LG 65UH5500 Royally Scroo'ed, I Think.. :(

[Michale32086]

Well, the LG 65UH5500 has rear'ed it's ugly borken head again..

Details on the original problem here..

https://www.badcaps.net/forum/showthread.php?t=69687

Anyways, came into the shop this morning.. Turned on the LG and the backlights came on high intensity for a second, then settled down to normal..

NOTHING on the screen but backlit blackness.. No LG logo, no display, no nuttin..

Cracked it open, replaced the MAIN board with a known good one.. Still the same problem...

OK, so I am thinking TCON board. Not good, but not the end of the world..

I take off the wide TCON connectors one at a time.. With the left one off (red) the display comes on and displays everything fine but on the right half of the screen... OK, that seems to confirm the TCON is the issue..

With an impending sense of doom, notice the cellophane board to board connector on the left (green)..

I reconnect the TCON connector and disconnect the board to board connector (green)....

Power up the TV... Frak!!! I get a picture on the right 3/4ths of the TV....

So, that would seem to indicate that the board (blue) is bad.. And I am fairly certain that THAT can't be repaired/replaced...

If I totally gank'ed here???

[Michale32086]

Re: LG 65UH5500 Royally Scroo'ed, I Think..

Couple things to note..

First off, the initial bright intensity does not appear to be a function of the backlights.. When powering up and looking at the TV from the back with the case off, the LEDs are no brighter at initial power up than they are normally.. This leads me to believe that the white intensity is a function of the panel and not the backlights. Dunno what that means, but there it is..

Also, you will note in the attached pic that even though I have a 3/4 picture on the display, the side closed to the white area on the right side is darker than the half pic on the left side..

This gives me some hope that it may be the TCON after all..

[budwich]

Re: LG 65UH5500 Royally Scroo'ed, I Think..

well you played with this set quite a lot. Odds are perhaps the side tabs on the trouble side have an issue. Have you checked them. Your "test" of disconnecting the "coupling cable" basically isolated that troubled section allowing the display for the rest of the set to function. IF its not a smd component failure in / around that section of edge board, then you check the side tabs. Depending on what the issue is, you might be able to pull the tabs and still a functioning set.

[Michale32086]

Re: LG 65UH5500 Royally Scroo'ed, I Think..

well you played with this set quite a lot. Odds are perhaps the side tabs on the trouble side have an issue. Have you checked them. Your "test" of disconnecting the "coupling cable" basically isolated that troubled section allowing the display for the rest of the set to function. IF its not a smd component failure in / around that section of edge board, then you check the side tabs. Depending on what the issue is, you might be able to pull the tabs and still a functioning set.

I'll give that a shot.. Thanx...

[Michale32086]

Re: LG 65UH5500 Royally Scroo'ed, I Think..

Just to clarify.. Should I pull the tabs on the side that is messed up?? Or the other side???

[budwich]

Re: LG 65UH5500 Royally Scroo'ed, I Think..

The side that is messed up is messed up for a reason.... that reason could be tab related OR smd component on the bottom edge board that "feeds" the side tabs. You might find that smd component (bad cap or resistor) and replace it and have a totally good set (basically "brand new"). If you pull the tabs, the set MIGHT be ok but its operation is "slightly compromised". Based on your pictures, it appears that it is more likely a component issue since there doesn't appear to be any "lining" and such indicating a faulty tab. Hence, IF it is some sort of "shorting issue" in the edge board, pulling the tab may not work... it depends on why the thing "shuts down" / "fails to start"... ie. over current drawn, voltage drop, etc.

[Michale32086]

Re: LG 65UH5500 Royally Scroo'ed, I Think..

Well, on the PLUS side, the picture is more uniform... Pulling the tabs DID get rid of the darkers side...

On the down side, it did not fix the main problem. I still have to disconnect the one board to get any kind of pic.. There are also some thin vertical lines on the far right of the display panel.. I am assuming that is more indication that that one board is bad??

[budwich]

Re: LG 65UH5500 Royally Scroo'ed, I Think..

:-( IF there was no edge boards on the side of the set (ie. just tabs), the last tab at the bottom is responsible for delivering "stuff" to the side tabs via "panel tracks". It would appear that is has "source tab issues" based on the vertical lines. Could even be a contamination issue from water in the area... did you check that section of the edge board / solder tracks. Anyways, as I pointed out, pulling the tabs might not solve your problem. By pulling them, you have reduced the load on the ones on the other side so the "darkness" is gone, but the issue still remains in and around the source tab / edge board at the bottom corner.

