Insignia NS-50D40SNA14

[Helisstra]

Hello guys,

Situation :

The top left of the TV started to do fading horizontal lines. It's like the top third of the screen, and the lines were fading to normal reaching half the screens.
The horizontal lines were NOT black, they were a different tone of colour, but you were still able to see the image correctly.

After a couples of weeks like this, the screen went greyish/black. It's not the same colour as when the TV is off. Same issue on all Input.
The sound is still working perfectly on HDMI.
The backlight are all ON.
Cannot see the menu nor the splash screen on bootup.


What I have done / tested so far :

After lurking lots of forum, the symptom pointed out the T-Con board, since No picture, but Sound and Backlight are OK.
I have ordered a new T-Con and replaced it. Same issue.

The fuse F1 on both T-Con are ok.
I have 12 V after F1.

When I unplug either 2 of the ribbon cable or the T-Con main connector while the TV is on, it doesn't change anything. Doesn't flicker or anything.

When I press the channel button on the TV, the tone of grey/black seems to changed a bit.

The chip UL1 on the main power board is really hot to the touch. And the board is a bit darker around the chip than the rest.

No Capacitors looks burnt or damaged.


Whats Next ?


I would need your help for next step.
What should I measure with my multimeter?
What can be the issue? The main board?

Let me know thanks

[budm]

Re: Insignia NS-50D40SNA14

Is the T-CON mounted on the bottom center of the LCD PANEL?
Pictures of the whole back side of the TV showing all the boards will help.
What do you get on the screen if you have one ribbon cable between the T-CON and the LCD panel connected one at a time?

[Helisstra]

Re: Insignia NS-50D40SNA14

Here the picture of the full layout.
Yes T-Con in bottom middle


When I plug only the right ribbon, half right of the image is displayed correctly.
When I plug only the left ribbon, no image.
If I plug the right ribbon, on the left LCD, no image.
If I plug the left ribbon, on the right LCD, no image.
Plug back the right ribbon on the right LCD, half right image again.

I can do that right since both ribbon have the same P/N ?

[budm]

Re: Insignia NS-50D40SNA14

Here the picture of the full layout.
Yes T-Con in bottom middle


When I plug only the right ribbon, half right of the image is displayed correctly.
When I plug only the left ribbon, no image.
If I plug the right ribbon, on the left LCD, no image.
If I plug the left ribbon, on the right LCD, no image.
Plug back the right ribbon on the right LCD, half right image again.

I can do that right since both ribbon have the same P/N ?

You have problem in the LCD panel. This LCD panel has tab bonding board on the bottom edge of the screen so when people spray the cleaner on to the screen the liquid will drip down on to the board and damage the board, that is more likely to cause of the failure, but if you lucky, it can also be bad caps on the tab bonding board. The bottom line is that you will have to get the frame off the panel to inspect the board for damages.

[CapLeaker]

Re: Insignia NS-50D40SNA14

what budm said x 2

[Helisstra]

Re: Insignia NS-50D40SNA14

You have problem in the LCD panel. This LCD panel has tab bonding board on the bottom edge of the screen so when people spray the cleaner on to the screen the liquid will drip down on to the board and damage the board, that is more likely to cause of the failure, but if you lucky, it can also be bad caps on the tab bonding board. The bottom line is that you will have to get the frame off the panel to inspect the board for damages.

Thanks I will remove the frame, later today or tomorrow to inspect the board.

[Helisstra]

Re: Insignia NS-50D40SNA14

I have removed the frame, I don't see anything suspicious on the board. Linked picture

Is there a chance of repair at this point or it's dead since it's the LCD Panel ?

The bonding board is not replacable due to the soldered ribbon ?

[budm]

Re: Insignia NS-50D40SNA14

There are many caps on that tab bonding board, you should check to see if any of them show low (100 Ohms or less) resistance when measured between the two legs of each caps.

[Helisstra]

Re: Insignia NS-50D40SNA14

Tested them all, no one have 100 ohm or less.

[Helisstra]

Re: Insignia NS-50D40SNA14

Is there something else I can do about this issue or it's a case of buying a new TV ?

Let me know thanks