samsung UN46c5000QF

[tom66]

Re: samsung UN46c5000QF

Great, I have schematic


Backlight SHOULD be on with main board disconnected
Can you see CNL801? Please test voltage from first to last pin.

[martino]

Re: samsung UN46c5000QF

I did 3 tests...cn201 plugged in tv off/tv turning on and cn201 unplugged.
There are only 4 wires in the 8 pin connector,pin 1,4,5 and 8 have wires..
pin 2,3,6 and 7 have no voltage in any test...

cn201 plugged in,TV OFF:
P1 to P8 =zero voltage..

cn201 plugged in,TV ON:
P1=190v
P4=95v
P5=95v
P8=19.5v

cn201 UNPLUGGED,power to TV:
NO power on any of the 8 pins...

The reading of 190 etc only stayed on for less then a sec while attempting to turn TV on,then back to zero volts..Spikes just long enough for multimeter to catch up to the readings I got...

[martino]

Re: samsung UN46c5000QF

Now pin#1 voltage is a half rectified dc power,correct?? (diode D9102)
I measured this with MM on DC 200 volt..
I cant see on scematic where pin 4 and 5 connect too...
Is this the proper voltage going to the backlight? I hope not cause that would mean the screen is passed away???

[martino]

Re: samsung UN46c5000QF

I tested the voltage with the black lead on the chassis. Reading forums here,when on the HOT side you need to take a negative pole from a cap..
This 190 v im measuring is that considered "HOT" or is it on the cold side???

[tom66]

Re: samsung UN46c5000QF

What do you see across C9114, the 8.2uF 400V capacitor, as it powers up?

[martino]

Re: samsung UN46c5000QF

180.4 volts...again only for a second....

[tom66]

Re: samsung UN46c5000QF

This is because the BL ON signal is going away. The main board is turning it off. As far as I know, there is no feedback signal from the backlight circuit to the main board. The main board can't tell if the backlight failed to work and should continue operating (e.g. boot sound, tv sound, power indicator working) even if the backlight didn't. This is why I think the main board is bad. Did you try EEPROM reset outlined previously? Try to look for 8 pin devices marked 24C16, 24C32, 24C256 etc.

[martino]

Re: samsung UN46c5000QF

Didn't reset eeprom yet...tried to find it comparing it to the pics from the link you send me but didn't see a board similar to this one...

The powersupply failing to turn on backlight with mainboard unplugged made me to focus on powerboard more...
I will try to find the eeprom now

[martino]

Re: samsung UN46c5000QF

Going to town to pick up 2 more tv's and I will stop in in walmart to buy a magnifying glass,cause I can't read those tiny numbers

[martino]

Re: samsung UN46c5000QF

Bought me a super handy magnifying glass with light in it,works great ..!!
Back to business,I checked every 8 pin IC/devise on the main board,even had my better halve scan for it,but we can't find a single one with 24c..... printed on them..
We even went ahead and checked all the Ic's with more pins...no luck...

[martino]

Re: samsung UN46c5000QF

Took mainboard out and looked at back side..No IC etc but did see some copper colored points that had printings beside it,like main eeprom-wp etc..
One point is labeled STB_NRESET...Could any of those be needed for a eeprom reset??

[tom66]

Re: samsung UN46c5000QF

Yes, reset can probably be achieved by connecing MAIN EEPROM SDA, SCL and GND all together.

[martino]

Re: samsung UN46c5000QF

Yes, reset can probably be achieved by connecing MAIN EEPROM SDA, SCL and GND all together.

ok,connect them all together,then power up tv? does mainboard need to be attached to chassis(ground through screws)??
I took it off chassis to look at back side,I'm guessing it would be best to solder wires on those points???
So,to be clear,I solder wires to those points,screw it back to chassis,then apply power to tv,do I need to do startup attempt? if i do,just once or multiple times??

[tom66]

Re: samsung UN46c5000QF

Yes, TV must be off, then jumper the pins, power up (using button or remote), release after about 10 seconds.
If set does not boot up, then it is probably a firmware problem. You can also try with SUB_EEPROM_SDA, SCL, GND...

[martino]

Re: samsung UN46c5000QF

I'm guessing it won't boot up during the reset cycle??
So,do the reset cycle,then take jumpers off and try turning on tv?? is that correct??

[tom66]

Re: samsung UN46c5000QF

According to the SAMYGO website, it should boot, with a message asking you to set the default parameters...

[martino]

Re: samsung UN46c5000QF

tried the reset procedure....
tried with sda,scl and ground in all combo's..
tried to power up for 20 sec with remote,tried with just leaving it in standby for 20 sec etc...
No live whatsoever

I'm guessing I will be buying a mainboard now????

[tom66]

Re: samsung UN46c5000QF

That would probably be the only fix.

[martino]

Re: samsung UN46c5000QF

I will try and get one,lot's of places "out of stock",meaning they go lot's?? lol
Also posted in "wanted to buy" here on the forums...
Will post back when I get one....thank you very much for all your help so far

[martino]

Re: samsung UN46c5000QF

So,I finally got a mainboard for the TV.
Installed it and................no go
I tried standby,mute,1,8,2,power on.....no go.
Now,having learned a few things from here,I went a head and jumped pin 16 and 18 with a 1K resistor on connector CNM801.
Then I plugged in the TV and the backlight came on,but flashed in 1 sec intervals 10 times and then goes dead.
Now I'm a little stuck Any suggestions?