Samsung UN39FH5000FXZA - No Picture, Has Sound

[ECU_Techie]

Hi guys,

Ok, so I just picked up this TV which, at first glance looks like it has no picture, but upon unconnecting one of the two cables providing display to the screen, you can tell the back-light for one side of the screen lights up.

I checked all the voltages on connector CNM803 on the PS board and they all checked out good for what they should read according to the board. They are listed below:

1. PWM_DIM - 13V
2. B13V - 13V
3. BLU_ON/OFF - 13V
4. GND
5. GND
6. A5V - 5.2V
7. POWER ON/OFF - 5.2V

I then checked the surface mounted fuse on the T-Conn board which I believe is FP1 and it has 12.9V running through it.

Possible main board issue? Any ideas on what I should check? Thanks!

[budm]

Re: Samsung UN39FH5000FXZA - No Picture, Has Sound

'pwm_dim - 13v
b13v - 13v
blu_on/off - 13v
gnd
gnd
a5v - 5.2v
power on/off - 5.2v'

Those cannot be right, you must have measured the wrong pins or count them wrong.
But since the backlights are working then the power supply/LED driver board is OK.
It sounds like yo u have panel problem if you can can normal image on half of the screen if one of the two ribbon cables from the T-CON to the LCD panel is connected one at a time but not both.

[ECU_Techie]

Re: Samsung UN39FH5000FXZA - No Picture, Has Sound

My DMM is set to 20V DC and that is what the pins all read from the top down.

**EDIT**

Ah, my bad. How blind of me. It didn't dawn on me that it is two rows of pins. I was thinking the first column was the name of the pin out and the second was the value for some odd reason... I really need to sleep more!! Haha!

[budm]

Re: Samsung UN39FH5000FXZA - No Picture, Has Sound

The connector has to rows of pins, those you can see from the top side of the board are the ODD number pins, the EVEN number pins cannot be seen from the top side, you have to use skinny probe to get to the pins on the back side of the female connector or from the bottom side of the board.
B5V, B13V, Vamp are switched power supplies which will be present when PS-ON signal from the main board is present.

[ECU_Techie]

Re: Samsung UN39FH5000FXZA - No Picture, Has Sound

Ok, now armed with this new found outlook on the issue, this is the voltages for the pin outs starting in the left top column going down:

*Note: These readings were taken with the TV turned on and out of standby.*

• PWM_DIM - 1.03V
• B13V - 13V
• BLU_On/Off - 4.8V
• GND
• GND
• A5V - 5.28V
• Power On/Off - 3.36V
• B13V - 13V
• B13V - 13V
• Vamp - 13V
• Vamp - 13V
• GND
• B5V - 5.26V
• B5V - 5.26V

[budm]

Re: Samsung UN39FH5000FXZA - No Picture, Has Sound

The Voltages are fine, you do have backlights.
As you have indicated that you do get the image on the screen if only one of the ribbon cable to the LCD panel is connected but not both.

[ECU_Techie]

Re: Samsung UN39FH5000FXZA - No Picture, Has Sound

Yes, I do get an extremely faint image on one side of the screen and in that image there can be some parts that has horizontal lines/sections of it missing.

[ECU_Techie]

Re: Samsung UN39FH5000FXZA - No Picture, Has Sound

For the voltages on the connector (CNL802), going to LED strip I only get a reading of 212V on the two D+ pin outs. The rest read 0V.

On the PS board though, it says CNL802 should read 135V. Is it saying it should read 135V on each D+ pin out instead of the 212V on each I am getting?

[budm]

Re: Samsung UN39FH5000FXZA - No Picture, Has Sound

Post 1: 'you can tell the back-light for one side of the screen lights up'
So are you getting backlights or not?
If you disconnect the cable between the main board and the power supply board then the backlighst should come on and stay on as soon as you plug the TV into the AC outlets.

[ECU_Techie]

Re: Samsung UN39FH5000FXZA - No Picture, Has Sound

Ok, well this TV is done for. Two things I believe are going on with it. I took off the panel to check the LEDs and see if they came on at all and while I had the panel off I decided to check from the backside to see if everything was good. No such luck...

I discovered the panel is cracked in two corners. I can assure you it wasn't from me taking it apart either. Apparently I was failed to be told the screen got cracked. At least it was a free TV!

I checked the LEDs anyways though since I got that far. There are three rows of LED strips in this TV. Upon turning it on, the very bottom row would light up slightly for a millisecond and that was all the activity i'd get. Maybe an LED some where shorting itself out thus causing none of them to come on/stay on?

[jeffer76]

Re: Samsung UN39FH5000FXZA - No Picture, Has Sound

Do you still have the LED strips? I could use them.
Let me know.