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Samsung UN70NU6070FXZC not turn on,red light blink 2 times dark screen

My samsung TV UN70NU6070FXZC can't turn on, the red light blink 2 times with dark screen and no sound, and this cycle repeated after about 20 seconds again and again. The Tv reboot again and again. Have to unplug power cord to stop it.

Main board (BN94-14106C),

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Measurement points:

SW, PWOUT, HAVDD, AVDD, VGH, VGHD, FB_TRDY_3.

Power supply board (BN44-01016A)

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Driver boards (BN96-50136A) form left to right

Driver board 4 from up to down and from left to right

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Measurement points:

VCOM, XON, VGH, VSS, STV, CLR, LC1, LC2, CK1-8,

S1N0, S1P0, S2N0, S2P0, S3N0, S3P0,

TESTOUT0-COF1, TESTOUT0-COF2, TESTOUT0-COF3, TEST_EN,

TESTOUT1-COF1, TESTOUT1-COF2, TESTOUT1-COF3, TEST_MODE,

TESTOUT2-COF1, TESTOUT2-COF2, TESTOUT2-COF3,

TP112, TP113, TP114, TP115, TP116, TP117 (no on the rest of boards).

Driver board 2 from up to down and from left to right

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Measurement points:

VCOM, XON, VGH, VSS, STV, CLR, LC1, LC2, CK1-8,

S4N0, S4P0, S5N0, S5P0, S6N0, S6P0,

TESTOUT0-COF4, TESTOUT0-COF5, TESTOUT0-COF6, TEST_EN,

TESTOUT1-COF4, TESTOUT1-COF5, TESTOUT1-COF6, TEST_MODE,

TESTOUT2-COF4, TESTOUT2-COF5, TESTOUT2-COF6,

VH255, VH0, VL255, VL0, SRF, SFC (no on the board 4).

Driver board 1 from up to down and from left to right

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Measurement points:

VCOM, XON, VGH, VSS, STV, CLR, LC1, LC2, CK1-8,

S7N0, S7P0, S8N0, S8P0, S9N0, S9P0,

TESTOUT0-COF7, TESTOUT0-COF8, TESTOUT0-COF9, TEST_EN,

TESTOUT1-COF7, TESTOUT1-COF8, TESTOUT1-COF9, TEST_MODE,

TESTOUT2-COF7, TESTOUT2-COF8, TESTOUT2-COF9,

VH255, VH0, VL255, VL0, SRF, SFC (no on the board 4).

HAVDD, AVDD (no on the rest of boards).

Driver board 3 from up to down and from left to right

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Measurement points:

VCOM, XON, VGH, VSS, STV, CLR, LC1, LC2, CK1-8,

S10N0, S10P0, S11N0, S11P0, S12N0, S12P0,

TESTOUT0-COF10, TESTOUT0-COF11, TESTOUT0-COF12, TEST_EN,

TESTOUT1-COF10, TESTOUT1-COF11, TESTOUT1-COF12, TEST_MODE,

TESTOUT2-COF10, TESTOUT2-COF11, TESTOUT2-COF12,

VH255, VH0, VL255, VL0, SRF, SFC (no on the board 4).

 1. Disconnect main board from power supply board: plug power cord, backlight on, output=13v ch1=120v ch2=80v ok.

 2. Connect power board to main board disconnecting two connectors to panel, it can be turned on/off normally. No T-con board is found, is it included in the main board or side board?

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a. TV Standby: red light on, sound off, backlight off. on power board output=12v ch1=ch2=0v, on main board SW=0.1v PW=12vx2, HAVDD=AVDD=VGH=VGHD=0v FB_TRDY_3=0v.

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Measurement points: CH1, CH2, ON=12.35v, STB=11.5v,

b. TV On: red light off, sound on, backlight on, on power board: output=13v ch1=124v ch2=82v CNL801: +1=190v -1=+2=150v -2=+3=110v -3=66v +4=130v -4=+5=90v -5=+6=0v(this 2 pins are vacant?) -6=46v, on main board: SW=3.3v PW=13vx2, HAVDD=AVDD=VGH=0v FB_TRDY_3=0v VGHD=0.1v. It seems that video part of the main board is not working?

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Measurement points: SW, PWOUT, HAVDD, AVDD, VGH, FB_TRDY_3, VGHD,

 3. Only connect anyone of the two connectors from panel to main board connecting to power board, it can be turned on/off normally. It seems not to be possible. It is same if only disconnect anyone of the 1-4 screen connectors.

