Samsung / Hansol BN44-00428b

[budm]

Re: Samsung / Hansol BN44-00428b

The power supply/LED driver board has built-in pull-up resistors that allow you to do the self test of the board.
When the cable between the power supply board and the main board is disconnected and then you plug the TV into the outlet, if the power supply and the backlights circuit are OK, the backlights should come on and stay on as long as the TV is plugged into the outlet.

[Louis82]

Re: Samsung / Hansol BN44-00428b

UPDATE: My tv is fixed. Problem was the main board which means that the readings I posted earlier were the right values of a working power supply. This power supply or at least the one I was working on, doesn't turn on or activate the backlights by simply disconnecting it from the main board. I found somewhere the steps or procedure of how to test the backlight. I have attached the pdf file. My power supply board was BN44-00428B ad tv model number UN55D6450.

Thank you all for the help. I hope this info can help.

[budm]

Re: Samsung / Hansol BN44-00428b

Ah, it needs high ON PWM DIM lines due to no pull up on the LED driver IC.

[Curt1915]

Re: Samsung / Hansol BN44-00428b

The cold soldering joints were the problem! I opened up the TV added more solder to the joints specified and boom.....no more clicking off and on problem! Thanks everyone for the help.

[snb1990]

Re: Samsung / Hansol BN44-00428b

Louis82, What did you do to fix the problem with the main board? I am having the same issue and when the power is disconnected, the backlights work fine and the TV doesn't cycle.

[albaben]

Re: Samsung / Hansol BN44-00428b

please i need BN4400427A scheme, 46 '', PSLF151B03A. mainly I have in this area that I put in the picture. can anyone help me?

[budm]

Re: Samsung / Hansol BN44-00428b

What is your board not doing?

[albaben]

Re: Samsung / Hansol BN44-00428b

What is your board not doing?

ICS801 is damaged (D3011K) PC802S, 801S (NEC2561) ZDS802 (zener). I put these friends. But some elemnte I do not know what they are.
- DQ854 ??
- QQ852 ??
- ICS851 ??
and RS857 (471) and RC856 (302)

Once I replaced the elements which I have written above, now turns on stand-by, but the pas few flashes of red light stand-by.
I believe the problem lies in SMD elements that I can not specify what they are to replace.
so I ask a scheme for this power-supply

[raxen]

Re: Samsung / Hansol BN44-00428b

*****Fixed******

I had the same exact problem as the OP and this is what fixed my problem.

I found that the main transformer TM801S had a cold solder if you look at the 3 pictures I posted. The first shows the front of the board with a yellow arrow pointing at the joint that was bad. The 2nd and 3rd show the back of the board with a yellow arrow pointing at the bad joint. I hit it with my soldering iron and problem fixed.

BTW I found this problem because I just happened to see that joint arcing every time the power relay would click.

Problem started with clicking relais. No samsung logo.
With cable 28p (the cable from psu to mainboard) disconnected. The backlight turned on and starts flickering with buzzing sound from psu.
Solder points resoldered of transformer.

Problem solved.

Thanx for the info!

[aa6910069]

Cycling of Samsung Power Supply/Inverter for Model#: UN55D6900WF LED TV



I had a similar problem of the Power Supply on this Samsung LED TV recycling on and off where you can hear the main relay clicking on and off

After extensive tracing and diagnosing (and lots of luck----I did not have a schematic to work with) I found that if you ground the collector tab of D9052 to COLD Ground, the cycling will cease and a normal operation is restored.

Apparently, on this Model TV set, if the Light Inverter circuit senses an anomaly to the current and voltage fed to the LED light banks, it will throw off and error signal to the input pins of D9052 which will turn the collector of D9052 (tab---the center outward pin) to 3v instead of virtual zero volts. This 3 volts will trigger the cycling of the power supply.

I've ground d9052 and the power supply now is working normally. It was hard to find d9052. Many thanks for your help.

