Samsung UN65KU6300FXZA no picture

[eagle00799]

Re: Samsung UN65KU6300FXZA no picture

Budm I get nothing but a blue screen that flashes bright then dim then off then repeat. Disregard post 10 if you will, I tried getting some voltages but they are all over the place in accordance with the screen flashing on and off. The only stable voltage I can get is the Panel-3.3v on the main board test point and the 12.66v coming off the power supply but only if I disconnect the cable that connects to the main board, with the cable connected the reading is all over the place for the 12.66v.

[eagle00799]

Re: Samsung UN65KU6300FXZA no picture

Budwich, I already tried disconnecting the U connectors with no change at all.

[budm]

Re: Samsung UN65KU6300FXZA no picture

Budm I get nothing but a blue screen that flashes bright then dim then off then repeat. Disregard post 10 if you will, I tried getting some voltages but they are all over the place in accordance with the screen flashing on and off. The only stable voltage I can get is the Panel-3.3v on the main board test point and the 12.66v coming off the power supply but only if I disconnect the cable that connects to the main board, with the cable connected the reading is all over the place for the 12.66v.

Are you talking about the two ribbon cables from main board to the LCD panel?
I will wait to see the clear pictures of the main board so I can see the test points in the T-CON section of the main board.

[budwich]

Re: Samsung UN65KU6300FXZA no picture

Budwich, I already tried disconnecting the U connectors with no change at all.

no sure that observation is accurate... between what you posted at the start and the result of the test. As you can see in the other thread, the screen is different than when ALL things are connected up. Please post of a picture of the display result from either side of the disconnect.

[eagle00799]

Re: Samsung UN65KU6300FXZA no picture

budm the cable I referred to is the cable that connects the power supply to the main board.

[eagle00799]

Re: Samsung UN65KU6300FXZA no picture

i will try to get clear pics of the main board test points and pics of the screen with u connectors out.

[budm]

Re: Samsung UN65KU6300FXZA no picture

OK. I re-read you post #1 again.
The A13V is not steady when main board is connected, but if the main board is NOT connected the Voltage is steady, the backlights come on and stay on, but unstable when main board is connected.
With all the cables in place, when the TV is turned off, what Voltage do you get at A13V pin?
So the key point right now is to find out why the A13V is fluctuating when main board is connected to the power supply board.

[eagle00799]

Re: Samsung UN65KU6300FXZA no picture

Hope these pics work better, the 1st 2 pics are of the 2 testing points i could find on the main board. The next 4 pics are the main board in 4 sections. The next 3 are pics of the screen, 1st pic is with uconnectors in place, 2nd is with the left u connector out and the right side in place. 3rd pic is left u connector in place and right u connector out. The only difference i could see is no matter which u connector was out the horizontal lines on the bottom where gone.

[eagle00799]

Re: Samsung UN65KU6300FXZA no picture

Budm #27 that is correct

[budwich]

Re: Samsung UN65KU6300FXZA no picture

ok... that points / confirms to a significant problem away from the panel... which it appears is where you are headed.

[budm]

Re: Samsung UN65KU6300FXZA no picture

OK, I have to look at the pictures of the main board in details to give you the test points to test.

BTW, if both ribbon cables between main board and LCD panel are disconnected, is the A13V stable or it still goes up and down?

[budm]

Re: Samsung UN65KU6300FXZA no picture

https://www.badcaps.net/forum/attach...1&d=1597329104

What is that little black box next to the speaker with white sticker on top and connected to the main board?

[eagle00799]

Re: Samsung UN65KU6300FXZA no picture

that is the wifi box

[eagle00799]

Re: Samsung UN65KU6300FXZA no picture

ok after a 2nd check i realized i had VM set on ACv, on DCv i get 12.66v on the power supply with the cable connected to the MB but it drops to 9.4v and shoots back to 12.66v right before the lights come on. i get 3.3v at panel check point but the AVDD is all over the place, seems to be at 2.0mV and goes up but nowhere near the 1.7v it should get with everything hooked up.

[Diah]

Re: Samsung UN65KU6300FXZA no picture

when I disconnect the plug connecting the power supply to the main board the backlights come on and stay on, when I disconnect the ribbons on the main board one at a time it doesn't change the screen at all,

the 2 ribbon you call them...they are LVDS. disconnected them both from main boards side... then power on the tv.. check the back light remain on.... the audio optic socket led will lit red and remain red ?

[budm]

Re: Samsung UN65KU6300FXZA no picture

ok after a 2nd check i realized i had VM set on ACv, on DCv i get 12.66v on the power supply with the cable connected to the MB but it drops to 9.4v and shoots back to 12.66v right before the lights come on. i get 3.3v at panel check point but the AVDD is all over the place, seems to be at 2.0mV and goes up but nowhere near the 1.7v it should get with everything hooked up.

OK.
In standby mode the 13V will be about 9V to save energy but enough to keep the main board alive, when PS-ON is present it will jump back up to 13V.
So at this moment the 13V is steady, right?
The AVDD (about 15 ~ 20V) is generated by the boost converter on the T-CON circuit on the main board that converts 12V to high Voltage AVDD. We have to check and see if that T-CON circuit on the main board is getting 12VDC to run or not

[eagle00799]

Re: Samsung UN65KU6300FXZA no picture

with the LVDS disconnected at the MB, backlight comes on bright then dims then off, red optical led comes on at power on and stays on for a bit after the tv powers off then goes out, tv powers back on and repeats.

[eagle00799]

Re: Samsung UN65KU6300FXZA no picture

yes the 13v is steady, i couldn't tell if the AVDD says 1.7v or 17v on the board but i have seen flashes of up to 16v and OL.

[Diah]

Re: Samsung UN65KU6300FXZA no picture

with the LVDS disconnected at the MB, backlight comes on bright then dims then off, red optical led comes on at power on and stays on for a bit after the tv powers off then goes out, tv powers back on and repeats.

please upload photo high resolution on the back side of the main boards

[eagle00799]

Re: Samsung UN65KU6300FXZA no picture

Backside of main board