Vertical lines, kdl-40lx900, i susect tcon

[Dogcatdog]

Re: Vertical lines, kdl-40lx900, i susect tcon

just tried that, with a hairdryer, held it about 5 mins around there it was a bit hot like almost to hot to touch with the backside of my index finger but not that hot.
i hope that was hot enough.
there was no change what so ever

thank you in advance

Ok apply some heat to ic303 and ic300 then test.

[Dogcatdog]

Re: Vertical lines, kdl-40lx900, i susect tcon

what else can i test?

[budwich]

Re: Vertical lines, kdl-40lx900, i susect tcon

have you checked the flat heat-sealed under the metal frame of the display?

OP, I don't think you ever responded to this suggestion. It might be worth you time to look. Something might be touching somewhere it shouldn't.

[Dogcatdog]

Re: Vertical lines, kdl-40lx900, i susect tcon

somehow i missed that, well i took it completely apart to the bondings and to check if the bonds are the problem, that took ages, but they are fine and dont have a problem at all, touching them applying pressure did not change anything at all in the picture. so i guess the problem is the t-con,or maybe the mainboard? i dont know how to make sure, the question remains what could be dead there and how to test it, i would like to fix it on the component level.

thank you very much in advance

OP, I don't think you ever responded to this suggestion. It might be worth you time to look. Something might be touching somewhere it shouldn't.

[Dogcatdog]

Re: Vertical lines, kdl-40lx900, i susect tcon

any other ideas?

[Dogcatdog]

Re: Vertical lines, kdl-40lx900, i susect tcon

there is a chip marked MAX17079 http://pdf1.alldatasheet.com/datashe...17079_10.html_ on the tcon, is that the gamma chip?

[Dogcatdog]

Re: Vertical lines, kdl-40lx900, i susect tcon

here are the Volt measurements i got for MAX17079
Pin 01. - 1.70V
Pin 02. - 0.00V
Pin 03. - 1.70V
Pin 04. - 0.00V
Pin 05. - 1.70V
Pin 06. - 0.00V
Pin 07. - 1.70V
Pin 08. - 0.00V
Pin 09. - 1.70V
Pin 10. - 0.00V
Pin 11. - 1.70V
Pin 12. to Pin 15 - 0.00V
Pin 16. - 5.94V
Pin 17. - 4.81V
Pin 18. to Pin 32 - 6.08V
Pin 33. - 0.00V
Pin 34. - 8.12V
Pin 35. - 7.39V
Pin 36. - 15.35V
Pin 37. - 0.00V
Pin 38. - 3.41V
Pin 39. - 3.26V
Pin 40. - 0.00V

[Dogcatdog]

Re: Vertical lines, kdl-40lx900, i susect tcon

hrmm seems like this is the Gamma chip, i could not find the datasheet, its MAX9697A https://www.maximintegrated.com/en/p...l/MAX9697.html i attached a picture with the measured voltages, since i dont know which is pin 1.
so this is the best i came up with.

thank you in advance

[Dogcatdog]

Re: Vertical lines, kdl-40lx900, i susect tcon

i wonder what the other chip then is the MAX17079, i mean its function

[Dogcatdog]

Re: Vertical lines, kdl-40lx900, i susect tcon

i found something.
there is an smd part marked, 33300 K028F,

When i try to measure the Voltage the pattern changes and or the screen goes black but im not sure if that thing
is the reason. it happens also when i push with my finger in that area, but only while i touch ground (chassis)
but same happens when i try to measure "capacitors/resistors"? around there
not sure what they are, cause there are no markings i will point them out in the picture

[freakaftr8]

Re: Vertical lines, kdl-40lx900, i susect tcon

You're pushing a small signal current into those test points changing the pattern on the screen from obviously varying the voltage to the main Sony processor. I would be under the assumption that either the main processor which is that big Sony CXD9982GG either has a bad BGA connection to the board or its bad itself. I would try to heat it up and see if the pattern changes at all.

