Sharp LC-60LE752E Panel shorted?

[mkkillah]

Hi all,


I got the "Sharp LC-60LE752E" edge lit. It had no backlight, no picture but it did have sound. Opened it up and measured backlight voltage leaving the P board: 80v which was too low. On the board it says: 117.8V. I measured all the main board voltages arriving from the Power board they were all fine.

Measured the voltage going into the T-con (12V). Test points that should be 6V were all 0 or 0.1v. At this point I was confused since both backlight and T-con weren't reading the voltages I expected.
I disconnected one ribbon leaving the T-con and it suddenly had picture + backlight (backlight measured 108.4v now). Only 1 side of the screen works (see picture).

At this point I feared for the LCD but I ordered a new T-con. It arrived, it didn't help, the backlight didn't turn on either with the new T-con. I decided to insert the t-con ribbon cable going to the LCD while the set was on. The screen flickered the T-con made a buzzing sound and 1 chip in particular got really hot (see picture). Unfortunately I wasn't able to check the bad side of the panel while I tried this since I had the TV flat on the table with only the good side sticking out.

I read up on the Sharp TV sets and people are pulling out the side driver boards. I opened it up myself and on the sides small ribbons with a chip on it are hanging out on their own not connected to anything except the LCD itself. One of these looks a little bit burned, on the bad side. When I push it while the set is on it will temporarily fix parts of the horizontal line on the good side. See the picture I attached.


Lost cause or will pulling out the side tabs (on the bad side) possibly fix the problem?
Based on these symptoms do you guys agree it's the panel that is shorted?

Greetings,
MK

[budwich]

Re: Sharp LC-60LE752E Panel shorted?

you have the "standard" failure in this area... bad tab drivers along one side of the panel. Lots of threads on this "condition". Basically, you need to remove the bonded tabs along the troubled side and the set will operate "normally" there after in most cases... although other faults may exist if your luck is unlucky... :-) Read up on a few threads as the operation is not "undoable" as once the tabs are removed, there is no way to put them back (ie. its a one time effort). Anyways, your set will likely be saveable.

[budwich]

Re: Sharp LC-60LE752E Panel shorted?

Further to help you determine if there are other issues with the set, on the side where you visibly saw the "hot driver", at the bottom corner of the panel, there is a flex ribbon cable that connects the drivers on that side to bottom edge boards of the panel. There is a cable clamping mechanism there that allows the flex cable to be disconnected just like those at the tcon. Disconnect the cable at the clamp (with power off of course). Look at the resulting display (all tcon cables connected). From this you should now see a full display which may have some issues. Depending on what the display looks like (input a known video test pattern from a dvd or computer file or what ever you have handy).... this will tell you if you have other issues.... before you go the last step of taking off the bonded tabs. Good luck.

[mkkillah]

Re: Sharp LC-60LE752E Panel shorted?

Disconnect the cable at the clamp (with power off of course).

I don't think my set has this board and the clamp connecting the two. Only the tabs. See the pictures I attached.

[budwich]

Re: Sharp LC-60LE752E Panel shorted?

have you compared both side? of course, sets do have differences but in general the side tabs need to get connection somewhere... that's what you are looking for.

[mkkillah]

Re: Sharp LC-60LE752E Panel shorted?

have you compared both side? of course, sets do have differences but in general the side tabs need to get connection somewhere... that's what you are looking for.

Yes, both sides are the same. I think the connection comes from within the glass. the leads arrive at a tab and continue after each tab.

[budwich]

Re: Sharp LC-60LE752E Panel shorted?

OK... you also can try disconnecting at the lower edge board. This isn't as good a test but it might help to make sure you are heading in the right direction. On the previous two pictures you posted, there is a "clampable flex cable" running / connecting the lower edge boards. You can unclamp that cable. The display will likely be more compromised, similar to disconnecting the tcon but because some of the lower drivers are still connected, the results may be better... plus you kind of still check out the remaining lower edge board.

[mkkillah]

Re: Sharp LC-60LE752E Panel shorted?

Thanks for the help so far. I'll unclamp the clamp shown in the pic. and post the results

[mkkillah]

Re: Sharp LC-60LE752E Panel shorted?

OK... you also can try disconnecting at the lower edge board.

I did and I got a result that looked a lot like the youtube video and the pictures I saw!

Maybe take the plunge and pull the tabs slowly?

[budwich]

Re: Sharp LC-60LE752E Panel shorted?

well, it would certainly appear that the "disconnected side" is your problem side.... kind of confirms your "eye and feel" of the heated driver chip. I think you are probably only left with removing the tabs on that side... ensure that they are "clean removals"... the tabs tear relatively easy but can leave "material" behind on the contact area that sometimes is an issue that needs further attention / careful cleaning.

