samsung un46d6000 no picture

[budm]

Re: samsung un46d6000 no picture

What is the power supply board P/N? BN44-00423A?
If you at the board, there will Voltage chart printed on the board to tell you what the LED drive Voltage will be with load.

Test steps: no main board connected to the power supply board
1) Put LED connector back in place.
2) Keep Black probe on the chassis, Red probe on Top 1 +
3) Power up up the board while keeping your eyes on the mete to see how high the Voltage jumps up to before it settle down 10 seconds later, then remove power from the board.
4) Move red probe to Top 2 + and repeat step 3.
5) Do the same on Top 1 - and Top 2 -.
6) Report the results.

More likely to have open circuit in the LED string, LED strips are connected in series to form one large LED string.
Your bench power supply will not have enough Voltage to drive this large LED string.
LED tester: You can get LED tester similar to this for around $30 on EBAY.
https://www.shopjimmy.com/sid-gj2c-l...ght-tester.htm

[jasenpeters]

Re: samsung un46d6000 no picture

"What is the power supply board P/N? BN44-00423A?"

Yes, so I assume, the Power Board has a red dot next to:
PD46A1_BSM (BN44-00423A)

See Pic below:


I'll have test results soon...

[jasenpeters]

Re: samsung un46d6000 no picture

-- Voltages at Power Board Connector: CNL802 to LED Lights

Pin Label  Voltage (DC) to GND
--- ------ -------------------
          Pwr On 
       1st Peak 2nd Peak 3rd Peak
       -------- -------- --------
 7  TOP 2-  0.70    0.05
 5  TOP 2+  ~210    ~21   ~1.5
 3  TOP 1-  ~210    ~21   ~1.5
 1  TOP 1+  ~300    ~255

After the final peak, the voltages repeat.
All voltages are Positive with respect to GND
~ means approximately

I'm using a Fluke 73III Multimeter

[budm]

Re: samsung un46d6000 no picture

You have open circuit in the LED string, IE. LED failed open circuit, open circuit due to bad connector, open circuit wiring.

[jasenpeters]

Re: samsung un46d6000 no picture

Roger that...

Ok, I'll take the rest of the body apart and get to the LED strip(s)...
And work from there...

I suspect that if they are in series, one or more LED's are bad.
I doubt the actual connector to the Power Board or the wiring from the
Power Board to the LED strip, but I'll check.

Sounds good?

[jasenpeters]

Re: samsung un46d6000 no picture

I tested both Right and Left LED strips.

One of the LED panels is bad, as predicted.
Of, 36 LED, most were shorted, according to the Fluke continuity test.

The other panel, the good one, all LED's were tested.
From measurements of voltage and brightness of a single LED Light,
it seems that 2-2.5 volts can have a single LED light pretty bright.
That would be about 70-90 VDC or more to light 36 pairs in series.

For a strip, there is 2 parallel lines of 36 LED's in series.
Let me know if this makes sense.

Is it possible to power up the power board and have the "good" strip plugged in and light up as normal?
Or, do I have to have both strips (both being good) plugged in, for anything to light up?

Bad Strip: 2011SVS46_5K6K_H1B__1CH_PV_LEFT72

shopjimmy does not have one, any suggestions?

Thanks for any advice

[budm]

Re: samsung un46d6000 no picture

All the LED's are connected in series so what ever you do, all the LED strings have to be good LED strings to have all of them lighted up, the Vf of the LED will be around 3V at rated current, they typically drive these LED at or above max rated current so they failed.
When you get new strips make sure to turn down the backlights to as low as possible.

[Davi.p]

Re: samsung un46d6000 no picture

To troubleshoot is the mainboard...