And yes that Maxim chip is the gamma processor. Sharp likes to use those for their panels

[Dogcatdog]

Re: Vertical lines, kdl-40lx900, i susect tcon

so... shove it in the oven for like 5 mins at ca. 200 Celsius? or higher and or longer?

You're pushing a small signal current into those test points changing the pattern on the screen from obviously varying the voltage to the main Sony processor. I would be under the assumption that either the main processor which is that big Sony CXD9982GG either has a bad BGA connection to the board or its bad itself. I would try to heat it up and see if the pattern changes at all.

And yes that Maxim chip is the gamma processor. Sharp likes to use those for their panels

[freakaftr8]

Re: Vertical lines, kdl-40lx900, i susect tcon

well if you put enough time into it and you've got nothing left for it when I say go for it 450 degrees Fahrenheit for exactly 8 minutes. Then open the oven door turn the oven off let it cool for another 15 minutes before you touch it. And of course prop it up on something so the bottom of the board is not touching any metal surfaces

[Dogcatdog]

Re: Vertical lines, kdl-40lx900, i susect tcon

well i can set the oven for 230 Celsius which is 446 Fahrenheit will that do?
i can just set the temperature in 10C increments on my oven, so either 220C, 230C or if 230C is not enough then 240C which is then 464 Fahrenheit, and i can set the time for exact 8 mins. on my oven, more or less concerning question: there are some components on the bottom side, so i wonder wont those just fall off the board when i try to reflow the solder? or will the surface tension keeps those on the board?

thank you in advance

well if you put enough time into it and you've got nothing left for it when I say go for it 450 degrees Fahrenheit for exactly 8 minutes. Then open the oven door turn the oven off let it cool for another 15 minutes before you touch it. And of course prop it up on something so the bottom of the board is not touching any metal surfaces

[Dogcatdog]

Re: Vertical lines, kdl-40lx900, i susect tcon

ah one more thing, i can preheat the oven to the specific temperature, the question is should i shove the board in once the target temperature is reached,? or put it in from the beginning when i turn on the oven and let it get to 230C or 240C and then once it reached that, let it run for 8 mins, im asking because it takes a good 10 mins to reach the 230C i mean to preheat the oven. that would then mean the board is in for around 18 mins. so im not sure thats to long or not.

[jeffecor]

Re: Vertical lines, kdl-40lx900, i susect tcon

No heat the oven up first! Then 8 mins

[Dogcatdog]

Re: Vertical lines, kdl-40lx900, i susect tcon

so... shoved it in the oven for 8 mins. the tcon board, and thought well lets see, and well no change at all, then i thought, well lets try the mainboard, and hrmm still same no change at all in any kind, the symptoms are exactly the same, so i wonder, can it be caused by the power supply??? i cant imagine but who knows? what do you guys say? and if it is the SMPS what part of it could it be? what to test and what to test for?

[budwich]

Re: Vertical lines, kdl-40lx900, i susect tcon

You should try and trace the tracks going to and from the component in question. That might provide some clues (ie. are they going to grounds, power, interconnection to other ics, connection to resistors, etc?

[Dogcatdog]

Re: Vertical lines, kdl-40lx900, i susect tcon

which component are we talking about? "33300 K028F?" ? im not even sure what it is, i know that 2 terminals lead to ground of that and 2 lead somewhere into the processor since its a BGA i cant check where

You should try and trace the tracks going to and from the component in question. That might provide some clues (ie. are they going to grounds, power, interconnection to other ics, connection to resistors, etc?

[Dogcatdog]

Re: Vertical lines, kdl-40lx900, i susect tcon

btw. i am still not sure if the problem is from the tcon or on the mainboard, maybe somebody can help me to check the mainboard, somehow, there are schematics of the mainboard in the PDF from post #10 https://www.badcaps.net/forum/showpo...5&postcount=10 the actiual PDF> https://www.badcaps.net/forum/attach...8&d=1447079878 i dont really understand it and if it is even possible to test somehow