[mkkillah]

Re: Sharp LC-60LE752E Panel shorted?

I can't believe this!

You guys are absolutely genius!!

THANKS budwich.

The side where the tabs were removed is a little blurry because the image is slightly displaced/ghosted.

[budwich]

Re: Sharp LC-60LE752E Panel shorted?

make sure that you can clearly see the contact area where the bonded tabs use to be... ie. nothing left / no residual material on the contacts..... but potentially, since the "design" is now somewhat compromised, there are some display issues that may result. Anyways, certainly better than the starting point.

One other thing... double check the flex ribbon that you disconnected between the lower edge boards to ensure that it has been re-seated properly as some when "playing" with these, have not put them back well... :-)

[budwich]

Re: Sharp LC-60LE752E Panel shorted?

One other question... can you post a picture of what you removed? Is it possible that you didn't remove (totally) what was needed?

[Moreno83]

Re: Sharp LC-60LE752E Panel shorted?

I think he removed the small tabs on either the left or right side of the panel. Only works on the DEFECTIVE side of the tv. You cant remove both sides , tv wont work anymore.
I have seen this before that removing those tabs fixes many panel problems.

I saw someone doing it while the tv was on , very cool to watch.

[mkkillah]

Re: Sharp LC-60LE752E Panel shorted?

make sure that you can clearly see the contact area where the bonded tabs use to be... ie. nothing left / no residual material on the contacts

Did all of that.

One other question... can you post a picture of what you removed? Is it possible that you didn't remove (totally) what was needed?

I removed the tabs on the defective side as there was no board attached. see my picture. Only 1 has a tear and I got that little bit off as well.

I think he removed the small tabs on either the left or right side of the panel. Only works on the DEFECTIVE side of the tv. You cant remove both sides , tv wont work anymore.
I have seen this before that removing those tabs fixes many panel problems.

I saw someone doing it while the tv was on , very cool to watch.

Yes I did.


I discovered the most curious thing. If I move my thumb over the area where the tabs used to be the TV does suddenly become sharp in that area. If I however do the same with something over my thumb like some tape it doesnt work anymore. Pressure is not the answer since it doesn't work with tape and doing this on any other place will do nothing. Only works if I move my thumb over the place where it used to be connected. Check the video: https://www.youtube.com/watch?v=IwzVZifXOD8

[budwich]

Re: Sharp LC-60LE752E Panel shorted?

Interesting.... good observation / find. Likely "story" is that you are providing a bit of capacitance which is impacting the "response" on the lines. Not sure what to suggest but there maybe some materials that have a bit of capacitance... maybe something like an ipad touch pen or equivalent material.

[mkkillah]

Re: Sharp LC-60LE752E Panel shorted?

Interesting.... good observation / find. Likely "story" is that you are providing a bit of capacitance which is impacting the "response" on the lines. Not sure what to suggest but there maybe some materials that have a bit of capacitance... maybe something like an ipad touch pen or equivalent material.

If I wet my finger it works even better. I don't have an ipad stylus and those things are still dependent on the connection with the human body right?

I am searching on google but didn't find anything yet.

[Moreno83]

Re: Sharp LC-60LE752E Panel shorted?

It is probably reacting to static electricity or some kind of magnetic field. Maybe put something between the bezel and the tabs , something that transports the electricity. Hard to explain in english.

Im talking about the same material that was under the mainboards from older samsung/LG lcd tv's. You often see it in tv's between panel and bezel for example.
It has to do with static electricity i think......

Cant find a picture

[mkkillah]

Re: Sharp LC-60LE752E Panel shorted?

It is probably reacting to static electricity or some kind of magnetic field. Maybe put something between the bezel and the tabs , something that transports the electricity. Hard to explain in english.

Im talking about the same material that was under the mainboards from older samsung/LG lcd tv's. You often see it in tv's between panel and bezel for example.
It has to do with static electricity i think......

Cant find a picture

I have no idea which material you mean but if you or anyone else can show me where to get it or at least what the name is I would be happy to try.

If I am going to be able to fix this last bit of the TV I'd be ecstatic!

[budwich]

Re: Sharp LC-60LE752E Panel shorted?

It is unlikely to be a magnetic "helper".... as I don't think your body / thumb is magnetic. Anyways, I would suggest you try fashion some sort of "ribbon capacitance". Try some double sided tape or maybe some mylar tape. Place it over the contacts. Make sure it is wider than the "next step"... get some aluminum foil and place it over the tape ensuring that NO aluminum is extending past the tape... you don't want any conductive material on the contacts. You also then try a second layer... tape and more foil.... almost like a capacitor.