Samsung LN46C610N1F picture/sound ok, no light

[dibsrepair]

Samsung LN46C610N1F picture/sound ok, no light

i can see a dim picture in the dark w flashlight

this is a lcd pannel

first time working on them

i have fixed a lot of led backlights

voltage table in attachment

1/12.3v
2/0v

3/12.3v
4/5v

5/12.3v
6/2v

7/0v
8/1.6v

9/0vv
10/0v

11/5v
12/0v

13/5v
14/5v

15/12.3v
16/5v

17/12.3v
18/0.8v

first time posting

cheers dan

[Andrew F. Ali]

Re: Samsung LN46C610N1F picture/sound ok, no light

We need to see the voltages on the LED connector. Measure the voltages on the +ve and -ve pins WRT GND ie BLACK lead of DMM on the chassis (GND). Report your findings.

[tvtimmy]

Re: Samsung LN46C610N1F picture/sound ok, no light

This tv has the bulbs, not leds.

[tvtimmy]

Re: Samsung LN46C610N1F picture/sound ok, no light

Try unpluging the cable that goes from the mainboard to the power supply. Check if backlights come on.

[budm]

Re: Samsung LN46C610N1F picture/sound ok, no light

Lets see the straight shot pictures of the whole top side of this power supply board.
Do you have about 380vdc reading right between the two legs of the main filter cap in the primary side?

[budm]

Re: Samsung LN46C610N1F picture/sound ok, no light

I suspect that it has bad cap CI818 (2W 474K).
Samsung BN44-00341B

[dibsrepair]

Re: Samsung LN46C610N1F picture/sound ok, no light

We need to see the voltages on the LED connector. Measure the voltages on the +ve and -ve pins WRT GND ie BLACK lead of DMM on the chassis (GND). Report your findings.

help me out here

you want the voltages from the blue and the white cable?(check attachment)

they are 0v from chassis

blue to white is 3.5v at startup drops to 0v

[dibsrepair]

Re: Samsung LN46C610N1F picture/sound ok, no light

Try unpluging the cable that goes from the mainboard to the power supply. Check if backlights come on.

Done. Backlight does not come on

[dibsrepair]

Re: Samsung LN46C610N1F picture/sound ok, no light

Lets see the straight shot pictures of the whole top side of this power supply board.
Do you have about 380vdc reading right between the two legs of the main filter cap in the primary side?

yes there is 2 caps they are inline

esr measurement says they are perfect

they are both 390v

[budm]

Re: Samsung LN46C610N1F picture/sound ok, no light

1) See post #6 to see if that cap CI818 has any sign of bulging.
2) The fuse right next to that CI818 is good, correct?

[dibsrepair]

Re: Samsung LN46C610N1F picture/sound ok, no light

1) See post #6 to see if that cap CI818 has any sign of bulging.
2) The fuse right next to that CI818 is good, correct?

yes all fuses are good

got a 65 inch lg with blown leds apart on the bench, will test caps on primary side tomorrow once i get some space on bench

[tvtimmy]

Re: Samsung LN46C610N1F picture/sound ok, no light

Pull c181i on check for any sign of a bulge on either side.

[budm]

Re: Samsung LN46C610N1F picture/sound ok, no light

The CI818 is the commonly failed cap in the inverter circuit section, it will be bulging on the sides and lost its capacitance.

[dibsrepair]

Re: Samsung LN46C610N1F picture/sound ok, no light

The CI818 is the commonly failed cap in the inverter circuit section, it will be bulging on the sides and lost its capacitance.

checked the cap and the surrounding ones

it is called cm818 on my board 10v 1000qf

they are in perfect shape

and 100% on the esr meter

[budm]

Re: Samsung LN46C610N1F picture/sound ok, no light

Nope, It is CMI818 white rectangular shape cap right next to the fuse in the middle of the board, it has '2W 474K' printed right on the top, it is Polypropylene type cap not Lytics cap.

[dibsrepair]

Re: Samsung LN46C610N1F picture/sound ok, no light

Nope, It is CMI818 white rectangular shape cap right next to the fuse in the middle of the board, it has '2W 474K' printed right on the top, it is Polypropylene type cap not Lytics cap.

found it

its bulging too

thx guys

[budm]

Re: Samsung LN46C610N1F picture/sound ok, no light

Yep, typical failure.