Samsung UN65H6203

[MadSand360Man]

Hi all I am new to this group, actually new to forums in general. I want to thank everyone in advance that might be willing to help me with this and also apologize if this is posted in the wrong spot. I picked up this TV earlier and the entire bottom half of the LED strips are not working, I tested them individually and some work so I am assuming this is a power issue? When i check the voltage on CNL802 I am getting 320V from pins 1,2,6,8, and 9. Pin 6 only registers 60V, could this be the problem? Is the power board definitely the reason why the bottom half won't light up. Sorry I can't provide more info, checking the pins is pretty much the extent of my knowledge here.

[dick_barton]

Re: Samsung UN65H6203

The leds are connected in series like fairy lights so you would need to replace the faulty leds in order for the whole strip to work. Or replace the strips completely if they are not to expensive.
Pin 4 = ??V

The information on the board says the leds run at 220V, 400mA

[MadSand360Man]

Re: Samsung UN65H6203

Hey thanks for the reply! Right so the board says they should be at 220 but are at 320 except for pin 4 which reads about 60V, If the whole row goes out when one led fails shouldn't the top half be completely out as well?

[Andrew F. Ali]

Re: Samsung UN65H6203

The leds are connected in series like fairy lights so you would need to replace the faulty leds in order for the whole strip to work. Or replace the strips completely if they are not to expensive.
Pin 4 = ??V

The information on the board says the leds run at 220V, 400mA

The LEDs on each strip is connected in series.....In some cases each strip is also connected in series......In your case each strip is connected in parallel.....therefore, you just need to change the strip that is not working......or you could use the 'Reeceyburger' method and stack a new LED in the old LED spot.

[dick_barton]

Re: Samsung UN65H6203

The 320V is a giveaway that there are led problems. If the 400mA was flowing through all the leds in the string then the voltage would be 220V or close to.

If a led is shorted then the voltage will still reach the next led in line. However this puts the remaining leds under strain and leads to an avalanche effect with more and more leds failing. If the led burnt out and went open circuit then power could not reach the next led in line so they would be unlit.
If you disconnect the led connector do both D1 and D2 spike at 320V

[MadSand360Man]

Re: Samsung UN65H6203

TV ON, LEDs PLUGGED IN, GROUNDED TO BOARD
1. D1+ 321.1V
2. D1+ 321.1V
3. NC N/A
4. D1- 236.5V
5. NC N/A
6. D2+ 321.1V
7. NC N/A
8. D2- 320.9V
9. D2- 320.9V

TV ON, LEDs UNPLUGGED, GROUNDED TO BOARD
1. D1+ 321.6V
2. D1+ 321.6V
3. NC N/A
4. D1- .260V
5. NC N/A
6. D2+ 321.6V
7. NC N/A
8. D2- 321.2
9. D2- 321.2

[Andrew F. Ali]

Re: Samsung UN65H6203

OK...so your problem is the backlights....You can strip the panel down to the backlights???

[MadSand360Man]

Re: Samsung UN65H6203

Hi, yes I already did this, as you can see in this pic the top half lights up (some are out) but the bottom half nothing, even though I tested each diode individually and some work on the bottom half. Are the diodes specific to my display or are they universal? Sorry if this has already been answered in another thread. Can anyone recommend a good place to buy just the diodes? thanks everyone who has responded.

[dskall]

Re: Samsung UN65H6203

Try this: http://alpengeist-tvrepair.blogspot....ces-tools.html

[budm]

Re: Samsung UN65H6203

TV ON, LEDs PLUGGED IN, GROUNDED TO BOARD
1. D1+ 321.1V
2. D1+ 321.1V
3. NC N/A
4. D1- 236.5V
5. NC N/A
6. D2+ 321.1V
7. NC N/A
8. D2- 320.9V
9. D2- 320.9V

TV ON, LEDs UNPLUGGED, GROUNDED TO BOARD
1. D1+ 321.6V
2. D1+ 321.6V
3. NC N/A
4. D1- .260V
5. NC N/A
6. D2+ 321.6V
7. NC N/A
8. D2- 321.2
9. D2- 321.2

You have two boost converter circuits, 2 PWM control MOSFETs; one for each set of LEDS.
D1+ (Anode of the LED string) is fed by one boost converter, D2+ is fed by another boost converter.
D1- is the Cathode return of the LED D1 string.
D2- is the Cathode return for the LED D2 string.
As you can see, something is not right due to what you show for the D2 Voltage reading.
D2+ is 321.2 Volt going to the Anode and the Return D2- is 321.2V which means the Vdrops (D2+ to D2-) on the D2 LED string is only 321.6 - 321.2 = 0.40V! That has to be measurement error or very low resistance between D2+ and D2-.
Recheck the measurement again, also check the resistance between D2+ and D2- terminal, also D2- and GND.

[MadSand360Man]

Re: Samsung UN65H6203

Hey dskall thanks so much! Is it safe to assume Samsung uses this diode across all their led tv models, meaning if I bought these they would definitely be compatible with mine?

[dskall]

Re: Samsung UN65H6203

Don't think anything is universal. You would need to remove one and check size, pad polarity, pad shape etc.

[budm]

Re: Samsung UN65H6203

His D2 Voltage readings do not making any sense.

[Andrew F. Ali]

Re: Samsung UN65H6203

His D2 Voltage readings do not making any sense.

Please re-check this as requested by budm.

[budm]

Re: Samsung UN65H6203

TV ON, LEDs PLUGGED IN, GROUNDED TO BOARD
1. D1+ 321.1V
2. D1+ 321.1V
3. NC N/A
4. D1- 236.5V
5. NC N/A
6. D2+ 321.1V
7. NC N/A
8. D2- 320.9V
9. D2- 320.9V

TV ON, LEDs UNPLUGGED, GROUNDED TO BOARD
1. D1+ 321.6V
2. D1+ 321.6V
3. NC N/A
4. D1- .260V
5. NC N/A
6. D2+ 321.6V
7. NC N/A
8. D2- 321.2
9. D2- 321.2

321.1 - 320.9 = 0.2V when plugged in also does not make sense.
321.2 on D- when unplug does not make sense since the return is open circuit when plug is removed.