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a. TV Standby: red light on, sound off, backlight off, dark screen. on power board output=12v ch1=ch2=0v, main board SW=0.1v PW=12vx2, HAVDD=AVDD=VGH=VGHD=0v FB_TRDY_3=0v.

b. TV On: red light off, sound on, backlight on, dark screen. on power board: output=13v ch1=124v ch2=82v, CNL801: +1=190v -1=+2=150v -2=+3=110v -3=66v +4=130v -4=+5=90v -5=+6=0v(this 2 pins are vacant?) -6=46v, on main board: SW=3.3v PW=13vx2, HAVDD=AVDD=VGH=0v FB_TRDY_3=0v VGHD=0.1v. It seems that video part of the main board is not working too? Maybe both of left-screen and right-screen be faulty?

4. Connect both of the two screen connectors to main board connecting to power board, it can't be turned on/off normally. Dark screen, red light&sound&backlight blink 2 times for 2 seconds then all off. on power board output=13-12v ch1=115-105-0v ch2=77-70-0v(backlight: lightness-a little lightness-dark), CNL801: +1=190-280v -1=+2=150-250v -2=+3=110-210v -3=66v +4=130-160v -4=+5=90-130v -5=+6=0v(this 2 pins are vacant?) -6=46-90v, on main board SW=3.3-0.1v PW=13-12vx2, HAVDD=about 6-0v AVDD=about 10v-0v VGH=about 14v-0v VGHD=about 11-0v FB_TRDY_3=3.3v-0v (It seems that video part of the main board is working now?). And then after 20 seconds the cycle repeats again and again!! I had to unplug power cord to stop it.

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I replaced the main board and power board, nothing changed.

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Commenti:

@shawnfix post some good pictures of your boards with your question. Right now it sounds like it is your main board that is giving you problems. Use this guide Aggiungere immagini ad una domanda to add images to your question

da

@shawnfix since you already replaced both the power board and the main board without any change but "disconnecting two connectors to screen, it can be turned on/off normally" then the issue would be your screen (LCD driver board possible). This is definitely not a normal situation. When you wonder if "It seems that video part of the main board is working now?" you can't be sure of that since that would require an oscilloscope to check the waveforms not voltages. Post some pictures with your question so we can see your boards interconnect wiring etc.

da

@oldturkey03 Thank you very much! Sorry, I don't know the TV‘s work principle . I purchased a main board and a power board and replaced them, but nothing changed. Could the new main board be burned if the sreen has issue? I can't understand why the voltages of those points like VGH etc. on main board without connecting screen were 0v? Was the main board protected? Thanks!

da

@shawnfix That is where it gets confusing. Your voltages maybe going to 0V because the mainboard cannot find the display. It may not send the signal to the power board to turn it on. It is very unusual for a screen to shorten out the TV the way you describe. Those errors are usually from a bad main board.

Cable 1 and 2 connect to the LCD driver boards and the T-con circuitry is on the mainboard, so no separate T-con board.

da

1. As 3-b above, the mainboard is on with sound(TV audio), backlight and 3.3v &13v from power board, So the mainboard turns off those voltages because it cannot find the display, right?

2. As 4 above, Tv had been turned on for 2 seconds with all voltages(can't be mesured exactly because of very fast changing) and backlight and sound and only no display, but TV was turned off instantly again and can't stay on standby and reboot after 30 second.

Do you think that 2 power board are ok and the mainboard I just purchased are bad too? I have to return the mainboard.

da

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Hi @shawnfix,

Just eliminating things as @oldturkey03 suggests, it sounding like the mainboard

If the tcon board is a BN96-50030A, check if there is also 12V being supplied to it when the TV is turned on.

Here’s an image to show where to look.

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(click on image to enlarge for better viewing)

If it is a different tcon board, mostly there is a fuse similarly located, near the cable connector for the mainboard cable. The power comes through the mainboard and not direct from the power board.

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Hi Jayeff,

Thank you so much for reply!

No any T-con board and fuse is found, is it included in the main board or side board?

da

@shawnfix

it will be on the mainboard if there are two cables going from it to the screen.

Strange that there is no tcon board as I Googled the "TV model number +tcon" and got results as posted.

If there is a separate tcon board then usually the mainboard connects to tcon via 1 cable and then the tcon connects to the screen via 2 cables as shown in the left side image above

da

@jayeff the model that @shawnfix has appears to have a mainboard with integrated T-con board. Both LVDS cables connect from main board to the LCD driver boards. I wonder.....@shawnfix post some good pictures of the boards on top of the panel. The boards where the two ribbon cables connect to.

da

@oldturkey03 @shawnfix

My mistake ;-(

I found this and since there was no image I looked for the board number as shown and found an image of that which I posted

da

@jayeff @shawnfix I wonder if the boards where cable 1 and 2 connect to are the issue. What exactly happens when you disconnect those two cable on the board on top of your screen (not on the main board)? Do not take any measurements, just let us know if the behavior stops and returns to normal on/off etc.

The boards have the TAB connection to the panel so that will definitely make them the driver boards but I wonder if those are not the issue since powerboards and main board have already been replaced.

da

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Shawn sarà eternamente grato.
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