Samsung un70nu6900 power supply issue

[yankys]

HI, everyone needing a little help I have a 70 inc tv that has the turning on and back off issue. changed the main board no luck, checking the power supply and JP819 is only showing 4v i have 12.90 standby voltage can i assume that the power supply needs replacing. any help will be greatly appreciated.

[lotas]

Re: Samsung un70nu6900 power supply issue

You have to check that. And disconnect the cable that goes to the motherboard and plug it into a power outlet, the backlight should light up.

[yankys]

Re: Samsung un70nu6900 power supply issue

yes, and the back light comes on and stay on as long as the cable is disconnected from main board.

[lotas]

Re: Samsung un70nu6900 power supply issue

Well, it means the power supply is working, or you also purchased a non-working board, or you do not have a working panel.
Now try to connect it back to the motherboard, but disconnect the cables that go to the panel and check it will turn on from the remote control.

[yankys]

Re: Samsung un70nu6900 power supply issue

In the image your showing check jp821 to ground for voltage it shows 12.91.

[yankys]

Re: Samsung un70nu6900 power supply issue

With the cable to main board plugged in and the 2 ribbon cables unplugged tv will turn on with remote but turns off after a second or 2.

[lotas]

Re: Samsung un70nu6900 power supply issue

Nothing to worry about, no load (MB didn't start)

[yankys]

Re: Samsung un70nu6900 power supply issue

I'm not sure that I'm getting the 12v power on voltage.

[lotas]

Re: Samsung un70nu6900 power supply issue

Connect one at a time (first one cable, check, disconnect the first, connect the second and also check.

[lotas]

Re: Samsung un70nu6900 power supply issue

I'm not sure that I'm getting the 12v power on voltage.

You wrote above that you received 12.91v

[yankys]

Re: Samsung un70nu6900 power supply issue

yes, 12.91 at the jumper in the image you sent but not at pin 8 in the plug that go to the main board, and when I do the cables, it turns on with remote and back of with in a second unless I unplug the main power cable to the main board then it will stay on.

[lotas]

Re: Samsung un70nu6900 power supply issue

On 8 pin. should not be 12v, this is POWER ON (there is a signal to turn on the operating mode from the motherboard, and the jumpers are also connected to the 3-5-7-9 (12v) connector.

[yankys]

Re: Samsung un70nu6900 power supply issue

If voltage is 12.91 at the jumper shown in the image does this mean power supply is good.

[lotas]

Re: Samsung un70nu6900 power supply issue

Yes, if the unit were not working, then these 12.91v would not exist and the backlight would not light up.

[yankys]

Re: Samsung un70nu6900 power supply issue

what should i check to further diagnose this issue?

[lotas]

Re: Samsung un70nu6900 power supply issue

Try disconnecting these cables connecting the brackets, one at a time and with different motherboards (from your own and the one you bought).

[lotas]

Re: Samsung un70nu6900 power supply issue

In these models (NU series), the panels (the matrix itself) die very often.

[yankys]

Re: Samsung un70nu6900 power supply issue

with disconnecting these one at a time am I looking to see if the tv stays on?

[lotas]

Re: Samsung un70nu6900 power supply issue

Yes
Here is a video that can help determine the malfunction (and all the malfunctions of these models are panels).

https://www.youtube.com/watch?v=atNmhu7HMj0

https://www.youtube.com/watch?v=zGAVbMQrSek

[lotas]

Re: Samsung un70nu6900 power supply issue

And if possible, then disable the WI-FI module to check.