Samsung UN55C6300SFXZA won,t power up

[dfergy54]

Hello all, I got this set the other day and began checking it out.
The guy I bought it from said he had the power supply replaced and then a month later it quit again , the repair center then said it was the main board.

I found Toms schematic on the PSU and so far cannot isolate a fault condition. Tried disconnecting the Logic but it won,t click the relay.


It continuosly cycles the relay on the PSU about once every 6 seconds Approx.
The only full voltages are the 5.3 standby, 5 volt CS803 supply and the 385 volt CP801-804 CS802 complex DC at the top of the board. My best guess is this is used for the LED backlight arrays?
The other voltages try to come up with a 3 pulse output but get shut off when the relay clicks in.
All the fuses are good, can,t detect anything getting hot anywhere.
Red power light on the front stays on all the time, No screen activity, and does nothing with remote.
Anybody got any stick time on this set or similar?

[tom66]

Re: Samsung UN55C6300SFXZA won,t power up

Part # of PSU? BN44-xxxxxxx

[dfergy54]

Re: Samsung UN55C6300SFXZA won,t power up

Bn44-00358b

[tom66]

Re: Samsung UN55C6300SFXZA won,t power up

OK pin 18 of CNM801 as power is cycling what do you measure?

[tom66]

Re: Samsung UN55C6300SFXZA won,t power up

Schematic for others:-

[dfergy54]

Re: Samsung UN55C6300SFXZA won,t power up

I,m not at the TV now but will check when I get home. Part of the problem checking this set is the pin descriptions on the logic versus the PSU don,t match , and pin 18 goes through to the bottom of the psu and the triggers QS803 etc are surface mounted on the bottom. Traced it through 3 devices to a jumper on the top and it showed 2.25 volts toggeling to zero.

[dfergy54]

Re: Samsung UN55C6300SFXZA won,t power up

Pin 18 at psu board, pulses 3 times 25 MS ea at plus 3 volts, causing the relay to re energize and supply 120 volts to the primarys of the power supply for about 4 seconds.
Then stays at gnd untill the next set of pulses to start the sequence again.

[dfergy54]

Re: Samsung UN55C6300SFXZA won,t power up

Does anyone know what the reference to P Gnd means?
Power ground ?

I find it in all the control IC circuits on this schematic.

[dfergy54]

Re: Samsung UN55C6300SFXZA won,t power up

used a 1k resistor and forced "power on" high, still would not keep the relay closed.

[dfergy54]

Re: Samsung UN55C6300SFXZA won,t power up

Don,t know , but maybe the power on signal is supposed to be pulsed continously to finish power on sequence. Most sets seem to come on partially like a computer posts when you plug them in and then go to stby.

Apparently with the samsungs the red light on the front stays on in standby and only goes off on power up.

So i guess it fails post and starts re booting trying to finish post?

I read that the newer circuitry checks for over and under current and maybe under and over voltage as well,
The FB signal which is ??? seems to be a consistent input to all the safety chips.

[dfergy54]

Re: Samsung UN55C6300SFXZA won,t power up

Found good info on one of the IC,s that regulate current and voltage for the backlights/LED,s

[tom66]

Re: Samsung UN55C6300SFXZA won,t power up

PSON should be pulled high to turn the set on, use a small resistor connected to the 5.2V standby.

You should get +18V, +12V and +5.3V coming up.

Then connect BLU ON/OFF and the backlight should turn on too.

[dfergy54]

Re: Samsung UN55C6300SFXZA won,t power up

PSON should be pulled high to turn the set on, use a small resistor connected to the 5.2V standby.

You should get +18V, +12V and +5.3V coming up.

Then connect BLU ON/OFF and the backlight should turn on too.

Did you mean Pwr_on/off Pin 18 on CNM801 from Main logic?

[tibimakai]

Re: Samsung UN55C6300SFXZA won,t power up

My 46C6300 was clicking too, PS_ON was changing states constantly.
I have removed the PS_ON wire from it's connector and I have measured it that way.
I have replaced the board with one of those semi empty boards from Ebay(3066R) and it's working fine. It's in my living room.

[dfergy54]

Re: Samsung UN55C6300SFXZA won,t power up

My 46C6300 was clicking too, PS_ON was changing states constantly.
I have removed the PS_ON wire from it's connector and I have measured it that way.
I have replaced the board with one of those semi empty boards from Ebay(3066R) and it's working fine. It's in my living room.

I searched Ebay for Samsung main board nothing with (3066R) in it?
Is it a BNxx-XXXXX part number?

Clarification Please.

[attainteddragon]

Re: Samsung UN55C6300SFXZA won,t power up

you will be looking for the bn number.

[tibimakai]

Re: Samsung UN55C6300SFXZA won,t power up

You have to do your own research. You have to check which panel do you have and go from there.
http://www.shopjimmy.com/catalogsear...pe]=Main+Board
Yours is a bit different then mine. You will have different model number board.

[dfergy54]

Re: Samsung UN55C6300SFXZA won,t power up

Pulled pin 18 out of connector and applied stby through a resistor to it.
Pwr on/off then measured about 2.25 volts and relay stays engaged.
However the plus 12 volts and plus 18 V amp do not come up. They pulse up to about 8 volts and come right back down.

The chips that do the open,short,OVP and over current protection are on the bottom of the board and use the P Gnd which is approx -60 volts.

I have checked all the components FETS Transisters , large resistors and can,t find a fault.

Apparently one of those chips thinks something is out of spec and shuts down the circuits.

Anybody been here before?

[dfergy54]

Re: Samsung UN55C6300SFXZA won,t power up

I have the part numbers off all my boards I just was confused with "3066R" and "semi empty".

I,m trying to guess wehther the PS is failed or the logic/main board.
The main on this one is a little pricey. So I don,t want to add it to my collection un necessarily.

But may wind up doing just that.
These power supplys are a B#@$%! to trouble shoot.

Most switchers I just check all the actives and resistors and replavce the caps and they will go but these things are load dependant and tougher than chinese algebra.

[gary19610]

Re: Samsung UN55C6300SFXZA won,t power up

could some one help me please will not let me post a thread.i have a ps 50c96hd very hard to turn on when you can get it to turn go,s of with in 10 seconds and it do,s the clicking coming and then clicking when going of