Samsung un40c6300 relay clicking

[rustover]

Hey guys, we had a bad storm here tonight and it messed up my Samsung 40 inch. The power relay cycles but the unit never powers up. No damage on the pwb or any component that I could find. All caps look good. I've work on tv's for years, but have been out of the game a long time. I'm trying to figure out if there are some test I can do to determine if its the psu or main board. Thanks in advance. Russ

[budm]

Re: Samsung un40c6300 relay clicking

https://www.badcaps.net/forum/showthread.php?t=39740

[rustover]

Re: Samsung un40c6300 relay clicking

Will get some pics tonight. Thanks.

[rustover]

Re: Samsung un40c6300 relay clicking

Got some pics. The psu is a PD46af1u_zd4, BN44-00356b, the motherboard is bn94-04492d.





Took some measurement on the psu to at cn802 that runs to the mb.



cn802

pin 1 D12V= 12.8
pin 3 D12V= 12.8
pin5 D12v = 12.8
pin7 gnd = 0
pin9 gnd = 0
pin 11 d5.3 = 5.3
pin13 d5.3 = 5.3
pin15 vamp = 17.1
pin 17 vamp = 17.1

Pin 2 det = 4.75
pin4 BL = .068
pin 6 pwm = 3.97
pin 8 h-sy = 5.0
pin 10 gnd = 0
pin 12 gnd = 0
pin 14 d5.3 = 5.3
pin 16 5.3 sb = 5.3
pin 18 ps = 3.2

All voltages cycle on and off with the relay with the exception of pin 16 SB which I'm guessing is stand by. I'm not sure what the abbreviations stand for except ground. I'm not sure what BL is but that measurement looks odd to me.

On the mb at cn401



I do have 3.3v at pins 3 and 10

Thanks for the help.

Russ

[budm]

Re: Samsung un40c6300 relay clicking

So the PS (PS-ON:Power supply ON) signal which is generated by the main board is cycling so the power supply will be turning on and off. The BL-ON (Backlights ON) which is also generated by the main board and it also is not present either (>2.5V = ON, <1V = OFF).
Try disconnecting the cable between the power supply and the main, plug the power cord back into the outlets then you should see the backlights come on right away without hitting the button, that will tell you if the power supply/LED backlights driver circuit are OK or not. I believe this power supply board has built-in pull-up resistors for doing the power supply self test. It looks to me at this point you have main board problem.

[rustover]

Re: Samsung un40c6300 relay clicking

I removed the cable and no back lights. The set is completely dead with the cable removed.

[budm]

Re: Samsung un40c6300 relay clicking

OK, I found the diagram, the board does not have pull-up resistor for doing the self test so for you to test the board you will need leave the cable between the power supply and the main board disconnected then use 500~1K resistor between the POWER ON/OFF pin 18 and the STBY pin 16 to force on the main power supply, and then another resistor of the same value between BLU ON/OFF pin 14 and and STBY pin 16 for forcing on the backlights.
But at this point I think you do have main board problem, you can put the cable between the power supply and the main board back in place but leave off the cable between the T-CON and the main to see if the TV will come on.

[rustover]

Re: Samsung un40c6300 relay clicking

Thanks Budm.

I did the test this evening and the TV did come on. I had the tcon cable removed and left the mb cable connected. The TV seemed to turn on. There was a single relay click but no back lights. I then unplugged the TV, removed the mb cable and plugged the TV in. I then heard the relay and had back lights.

I have started looking for the mb and they are not easy to find. Mine is a BN94-04492D. I did find a BN94-03366G which the site says is a substitute part # for 80 bucks shipped. I'm thinking about giving it a try.

I will let you know how it goes and I really appreciate the help. I haven't worked on TV's in years but have enjoyed troubleshooting this one.

Thanks again,

Russ

[tibimakai]

Re: Samsung un40c6300 relay clicking

I have the same TV with the same problem, but mainboards are always over $125, so for $80 jump on it.
Mine is clicking pretty fast, though.
Mine needs that 03366G.

[rustover]

Re: Samsung un40c6300 relay clicking

Purchased another board, I'm sure its used. Plugged everything in and doubled checked, I tried powering up the set and have the same problem, slow clicking relay on and off. I re-checked the measurements everything was the same as post# 4 except pin 2 Det, which instead of 4.75 volts was now 0. I know these are used parts and the set took a good surge. Its possible I got a defective board or possibly another problem. The power supply and LED's did power up when I did the other test. I may try to see if they will exchange the board. They show others in stock.

Thanks for the help. Russ

[tibimakai]

Re: Samsung un40c6300 relay clicking

From where do you buy these boards?

[rustover]

Re: Samsung un40c6300 relay clicking

http://populargadgetsale.com/index.p...roduct_id=1355

[tibimakai]

Re: Samsung un40c6300 relay clicking

Did you end up fixing this one?

[rustover]

Re: Samsung un40c6300 relay clicking

Did you end up fixing this one?

No, I sent the board back hoping to get a replacement, but instead got a refund which is good. I am still in need of a main board and looks as though they are a tough board to find.

Still keeping my eyes out for a used one.

[tibimakai]

Re: Samsung un40c6300 relay clicking

I have just picked up a UN55B8000, with the same clicking sound.

[sangdy]

Re: Samsung un40c6300 relay clicking

Did you end up fixing this one? Mine have the exact the same problem, replaced the MB but no luck.

BTW, for the PSB, I noticed a small area looks like burned, not sure if it's where the problem is, seethe attached pics.

[tibimakai]

Re: Samsung un40c6300 relay clicking

I haven't, but I still have it.
Did you force yours to turn on, without the mb?
Mine turns on and the LEDs turn on as well.

[rustover]

Re: Samsung un40c6300 relay clicking

I did get my unit fixed. I got to thinking about it, I knew I could force it on without the mb, so I took a chance on another mb and it fixed the problem. My daughter has been using the tv now for about a year now.

[tibimakai]

Re: Samsung un40c6300 relay clicking

You should have not ordered that mb. First, you have to be sure, that you ps and led backlight works.
Now you will have to do some measurements and post it here. What you are getting, at that connector?

[mmartell]

Re: Samsung un40c6300 relay clicking

Lol tibi, he said the new main board fixed it.