Weird smeary failure mode with Westinghouse LCD

[staze]

Hi All,

Have a weird failure mode that I would love some insight on. I figure it's gotta be the FRC or T-Con board, but I'm at a loss of how to actually fix without just randomly buying and replacing one of the two.

Here's a video of the issue. I've checked voltages, done visual inspections, reseated connections, tightened screws (incase of poor ground), tapped around on boards, connections, BGAs, etc.

Model is a Westinghouse WD55UB4530.

Any insight/assistance would be great. For reference, owner was just using the TV normally and when he went to the menu it did this. First stuff is the power on of the TV, then moving camera is me hitting the menu button.

https://www.dropbox.com/s/lc58pd0xt1...0Mode.mov?dl=0

[staze]

Re: Weird smeary failure mode with Westinghouse LCD

btw. Unplugging (either) half the connection from the t-con board to the panel results in no video at all. No idea if that's normal behavior... seemed odd to me. But then, I also don't see a horizontal drive connection at all... just vertical connections.

[aaronwt6]

Re: Weird smeary failure mode with Westinghouse LCD

That looks almost certainly like a panel failure to me.

[staze]

Re: Weird smeary failure mode with Westinghouse LCD

That looks almost certainly like a panel failure to me.

damn. =(

[arizanotlari]

Re: Weird smeary failure mode with Westinghouse LCD

Hello.

I repair this fault before. Change T-Con.

https://www.arizanotlari.com/2019/03...97-17mb98.html look first image

[CapLeaker]

Re: Weird smeary failure mode with Westinghouse LCD

press around on the tab bonds see if these lines change or go away.

[staze]

Re: Weird smeary failure mode with Westinghouse LCD

They do not. At least not flexing the intermediary pcb's between tcon and tab bonds.

[staze]

Re: Weird smeary failure mode with Westinghouse LCD

They do not. At least not flexing the intermediary pcb's between tcon and tab bonds.

Poked around the tabs and nothing. removed tcon and gave it some flexing. No change.

Any other input before I buy a t-con to test with?

[arizanotlari]

Re: Weird smeary failure mode with Westinghouse LCD

Dont buy t-con. i watch video again this is panel fault not t-con. Sorry for wrong advice.

[CapLeaker]

Re: Weird smeary failure mode with Westinghouse LCD

nah... it's junk. There was a chance for bad tab bonds, but if that didn't do anything, I'd part it out.

[staze]

Re: Weird smeary failure mode with Westinghouse LCD

Should I check the tab bonds on the panel itself? I haven't taken the whole back off since it's a nightmare of screws...

[budwich]

Re: Weird smeary failure mode with Westinghouse LCD

when you say you checked voltages... what voltages are you referring to? There are a number of voltages associated with the tcon that can be check and traced towards the edge board of the panel. Your posted picture doesn't give one a warm feeling but it is strange that disconnecting either side of the tcon doesn't give you any display... what does that mean? the display is total blank or there is still white portions?

[staze]

Re: Weird smeary failure mode with Westinghouse LCD

when you say you checked voltages... what voltages are you referring to? There are a number of voltages associated with the tcon that can be check and traced towards the edge board of the panel. Your posted picture doesn't give one a warm feeling but it is strange that disconnecting either side of the tcon doesn't give you any display... what does that mean? the display is total blank or there is still white portions?

Display is totally blank when disconnecting either "half" of the tcon->tab breakout boards (there's a single cable between FRC to t-con, then two cables out of t-con to long tab PCBs to each half of the panel). I too thought it was odd whole display is dead with half disconnected, but figured maybe the t-con was shutting down due to sensing a fault.

I've checked the primary voltages off the powersupply and traced them to the FRC board (12V, 5V, stb, etc).

I haven't broken out the scope and looked at them on the tcon. I don't see any obvious marked voltages on the t-con board. Attached are images of each of the boards...

[budwich]

Re: Weird smeary failure mode with Westinghouse LCD

hmmm... I see lots of voltages listed on the tcon card. You don't necessarily need a scope. They should be checked and listed with their label and value if you want the forum to help you get further. It may be fruitless but again it may give life back to 55in set.

the 125v / 5a fuse looks "scary"... was that checked?

[staze]

Re: Weird smeary failure mode with Westinghouse LCD

okay, I do see that on the connectors down to panel, is that what you mean? biggest issue is deciphering the labeling.

Will give it a look tonight.

[budwich]

Re: Weird smeary failure mode with Westinghouse LCD

NOTE: when you are tracing or trying to find where things travel, ensure that the set is unplugged and use your meter in resistance mode to check / trace tracks thru various "known" points in the board to areas of interest... you may not be able to see the exact tracking but are more interested in "end result"... ie. the same electrical connection.
Once you have determine them, then power up and meter the voltages at "standby" and at "turn on". Further, since you have "no display" when one or the other tcon to edge panel board cable is disconnected... also measure those same voltages then to see if you can spot some differences in the various "states". I am not thinking that your panel is bad at this point.

[staze]

Re: Weird smeary failure mode with Westinghouse LCD

Hey All,

I didn't forget. I went out and measured voltages, and everything seemed normal. Then a day or so later I went back out to give one last try and put pressure on the edges of the panel to see if maybe it was a loose bond. When I moved the TV out to be able to do the work, I turned it on and it came right up.

So, either sitting face down for weeks, or me just moving it caused the connection to come good.

I've told the client to be aware it'll likely fail again. But it does seem like it's probably a bad/poor bond to the panel itself rather than to the t-con or to the pcb's that link the tcon to the panel (not sure what those are called). =/

[RDC55]

Re: Weird smeary failure mode with Westinghouse LCD

I have a similar TV Model No.WE55UDT108 that has virtually the same failure as displayed in post 1 of this thread:

https://www.dropbox.com/s/lc58pd0xt1...0Mode.mov?dl=0

His failure eventually just went away, so before scrapping / parting I wanted to ask about some of the components on the panel CCA.

A flash memory (datasheet attached) - why might it be there and how would it be checked?

DK1, DK2, and DK3 6 pins device marked E5 any idea what they are?

[RDC55]

Re: Weird smeary failure mode with Westinghouse LCD

So no guesses on what these components are - DK1, DK2, and DK3 in attached pic?

[Davi.p]

Re: Weird smeary failure mode with Westinghouse LCD

pack TVS diodes i think.. i think them are 1,8v or 3,3v depends on which tension you haven on tcon.. can you post a picture of the defect? i can't see the video through the telephone..