Samsung 50 inch LED no picture model UN50EH5000

[JohnO FL]

I have done a little bit of trouble shooting and am hoping someone here can maybe give a diagnosis. I have sound but no picture. In a dark room with a flash light i can faintly see the picture. i have no back lights. The TV has had problems with randomly shutting off. Sometimes it comes right back on, Sometimes it does a few power cycles. Sometimes i can't get it to come back at all and just have to walk away. I don't see any bad caps on any of the boards and no obvious damage to them. Below are the Power board and T Con. Any suggestions are welcome. I'd rather not buy a new TV if i can fix it.

[dskall]

Re: Samsung 50 inch LED no picture model UN50EH5000

Can we get a picture of mainboard and whole back of tv

[JohnO FL]

Re: Samsung 50 inch LED no picture model UN50EH5000

absolutely!

[art_dodger]

Re: Samsung 50 inch LED no picture model UN50EH5000

If you disconnect the main board connector labelled "14" (the cable running between the main board & power board) & apply power, do the backlights come on?

[Andrew F. Ali]

Re: Samsung 50 inch LED no picture model UN50EH5000

This a failed LEDs backlight problem....however the LED Driver could cause this problem too......Let's wait and see what happens when he disconnects the main board connector labelled "14" (the cable running between the main board & power board) & apply power.

[JohnO FL]

Re: Samsung 50 inch LED no picture model UN50EH5000

nothing happens it's black no back lights and looks pretty much dead when i disconnect 14.

the power button is on the side connected to the main board so by applying power you mean just plugging in?

[dskall]

Re: Samsung 50 inch LED no picture model UN50EH5000

Need to post some voltages from your connector from power board to main. With the pin id and voltage. Looks like there is a bl-on can't quite read. If so that is your signal for your backlights

[JohnO FL]

Re: Samsung 50 inch LED no picture model UN50EH5000

is this the part you are talking about? i dont see a bl -on

[budm]

Re: Samsung 50 inch LED no picture model UN50EH5000

BLU-ON = BL-ON
That power supply board may have the pull-up resistor for for the PS-ON , BLU-ON already so check the DCV too on those pins when that connector is not in place.
We also need the DCV on the LED connector pins with ref to the chassis GND when TV is off and when TV power switch is activated.

[JohnO FL]

Re: Samsung 50 inch LED no picture model UN50EH5000

uuuuuuuummmm? ok i'm going to get a voltmeter thingy from my dad tomorrow. i'll post a pic and can you tell me where to put the probes and what setting to be on?

Sorry i am a total noob to this. Starting to seem like i'm in over my head and just need to pay for a new tv.

[heavymachines]

Re: Samsung 50 inch LED no picture model UN50EH5000

You're in good hands with budm and others, just pay attention to what is being said and common sense most of your measurements will be done with black probe on chassis ground and red probe where you are told to get readings from labeled pins. budm does ask regularly for measurements across the primary big caps on power board (usually the biggest capacitors on power board) in this case red probe on positive leg and negative probe on negative leg with power switched on and make sure you're not touching anything. All capacitors are labeled with negative unless it is non polarized. Also will tell you what setting your meter should be on. No need to be overwhelmed.




EDIT: Safety details added.

[dskall]

Re: Samsung 50 inch LED no picture model UN50EH5000

The voltmeter thingy is easy to use. I'm able to use it so you should have no problem

[JohnO FL]

Re: Samsung 50 inch LED no picture model UN50EH5000

below is the voltmeter i have. what setting do i put the dial on?

and when you say on the pin, do you mean the metal pieces that come out the back of the connector and goes down do the board? and i assume the diagram next to it with the 7 boxes shows me which is which right?

Please be specific as to when i should have it plugged in and or turned on/off while doing this. i am a little nervous of sticking metal probes in something that is live with electricity.

[dskall]

Re: Samsung 50 inch LED no picture model UN50EH5000

Setting in the picture should be fine. The brown power board is marked hot and cold. There is a line dividing them. The hot side has dangerous voltages. You will be measuring on cold side so little danger. On cold side you will put black probe on metal back. Red probe will go on each terminal of connector that goes from power board to main board. Record each reading. The tv will be plugged in but not on. The probe will go down alongside the wire on the connector till it makes contact.

[Andrew F. Ali]

Re: Samsung 50 inch LED no picture model UN50EH5000

If you disconnect the main board connector labelled "14" (the cable running between the main board & power board) & apply power, do the backlights come on?

'apply power' means to just plug in the 120Vac or wall outlet receptacle.

[JohnO FL]

Re: Samsung 50 inch LED no picture model UN50EH5000

So i got some measurements then reconnected plugged in and get no red light indicator and no response when trying to turn on. see pic it's all connected back the way it was and seems dead. Does this indicate anything? i dont think i broke any parts either. It's almost like i mentioned in my original post. Sometimes it would shut off maybe it comes back on in a second maybe it takes a minute maybe it takes hours. then it will go months without it happening. now it's dead.

[dskall]

Re: Samsung 50 inch LED no picture model UN50EH5000

Setting in the picture should be fine. The brown power board is marked hot and cold. There is a line dividing them. The hot side has dangerous voltages. You will be measuring on cold side so little danger. On cold side you will put black probe on metal back. Red probe will go on each terminal of connector that goes from power board to main board. Record each reading. The tv will be plugged in but not on. The probe will go down alongside the wire on the connector till it makes contact.

Need to do this

[JohnO FL]

Re: Samsung 50 inch LED no picture model UN50EH5000

sorry i did that earlier should have posted the numbers.

P_DIM - 12.4
B13V - 12.4
BLU_ON - 12.4
GND - 12.4
GND - 0
A5V - 5.2
PS_ON - 5.2

[dick_barton]

Re: Samsung 50 inch LED no picture model UN50EH5000

There are 14 pins as shown on the legend alongside.
7 top row and 7 lower row
The top row you can see as in post#8 left -> right are
Pins 1,3,5,7,9,11,13
and the lower row left -> right
Pins 2,4,6,8,10,12,14

The readings you have given are not correct.

[JohnO FL]

Re: Samsung 50 inch LED no picture model UN50EH5000

i removed the connector and put the red probe on each of the 14 pins in there for a reading and using the numbers you mentioned above as the layout.

1 - 12.4
2 - 3.3
4 - 12.4
5 - 12.4
6 - 2.9

Then when i touched 7 there were some very small sparks and now got no reading and when i go back to 1 through 6 they all read zero.