Samsung UE40C6000RWXXH - clicking, won't turn on

[icefire]

So there is one more Samsung TV which clicks and refuses to power up. When connected to mains, the red Standby LED lights up. When trying to turn the TV on, it clicks and doesn't fire up. The standby LED goes on and off in turn with the clicking.

TV Model: UE40C6000RWXXH
Power Supply: BN44-00357A, Schematic here.
Mainboard: BN41-01444B

What I have done so far:
- I have confirmed that there is standby voltage (the red LED goes on, duh )
- A visual inspection of the power supply PCB shows no bulged capacitors and (on the back side) no bad solder joints
- All fuses are ok
- If I unplug the mainboard from the power supply and connect pins 16 and 18 together (PS_ON and STDBY on the CNM801 connector - to simulate the turn on signal) the LED backlight fires up immediately - so this indicates that the power supply should be ok...

So it looks like it's the mainboard, however I must confess that I have no experience repairing mainboards... I am no electronics expert but I have managed to cope with a lot of repairs of household appliances ... up to now Maybe you could guide me what to check on the mainboard... and if a mainboard repair is at all possible... Any help will be highly appreciated Thank you

[nomoresonys]

Re: Samsung UE40C6000RWXXH - clicking, won't turn on

First things first: Test connector from mainboard to powerboard on powerboard side, sholud be a little legend/map of expected voltages, test with tv plugged in but off then hit power, report both conditions here, give pin number, pin description and condition on and off, demonstration in signature below.

[R_J]

Re: Samsung UE40C6000RWXXH - clicking, won't turn on

Check this thread https://www.badcaps.net/forum/showth...ht=BN41-01444B This might be your problem
You can also use Search and enter your main board number BN41-01444B

[icefire]

Re: Samsung UE40C6000RWXXH - clicking, won't turn on

Thank you both for your help so far.

Check this thread https://www.badcaps.net/forum/showth...ht=BN41-01444B This might be your problem
You can also use Search and enter your main board number BN41-01444B

I checked it out but I couldn't figure out which caps these are... I practically have only SMD components on my mainboard (see the first post for a picture). There are also no shields like on the one mentioned in that thread so I can't figure out which caps I should test...

First things first: Test connector from mainboard to powerboard on powerboard side, sholud be a little legend/map of expected voltages, test with tv plugged in but off then hit power, report both conditions here, give pin number, pin description and condition on and off, demonstration in signature below.

Here is the chart. Condition OFF means TV plugged in but off and Condition ON means with PS_ON active (i.e. when the mainboard tells the powerboard to fire up)

[nomoresonys]

Re: Samsung UE40C6000RWXXH - clicking, won't turn on

Maybe try heating with a hairdryer small sections at a time on mainboard, see if tv starts working or anything changes.

[R_J]

Re: Samsung UE40C6000RWXXH - clicking, won't turn on

That thread I refered must be for a different board, Is your PS_ON voltage changing as the power supply is clicking on and off?

[icefire]

Re: Samsung UE40C6000RWXXH - clicking, won't turn on

Maybe try heating with a hairdryer small sections at a time on mainboard, see if tv starts working or anything changes.

I just tried. Nothing changes. However, while the clicking goes on and on, I noticed that the red chips get warm and the green one stays cool:


So there is definately something going on there. Once I warmed everything up with the hair dryer, the red chips remained warm while the green one cooled down after some time.

That thread I referred must be for a different board, Is your PS_ON voltage changing as the power supply is clicking on and off?

The sequence is like this:

1. PS_ON becomes active and one click follows. The red LED starts blinking. This goes on for a few seconds
2. The TV shuts off, the relay clicks again, PS_ON becomes inactive, the red LED stops blinking
3. One second later, the TV starts again, the relay clicks again, the red LED starts blinking - this loop goes on forever.
___________________

I have another question. Could it have to do anything with the EEPROM chip?
As far as I could find out this is the EEPROM chip:


When the TV is on, I get 3.18V on all pins on the left side and 0V on all pins on the right side:



The chip specification is: S24CS0 / 2AVK4 / K670
Here is the datasheet (I hope this is the correct one): https://cdn.badcaps-static.com/pdfs/...896d3864d3.pdf

According to the pinout diagram I should have VCC just on pin 8. However, I get 3,23V on all pins on the left side. Is this normal? Even though I get the same voltage on all four pins, there is no continuity between them, i.e. they are not shorted.

Could this give us some hint where to go from here?

[icefire]

Re: Samsung UE40C6000RWXXH - clicking, won't turn on

ok, after a lot of reading and thinking I think it is either the eeprom chip or the IC8001 - SDP 91 BGA chip (the one with the green circle that remains cold). There is no input voltage on the T-Con and as far as I understand the IC8001 could be responsible for that. Does anyone have any thoughts on this or should I try and solder in a new SDP91 chip?

[William1967]

Re: Samsung UE40C6000RWXXH - clicking, won't turn on

The chip in the green circle is in most cases the culprit and must be reballed , I've seen a lot of these mainboards and almost always that chip is the problem. If you search for a mainboard for a Samsung don't search with the BN41-xxxxX number but use the BN94-xxxxX number on the label. Beware, a lot of them have problems.

[nomoresonys]

Re: Samsung UE40C6000RWXXH - clicking, won't turn on

Could try a heatgun reflow of the chip, can check some youtube videos or type it in the searchbox here.

[icefire]

Re: Samsung UE40C6000RWXXH - clicking, won't turn on

I did a heatgun reflow, first on the top side and since it didn't work I tried it once more from the underside. Still no joy.

I used aluminum foil to cover everything else and a laser thermometer to make sure I don't burn the chip with the heatgun. I kept the chip temp. 250 deg. C (480 deg. F) for about 30 seconds.

Maybe buy a replacement chip and resolder it? They are like 7$ on aliexpress...

[icefire]

Re: Samsung UE40C6000RWXXH - clicking, won't turn on

Update:
I baked the mainboard in the oven for 10 min at 200 deg. C (400 deg. F) and now it turns on and looks like this:



If turn it off via remote control and then turn it on again it starts restarting itself again but this time with the above picture. If I unplug the TV and then plug it in again, the picture comes on without restarting... until I turn it off.

Could it be that the T-CON Board is defective as well?

Thank you!