Strange problem with Sony XBR-85X850G 85" LED tv

[mitsu2k]

Re: Strange problem with Sony XBR-85X850G 85" LED tv

Davi.p, is there any method you know of to try and guess the possibly bad protection diode before I start removing one by one? What about freeze spray? I did try and get a temerature reading using infrared thermometer but I could not get any readings that seemed abnormally hot.

[petehall347]

Re: Strange problem with Sony XBR-85X850G 85" LED tv

if they are tvs diodes the fail is shorted . look up the datasheet pinouts and look for shorts . semiconductors have a habit of failing short .

[Davi.p]

Re: Strange problem with Sony XBR-85X850G 85" LED tv

already said.. the problem them eventually get short under tension so you can't test them with MM, the only test that turns in mind is to heat them one per test with soldering stick then test if image is fully ruined at power on..

[mitsu2k]

Re: Strange problem with Sony XBR-85X850G 85" LED tv

already said.. the problem them eventually get short under tension so you can't test them with MM, the only test that turns in mind is to heat them one per test with soldering stick then test if image is fully ruined at power on..

Now I understand what you are saying. Your are saying that the fail possibly is dynamic and only fails under load. So yes in this case it would be impossible to test with mm. The screen looks perfect for the first 1 or 2 seconds after powering on. But then the lines appear. So you are correct, the problem is dynamic. I am just so afraid of causing other damage while trying to remove them. The tv is very large and the panel boards sit at an angle so it is very difficult to get the proper angle. I do have a hot air station but that may be to risky die to the proximity of the ribbon cable connector. I will have to shield it very well. The blob of solder method may work but due to the angle of the board, I'm afraid solder will just run down the board. I will keep thinking of a good method.

Question, should the tv still work with those diodes removed?

[Davi.p]

Re: Strange problem with Sony XBR-85X850G 85" LED tv

the tv uses the diodes only in a case of over voltage so for a test aren't necessary, but must be populated next soonest possible. I have never done this procedure, i can only try to suggest you the smallest nozzle and the lowest possible air pressure with high temperature cause the diode packs are ultra small, you need a decent air station, some skill, good eyes, steady hand, a decent plier for smd works, no expensive things to be clear..
If you have a cutter with brand new blade you can try detach it by small pressure..

[zomi]

Re: Strange problem with Sony XBR-85X850G 85" LED tv

You can try flux and retouch them with leaded solder
will make it easier to remove then.

[zomi]

Re: Strange problem with Sony XBR-85X850G 85" LED tv

Also kapton or similar heat resistant tape on the plastic connector

[Davi.p]

Re: Strange problem with Sony XBR-85X850G 85" LED tv

aluminum tape/foil is better

[zomi]

Re: Strange problem with Sony XBR-85X850G 85" LED tv

@davi.p would appreciate your advice on my thread https://www.badcaps.net/forum/showthread.php?t=114225
I have a similar issue maybe ?