Samsung UN32F6300AFXZA black screen red flashing lights

[Davegerg]

I picked this 32" LCD up and all it will do is flash the red light 5 times and nothing else. Occasionally, I will hear a chirp or click through the speaker - but that's only happened a few times. The caps look good and I've tested most (but only on the board). I've measured the voltages. Note pin #4 starts at about 2.5 but very slowly starts sinking.
pin - label - reading
1 B13V 12.86
2 DIM 4.71
3 B13v 12.86
4 ECO 2.5
5 Vamp 12.86
6 BLU 4.71
7 Vamp 12.86
8 GND -.3
9 GND -.3
10 GND -.4
11 B5V 5.25
12 A5V 5.25
13 B5V 5.24
14 PS 3.28

Any help would be appreciated!

[Andrew F. Ali]

Re: Samsung UN32F6300AFXZA black screen red flashing lights

PSU Bd is good. I believe you do have a Main Bd problem. Although I'm a bit unsure of that Pin 6-BLU voltage.
Performed POWER BD 'self test' as follows:
1. Disconnect CNL802-jack to Back Light Unit.
2. Disconnect CNM803-jack to Main BD.
2. Connect a 1kOhm resistor across Pin 12-A5Vdc and Pin 14-PS
3. Connect another 1kOhm resistor across Pin 12-A5Vdc and Pin 6-BLU.
4. Re-install PSU BD with ALL screws in place
(Be careful not to short circuit any connections to each other and to chassis GND).
5. Re-connect CNL802-jack to Back Light Unit.
6. Apply 120Vac.
If PSU is working Back Lights will come ON and remain ON.

Actually I am looking for a Main bd No. BN94-06779U for a UN32F4300AFXZP.....Looking at your board it looks very similar to what I need. The difference is my board has two (2) HDMI and USB Inputs and yours have three (3). This gives me an idea....thanks

[Davegerg]

Re: Samsung UN32F6300AFXZA black screen red flashing lights

Thanks! Will try that later today - headed outside for a few hours.

[budm]

Re: Samsung UN32F6300AFXZA black screen red flashing lights

BLU = BL-ON, you should have Backlights right now, the main board is sending all the correct signals.
The LED strings are connected in series.

[CapLeaker]

Re: Samsung UN32F6300AFXZA black screen red flashing lights

Since you said: "it flashes a few times and nothing else"
Does that mean your backlight isn't on either? Because if it isn't on in your case you have bad LED's.

[Davegerg]

Re: Samsung UN32F6300AFXZA black screen red flashing lights

Andrew - I added the resistors and just reattached CNL802 like you said - no back-light.
Budm - no back-light before or after adding the resistors.
Capleaker - I said the red light flashes (bottom right corner). Actually, this indicator light comes on, flashes on/off 5 times and goes out.
Also - after the red light flashes and goes out, I hit the power button and one time heard the chirp or click noise. When that happened, a red LED on the mb lit up. it's in a square box marked OL301 (next to the blue component video connector).

[budm]

Re: Samsung UN32F6300AFXZA black screen red flashing lights

You already have the correct signals and Voltages, so forcing on with resistors is not going to make any difference.
You need to start checking Voltages in the LED driver circuit.
What is the P/N of this power supply/LED driver board?
BNXX-XXXXXX?

[CapLeaker]

Re: Samsung UN32F6300AFXZA black screen red flashing lights

Andrew - I added the resistors and just reattached CNL802 like you said - no back-light.
Budm - no back-light before or after adding the resistors.
Capleaker - I said the red light flashes (bottom right corner). Actually, this indicator light comes on, flashes on/off 5 times and goes out.
Also - after the red light flashes and goes out, I hit the power button and one time heard the chirp or click noise. When that happened, a red LED on the mb lit up. it's in a square box marked OL301 (next to the blue component video connector).

I was asking if the backlight was coming on... I didn't mean the little LED up front blinking 5 times, I meant a the little LED's string behind the screen!

