Samsung LN55C630 Sound ok, No backlight

[alfredomfr1]

No backlight but I can see the image when I light up the screen.
Power Board: BN44-00342B

Voltage across the 450 capacitor: 163v

Any help troubleshooting this would be appreciated.
Thanks guys

[budm]

Re: Samsung LN55C630 Sound ok, No backlight

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

Report the DC Voltage readings on CN802.
Pictures provided by SHOPJIMMY.

[alfredomfr1]

Re: Samsung LN55C630 Sound ok, No backlight

CN802: 0v

[tom66]

Re: Samsung LN55C630 Sound ok, No backlight

On every pin....? Are you sure?

[alfredomfr1]

Re: Samsung LN55C630 Sound ok, No backlight

Sorry my mistake
CN802
Pin 1: 12.58v
Last 2 pins: 9v
0v in the rest of pins

[budm]

Re: Samsung LN55C630 Sound ok, No backlight

That is still not right, that connector has double-row of odd and even pins.

[alfredomfr1]

Re: Samsung LN55C630 Sound ok, No backlight

In order to measure CN802, I disconnected CNI801 AND CNI802
CN802
1,2,3: 12.62v
4,5: 0v
6,7: 5v
8,9: 18.85v
10: 0v
11: 5v
12: 0.78v
13,14,15: 0v
16,17: 5v
18: 0.8v

[alfredomfr1]

Re: Samsung LN55C630 Sound ok, No backlight

Sorry another mistake in the last post
this is the right pin out
1,3,5: 12.62
7,9: 0
11,13: 5v
15,17: 18.85
2: 0v
4: 5v
6: 0.78
8,10,12: 0v
14,16: 5v
18: 0.8v

[alfredomfr1]

Re: Samsung LN55C630 Sound ok, No backlight

Any Help?

[budm]

Re: Samsung LN55C630 Sound ok, No backlight

OK, not sure about pin 18 which receives POWER ON/OFF command from the main board, it looks like it is active LO (LO (<1VDC) = ON because all the Voltages are present.
The backlights inverter on (pin 4) is present, this voltage should be <1V when TV is turned off, please verify.
Also the dc Voltage at the two legs of the main filter caps shouLd jump up to 350~400VDC if the PFC Voltage booster is working, the backlights inverter circuit needs this high voltage to function, if that voltage is staying at 160V, then we will need to look deeper in the PFC CIRCUIT. I hope you do have all the proper tools to work on this board at component level.

[alfredomfr1]

Re: Samsung LN55C630 Sound ok, No backlight

Good morning budm
I'm ready to work in the PFC circuit
Thanks for your help

[budm]

Re: Samsung LN55C630 Sound ok, No backlight

So, you did not see the boosted voltage on the main cap, right?
Your bottom side of you board matches this picture?

[alfredomfr1]

Re: Samsung LN55C630 Sound ok, No backlight

No boosted voltage and yes same board

[alfredomfr1]

Re: Samsung LN55C630 Sound ok, No backlight

Remember that CNI801 and CNI802 are disconnected

[budm]

Re: Samsung LN55C630 Sound ok, No backlight

Remember that CNI801 and CNI802 are disconnected

That is fine, that will not affect the PFC.

[budm]

Re: Samsung LN55C630 Sound ok, No backlight

Can you read the number on top of the PFC IC ICP801? We need to get the spec sheet to get the pin out of this IC.

[alfredomfr1]

Re: Samsung LN55C630 Sound ok, No backlight

Fan7530

[alfredomfr1]

Re: Samsung LN55C630 Sound ok, No backlight

Black point of the multimeter connected to the chassis of the tv and taking measure with the red point on FAN7530, all pins read less than 0.1v

[alfredomfr1]

Re: Samsung LN55C630 Sound ok, No backlight

Hi guys I need help with this TV can we continue with this thread. Thanks in advance

[tom66]

Re: Samsung LN55C630 Sound ok, No backlight

So, was that measurement with the TV powered on, board plugged in to main board & AC power?