Samsung UE32UH4003

[claudiuandrei2010]

I have sound but no backlight, I put the led of my smartphone in the front of the Tv and I imagine on the tv so T-con it's fine and also I checked with 12V the led for the backlight and they are fine. I checked the voltage, the cable which goes to the main board, I have 5.2 on the pins and 0 on the other 5 pins. The cable which goes to the backlight has really small voltage 0.03.
I need some suggestions, either the power supply or main board but I don't know what to check the discovered where is exactly the problem.

[tvtimmy]

Re: Samsung UE32UH4003

unplug tv. then unplug cable going to mainboard to power supply. plug tv back in and check if the backlights come on. if they do the mainboard is bad. you have sound so you may have bad leds.

[claudiuandrei2010]

Re: Samsung UE32UH4003

I have not backlight, so it's a problem with power supply, what should I check on the power supply?

[tvtimmy]

Re: Samsung UE32UH4003

watch this video on what to check. it is on youtube.

Samsung UN32EH4003FXZA LED TV No Backlights How to Test Voltages for Power Supply and LEDsYouTube app - 1 year ago

[budm]

Re: Samsung UE32UH4003

You need to report the DC Voltage readings of all 4 pins of the LED connector with ref. to the chassis GND. LED coonector must be in place.
1) Leave Red probe on one of pin of the LED connector, then turn on the TV while looking at the meter to see how high the Voltage goes up to, then wait 5 seconds to see how low the Voltage goes down to. Turn off the TV.
2) Do the same test with the other 3 pins and then report the reading to us. More likely to have bad LEDs.

[claudiuandrei2010]

Re: Samsung UE32UH4003

1 D+
2 S-
3 NC
4 S-
5 D+

First teste
pin 1 0 voltage

Second test
pin2 0.011
pin 4 0.001
pin 5 0.002

I touched by a mistake pin 1 and pin 2 at the same with the red probe and the backlight turned on for 2 seconds. I was curious and I did it again and I saw a spike light on the display for a millisecond every 3 seconds.

[budm]

Re: Samsung UE32UH4003

You did the test with all the boards connected, right?

[claudiuandrei2010]

Re: Samsung UE32UH4003

Not, here is the right test

pin 1 0 0
pin 2 high 3.1 0.3
pin 4 4 V 0.3V
pin 5 5V 0.1

[budm]

Re: Samsung UE32UH4003

The power supply/LED driver board board is BN44-00664A.
All the boards connected then check the DC Voltage between GND and the the Cathode of DM805C. If you get no Voltage then you need to resolder all the pins of that power transformer TM801CS.
Pictures provided by shojimmy.

[claudiuandrei2010]

Re: Samsung UE32UH4003

I think my multimeter sucks, I changed from auto range to mV and I measured high voltage, now If I measured the voltage over 30V my Voltcraft 830 shows me "warning", in the manual of the multimer when that pops up there is a mistake with the lines. I suppose I blow up the fuse for low voltage.
I tested with another multimeter much cheaper and I have voltage.

DM805C AND TM801CS tested and I constantly have 180 V.

I tested the pins which go to backlight and there I have:
1 D+ 180V
2 S- 0.323 V
3 NC
4 S- 0.331
5 D+ 01.9 mV

When I touched pin 1 with 2 the tv works, I really haven't got what could be broken in that case.

[Relayer]

Re: Samsung UE32UH4003

Hello claudiuandrei2010,
Can you please check the voltages of the connector as shown in your modified picture below:



You need to check and record the voltages with the connector connected, and also with it disconnected.

EDIT:
Could you please also check the components marked in the two modified pictures below:





Check for shorts, as well as a punch-through test on the diode.
Please let us know your results.
Regards,
Relayer

[budm]

Re: Samsung UE32UH4003

I think my multimeter sucks, I changed from auto range to mV and I measured high voltage, now If I measured the voltage over 30V my Voltcraft 830 shows me "warning", in the manual of the multimer when that pops up there is a mistake with the lines. I suppose I blow up the fuse for low voltage.
I tested with another multimeter much cheaper and I have voltage.

DM805C AND TM801CS tested and I constantly have 180 V.

I tested the pins which go to backlight and there I have:
1 D+ 180V
2 S- 0.323 V
3 NC
4 S- 0.331
5 D+ 01.9 mV

When I touched pin 1 with 2 the tv works, I really haven't got what could be broken in that case.

You have open circuit in the LED string, that is why it went up to 180V! and S- (the Cathode of the first LED string) only shows 0.323V.
"When I touched pin 1 with 2 the tv works" do not do that again or you will damage the second LED string.