[Davegerg]

Re: Samsung UN32F6300AFXZA black screen red flashing lights

The board is BN44-00606A. I will start checking the voltages. Capleaker - sorry, I should have stated what the back-light was doing.

[Davegerg]

Re: Samsung UN32F6300AFXZA black screen red flashing lights

Hi, I just checked all the pins on CNL802 and they all read around 2v (from 1.9 to 2.1) except pin 12 - it varies from 190 to 220. That's what my meter says - could this be right?

[budm]

Re: Samsung UN32F6300AFXZA black screen red flashing lights

Hi, I just checked all the pins on CNL802 and they all read around 2v (from 1.9 to 2.1) except pin 12 - it varies from 190 to 220. That's what my meter says - could this be right?

You have open circuit in the LED strings, I am not surprised.

[Davegerg]

Re: Samsung UN32F6300AFXZA black screen red flashing lights

Bingo! I took the LCD off to expose the LED strips (fairly easy to do). Tested each LED individually and they all worked. I noticed one of the smd components looked a little strange and with a big magnifying glass, realized one was burnt nearly in two. A few of the others looked a little toasted. Can you tell me what these are? The left one is marked "4E BJ" and the right, "2 AI". Photo attached.

[budm]

Re: Samsung UN32F6300AFXZA black screen red flashing lights

Does each LED strip have those two components? Are they connected in series with the LED, if they are, then they may be Diode or resistor.

[Davegerg]

Re: Samsung UN32F6300AFXZA black screen red flashing lights

Yes, each of the five strips look identical. These components do appear in series. I reoriented the diagram so this is the way they appear on the strip. Note the bars on the right one - like the bar on a diode, maybe? Thanks.

[Davegerg]

Re: Samsung UN32F6300AFXZA black screen red flashing lights

My updated diagram didn't get loaded. Here it is.

[Andrew F. Ali]

Re: Samsung UN32F6300AFXZA black screen red flashing lights

Try a resistance check across the good one and then try a diode check

[Davegerg]

Re: Samsung UN32F6300AFXZA black screen red flashing lights

I've been doing some testing and gotten some odd results. Also got a 24v power supply and tested all five strips - four work and the one pictured does not. The SMDs on the four good strips test as caps in the 40-70pf range. On the bad strip, the "2 AI" chip tests as a diode! I'm going to dig up two caps and put them on the bad strip - later tonight.

[budm]

Re: Samsung UN32F6300AFXZA black screen red flashing lights

You need to find out how the two legs of those two devices are connected in relationship to the LEDs. The LEDs on each strip are connected in series. Then you have two contact points on each strip, one will be positive. one will be negative, so I would trace out the connection from the positive terminal to see if it is connected to the ANODE of that unknown Diode or not or if it is connected the the ANODE of the first LED.
Open capacitor will not cause the LED strip not to light up, open Diode (if it is connected the LEDs in the string) can cause the LED strip not to light up.
BTW, it is not a good idea to connect the power source directly to the LEDS without having current limiter.

[Davegerg]

Re: Samsung UN32F6300AFXZA black screen red flashing lights

Budm, I think I read your last post way too late!
Those two devices are connected just like that diagram in my photo. The neg contact point goes to "4E BJ", which is connected to "2 AI", which goes to the pos contact. So, they're not in series with the LEDs. I replaced both of those devices with caps (the smd's on the other four strips all read as caps - the fifth strip had one burned smd and the other read as a diode). Anyway, I hooked up my 24v PS and it worked. THEN, things started going south. I left the power on for about 6-8 seconds and the LEDs started flashing. I turned it off real quick and now one LED is dead. The PS I used is 24VDC and 5A. I always thought a device would just use as much amperage as it needed. I'm wrong, aren't I?

[budm]

Re: Samsung UN32F6300AFXZA black screen red flashing lights

"The PS I used is 24VDC and 5A. I always thought a device would just use as much amperage as it needed. I'm wrong, aren't I? " Yes.