No Picture. Backlight and Sound Work

Question

Hisense Television

Repair documentation and service information for Hisense televisions.

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BBM2C @bbm2c

Rep: 25

4

Gepost: 17 okt. 2022

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No Picture. Backlight and Sound Work

Hisence 65U6G

I have ordered all of the boards in a kit from shopjimmy however while swapping left and right T-Con output cables I noticed one had a burned trace. I flipped the cable end for end and it burned another trace on the same connector PIN number.

I have now also ordered new 60 pin cables.

My concern is I can not determine if the problem is with the panel, T-Con, or something upstream of the T-Con board.

Maybe someone can help with a schematic? The T-Con part number is 290410.

I really hate firing the parts cannon without a clear target.

Thanks,

Bill

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Ja Nee

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@bbmc don't connect your display but can you measure the VDC on VGH AND VDDA. Test Points are be just center right on your right connector. Voltmeter set to DC at about a 50V range Black to ground and Red to testpoint. Do the same with VCOM on the other connector side

17 okt. 2022 door oldturkey03

[image|2759791][image|2759790]

Thanks for the quick reply.

When I removed the shorted cable from the right output of the T-Con board I got a picture on the left side of the display.
You can see at the tip of the red arrow burn marks on the chassis. I do not see any physical damage to any of the boards popped caps, blown smds, etc. I'm flying blind without a schematic.

My hope is that the problem is upstream of the panel. If so I should be good firing the parts cannon. Worst case I'm out $125 in cannon fodder.

17 okt. 2022 door BBM2C

@oldturkey03

Thanks again!

I measured 19.40 VDC at both test points.

EDIT: and 8.21 VDC at VCOM

17 okt. 2022 door BBM2C

Ok that is the voltage to the Panel and the common to the board. Nothing spectacular. Darn, I hope it's the cable/board. The driver boards on the panel look okay? Anything scorched etc. that you can see? Careful you don't pull the ribbon cables off the LCD panel.

Did the Kit have the T-con board with it? You still have the old one?

17 okt. 2022 door oldturkey03

@oldturkey03

The kit includes every board. Power, Main, Driver, T-Con, and WiFi plus I ordered two new cables that connect T-Con to panel.

As I noted above I do not see any damage to any of the boards.

(Edit: There is some surface rust on the RG6 connector shield).

I did notice the 18 volt rail on the PS board to main board measured 16.6 vdc.

I'll add hi-rez pics of the boards to the original post.

Thanks,

-BB

18 okt. 2022 door BBM2C

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BBM2C @bbm2c

Rep: 25

4

Gepost: 21 okt. 2022

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Bad news for me.

I have replaced everything except the display.

Powered it up and had a full picture for a couple of minutes.

Unfortunately the picture faded away to be replaced by a white screen.

I disconnected the left T-con to display ribbon cable and have a perfect picture on the right 1/2.

I think at this point it is safe to assume the left display is bad.

With that I've reached the end.

Thanks @oldturkey03 for your time.

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Ja Nee

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@bbmc don't connect your display but can you measure the VDC on VGH AND VDDA. Test Points are be just center right on your right connector. Voltmeter set to DC at about a 50V range Black to ground and Red to testpoint. Do the same with VCOM on the other connector side — oldturkey03
[image|2759791][image|2759790]

Thanks for the quick reply.

When I removed the shorted cable from the right output of the T-Con board I got a picture on the left side of the display.
You can see at the tip of the red arrow burn marks on the chassis. I do not see any physical damage to any of the boards popped caps, blown smds, etc. I'm flying blind without a schematic.

My hope is that the problem is upstream of the panel. If so I should be good firing the parts cannon. Worst case I'm out $125 in cannon fodder. — BBM2C
@oldturkey03

Thanks again!

I measured 19.40 VDC at both test points.

EDIT: and 8.21 VDC at VCOM — BBM2C
Ok that is the voltage to the Panel and the common to the board. Nothing spectacular. Darn, I hope it's the cable/board. The driver boards on the panel look okay? Anything scorched etc. that you can see? Careful you don't pull the ribbon cables off the LCD panel.

Did the Kit have the T-con board with it? You still have the old one? — oldturkey03
@oldturkey03

The kit includes every board. Power, Main, Driver, T-Con, and WiFi plus I ordered two new cables that connect T-Con to panel.

As I noted above I do not see any damage to any of the boards.

(Edit: There is some surface rust on the RG6 connector shield).

I did notice the 18 volt rail on the PS board to main board measured 16.6 vdc.

I'll add hi-rez pics of the boards to the original post.

Thanks,

-BB — BBM2C

oldturkey03 @oldturkey03 Rep: 782,2k 1,1k 893 2,3k · Answer 1 · 2022-10-17T14:29:33-07:00

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oldturkey03 @oldturkey03

Rep: 782,2k

1,1k

893

2,3k

Gepost: 17 okt. 2022

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@bbm2c this is very difficult to determine. You are doing the right thing by replacing the T-con board as well as the cables. Sometimes flipping them can actually cause more issues. Anyhow, you are more likely having issues with the T-con board vs the panel. Since the LCD driver board(s) seldom are the cause but often the result of a short circuit. It might help if you try and get us some pictures of those boards. That way we can see what you see. Somebody may see something....Adding images to an existing question - iFixit Repair Guide

Schematics are pretty much non-existent in the public domain. So, we are on our own trying to fix this.

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Hisense Television

No Picture. Backlight and Sound Work

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