[triplefour]

Re: Samsung / Hansol BN44-00428b

i have UN55D6400UF

AND well i done goofed. i followed this thread (very helpful and confusing at the same time) and i was able to use the trick in post 62 to see that i probably had some bad LED's
the psu kept resetting and relay clicking, and backlight flash for half a second, when i tried with DIM4, DIM3, DIM2 jumpered to the A5V. but when i tried with DIM1 jumped to A5V i was able to see the backlight stay on, and the relay stop clicking. psu not resetting. so... a little different than what was said in that tip, but close enough. i noticed in this mode, there was a missing band of light near the top of the screen.
aha! so i disassembled the panel (quite difficult, as the tiny screws love to strip if u dont apply enough pressure, i ended up having to drill some of them out)
sure enough when i got in there and started testing with my LED tester, i found 8 bad LED's in a row at the top of the left strip.

i lucked out and had a set of strips for the UN46D6400UF lying around so i went ahead and removed 8 LEDs from one, and removed the 8 bad LEDS, prepped the pads, and was soldering each LED in place with hot air at around 350c... i was on the LAST one, which was the first one, closest to the plastic connector which i noticed was getting a little melted from the hot air.
i swear i barely touched it to check, and it completely tore off!

my question is: have i totally screwed myself? or can i use the 8 solder points next to the connector, solder a bunch of tiny wires to each one, and solder each to its respective pin on the connector... and kinda rig it up? (of course i have a hard time seeing which pin each solder pad was supposed to go to, even when the connector was fine, if that even is what is going on)

or... could i possibly use the strip from the smaller tv? ...and add in some LEDS?
fishing in the dark here.... so disappointed in myself. i was SO CLOSE... shoulda went slower and gave more time between LEDS to let that connector rest....
maybe i should have only gone from underneath no matter how long it took...

the second picture is of the strip for the 46" its identical except shorter (LESS LEDS)

[sam_sam_sam]

Re: Samsung / Hansol BN44-00428b

Is there any of pads on the board left at all

[triplefour]

Re: Samsung / Hansol BN44-00428b

yea after investigating it, i know i can do it, i just gonna have to run some thin wire for a couple spots...one wire will have to go all the way to the end of the strip

[triplefour]

Re: Samsung / Hansol BN44-00428b

well, if only to prove it to myself, i went ahead and fixed the wiring on the strip (not pretty, trust me) and put the tv back together. everything works great except one half of the panel appears to be damaged. the other side is fine. this panel has those dangling "edge tabs" on the sides. am i crazy or did someone suggest ripping these off to fix a panel?


...if not at least i know i have a good MB PSU and TCON

[naldymap]

Re: Samsung / Hansol BN44-00428b

i am looking for a BN44-00428REVA PS schematic for UDF55D8000YJ. I have an open RS805 (0.51ohm/2w) and no traces of busted DS3011K ic. The wiring is different from the REVB that i got from this tread. Thanks in advance..

[budm]

Re: Samsung / Hansol BN44-00428b

Can we see the pictures of the whole board?
What is the designator of that DS3011K?

[naldymap]

Re: Samsung / Hansol BN44-00428b

Uploaded the whole board. Was able to check the D3011K and is for the standby voltage. I am tracing why the 2W resistor got burnt from the pin 4 (FB) of the IC. I will trace the pcb layout later and update.

[budm]

Re: Samsung / Hansol BN44-00428b

What is the designator for the D3011K?
Never mind, it is the SMPS IC.

[naldymap]

Re: Samsung / Hansol BN44-00428b

Budm, yes it is SMPS IC. I traced and the busted 0.51 ohm is connnected to pin 1-S/OCP. The rev B diagram has the same resistor value (only 1W) but with parallel Schottky diode. My board doesn't have the diode nor pcb trace so it must be the rev issue. I will go ahead and replace the busted resistor and plug the unit. I hope my SMPS IC is still working since replacement IC here in HK is hard to find.

[budm]

Re: Samsung / Hansol BN44-00428b

That resistor is connected between Source pin of the internal power MOSFET, the other end of the resistor is connected to the hot side circuit GND, that resistor is blown open due to shorted out MOSFET inside that SMPS IC, you better replace the IC instead of taking an chance of causing more damage to the circuit.