Sony KDL-50W685A horizontal black lines Pattern

[Raulnn]

good morning! I have a problem with this Sony. The image has a pattern of black horizontal lines, I attach a photo of the lines. The power supply is external and emits a sound. I don't think it's because of that. Let's see if someone can help me.

[nomoresonys]

Don't think the power supply should be noisy, did you check the dc output of it with a multimeter, just put one probe inside and the other on the outside.

[Raulnn]

Don't think the power supply should be noisy, did you check the dc output of it with a multimeter, just put one probe inside and the other on the outside.

Good afternoon! If I measure without connecting to the TV 4.86v

[PontyPCs]

Looks like a screen data line issue, locate the 8 data lines on the screen driver boards, and using cellotape isolate them, see if that cures the problem, works on most screens in various TVs

[nomoresonys]

Good afternoon! If I measure without connecting to the TV 4.86v

Looks like it's bad, 4.8, suppose to be 19.5, you might be able to repair it or just try a replacement power supply.

[Raulnn]

Looks like a screen data line issue, locate the 8 data lines on the screen driver boards, and using cellotape isolate them, see if that cures the problem, works on most screens in various TVs

I'm going to do that test, I think it's possible that you are right. but this model is complicated to do this test. It is difficult to access the main board, it is difficult to release the flex, and it does not have an independent tcon, it only has one flex. but I'm going to try. thank you

[Raulnn]

Looks like it's bad, 4.8, suppose to be 19.5, you might be able to repair it or just try a replacement power supply.

It could be bad, but I don't know if it can cause those lines. I am going to try what the other colleague says, and if not I will try to buy another external source. THX so much

[lotas]

The power supply cannot produce 4.8v, if it produced such a low voltage, the TV would not turn on at all, which means you are not measuring correctly or the multimeter is not working.

First, try carefully cleaning the LVDS connecting cable from the motherboard to the T-con (contacts) on both sides with isopropyl alcohol...

[nomoresonys]

The power supply is also not suppose to make any noise, so I wouldn't be so quick to rule it out. Make sure you are testing in dc mode, maybe test another power supply from something else and see what voltage you get.

[Raulnn]

The power supply cannot produce 4.8v, if it produced such a low voltage, the TV would not turn on at all, which means you are not measuring correctly or the multimeter is not working.

First, try carefully cleaning the LVDS connecting cable from the motherboard to the T-con (contacts) on both sides with isopropyl alcohol...

I'm going to start with the easiest thing, cleaning the flex. forgive my ignorance. how do you release it? I have never seen a flex like that. Thanks so much

[lotas]

Try to carefully move the black insert 2-3 mm on both sides with your fingernail.

[lotas]

Or press the white insert and gently pull the train towards you.
The main thing is not to damage the cable or connector!

[Raulnn]

The power supply cannot produce 4.8v, if it produced such a low voltage, the TV would not turn on at all, which means you are not measuring correctly or the multimeter is not working.

First, try carefully cleaning the LVDS connecting cable from the motherboard to the T-con (contacts) on both sides with isopropyl alcohol...

I update. I have cleaned the flex at both ends. It hasn't worked. In fact, yellow lines now appeared, some wider than others, until suddenly there was no image left.

Of course, I did a correct manipulation, everything turned off.

But I discovered something. The noise was not from the power supply, it came from the area of the controller boards, the area where the tcon is integrated. When the lines were no longer visible, and there was no image, the noise disappeared.

Could it be a coil in that area in poor condition that is causing the problem? Or could it be some tcon chip?


Thanks to all for the help.

[Raulnn]

I'm going to start with the easiest thing, cleaning the flex. forgive my ignorance. how do you release it? I have never seen a flex like that. Thanks so much

hello! could you help me? I don't see the control values for tcon, vgh and vdd. vgl yes I have seen it and it is correct. I don't know if Sony calls them by another name. The TV has TVon integrated into the panel controllers, with a single flex. It is difficult to do panel tests. Let's see if someone can help me continue. Thanks in advance

[Raulnn]

update! I think it's a Tcon problem. The problem is that the tcon is integrated. I would say that the problem is in the DC DC converter circuit. Also, when I connect the TV the integrated DC DC converter gets hot. How can I know if it is the DC DC converter or another element? I have not detected short circuits in nearby capacitors. Let's see if someone can help me diagnose the DC DC converter. I cannot replace the tcon because it is attached to the panel. thank you

[Diah]

you have damaged the LVDS...,, so how it come after cleaning it produced yellow line as you stated... use your mobile camera to focus on the contact pins

[Raulnn]

you have damaged the LVDS...,, so how it come after cleaning it produced yellow line as you stated... use your mobile camera to focus on the contact pins

Now nothing is seen on the screen, only backlight. I haven't been able to damage anything. I did everything following security measures
the pegs are fine

[Diah]

show here clear high resolution photo of both end lvds cable pins

[lotas]

Now nothing is seen on the screen, only backlight.

Check the fuse on the t-con and see if there is any voltage on the t-con.

[Raulnn]

show here clear high resolution photo of both end lvds cable pins