later...Ron.M......

[budm]

Re: Vizio E420i-AO No pix NO sound & NO Menu !!!

That means the T-CON is getting signal and able to send to the LCD panel to display so it is not dead T-CON. At this point I suspect something in the panel but not 100% sure.