[Michale32086]

Re: LG 65UH5500 Royally Scroo'ed, I Think..

:-( IF there was no edge boards on the side of the set (ie. just tabs), the last tab at the bottom is responsible for delivering "stuff" to the side tabs via "panel tracks".

Yea, there was no edge boards.. It was just small tabs..

It would appear that is has "source tab issues" based on the vertical lines. Could even be a contamination issue from water in the area...

Yea, that would be my guess.. My shop is an outdoor (but covered and walled) area and humidity was horrendous overnight..

did you check that section of the edge board / solder tracks. Anyways, as I pointed out, pulling the tabs might not solve your problem. By pulling them, you have reduced the load on the ones on the other side so the "darkness" is gone, but the issue still remains in and around the source tab / edge board at the bottom corner.

Yea, I did a visual and didn't really see anything that stands out..

I am thinking that, due to the high humidity, moisture developed and, when I powered up the TV, something got fried...

Attached are pics of the board area..

[budwich]

Re: LG 65UH5500 Royally Scroo'ed, I Think..

unlikely that "air humidity" would have "root caused" where you are at. More likely, that source tab was an issue to start but with everything connected, the draw was too great and the tv wouldn't start. Once you disconnecting the interconnection cable, you reduced the feed to the trouble source tab but also to the side driver tabs. However, it that mode, you can't / won't see the issue with source tab as it isn't being driven. Once you removed the side tab, you thenare able to drive the source tab again and it would appear there is a problem with it. Further note, you are only looking at the "back side" of the source driver at the edge board, but it is possible to have an issue at the panel side in terms of contacts possibly.

[Michale32086]

Re: LG 65UH5500 Royally Scroo'ed, I Think..

unlikely that "air humidity" would have "root caused" where you are at.

Can't tell you how glad I am to hear that..

Further note, you are only looking at the "back side" of the source driver at the edge board, but it is possible to have an issue at the panel side in terms of contacts possibly.

If there is a contact issue at the panel side, can that be fixed??

[Michale32086]

Re: LG 65UH5500 Royally Scroo'ed, I Think..

Think I found the culprit...

[Moreno83]

Re: LG 65UH5500 Royally Scroo'ed, I Think..

Hmz , you indeed found the problem but how did that happen?

Not fixable unless you got a bonding machine......

[mmartell]

Re: LG 65UH5500 Royally Scroo'ed, I Think..

Looks like it burned up and melted.

[Michale32086]

Re: LG 65UH5500 Royally Scroo'ed, I Think..

Hmz , you indeed found the problem but how did that happen?

Not fixable unless you got a bonding machine......

A "bonding machine"??

Do tell.....

[Wilderone]

Re: LG 65UH5500 Royally Scroo'ed, I Think..

A "bonding machine"??

Do tell.....

Not cheap equipment..

https://m.youtube.com/watch?v=faHnLqrlL3o

[Michale32086]

Re: LG 65UH5500 Royally Scroo'ed, I Think..

ACK! I see that..

[angelos]

Re: LG 65UH5500 Royally Scroo'ed, I Think..

Now you're talking big money. Apparently in my country this machine is not allowed to enter the country via customs. They made an agreement with Samsung Electronics to prevent the importing of equipment used in repairing LCD panels. Clever hey?

[budwich]

Re: LG 65UH5500 Royally Scroo'ed, I Think..

IF you are lucky, and since the "trace" appears to be on the "end of the ribbon", you might find a way to connect a thin wire from the corresponding endpoint with some form of soldering at the board side and maybe some conductive glue at the panel trace (if you can locate it with out disturbing the tab bond area).... since the panel isn't basically any good at this point. Of course, its your time spent.... but it is an "outside possibility".

[Michale32086]

Re: LG 65UH5500 Royally Scroo'ed, I Think..

IF you are lucky, and since the "trace" appears to be on the "end of the ribbon", you might find a way to connect a thin wire from the corresponding endpoint with some form of soldering at the board side and maybe some conductive glue at the panel trace (if you can locate it with out disturbing the tab bond area).... since the panel isn't basically any good at this point. Of course, its your time spent.... but it is an "outside possibility".

Hmmmm Interesting..

Conductive glue, eh???