Samsung LN46C530 No Picture

[dreadnok]

I have a Samsung LN46C530F1FXZC that when I turn on will make the power-up sound and then the red light goes off but I do not have any picture.

My power supply board is BN4400418A. I replaced 7 caps on the power supply board on spec. (CM801, CM805, CM809, CM811, CM813, CM815, CM818, CM820)

If I remove the connector CN802 on the power supply board and plug the TV in the backlight does not turn on. (I do not see any change on the screen or notice any light showing on the back of the TV)

My problem seemed similar to this post.
https://www.badcaps.net/forum/showthread.php?t=25665

When I tested the voltages on the power supply board at connector CN802 I get
Pin 1 - 12.43V
Pin 2 - 12.43V
Pin 3 - 12.43V
Pin 4 - 0V
Pin 5 - 0V
Pin 6 - 5.174V
Pin 7 - 5.174V
Pin 8 - 12.43V
Pin 9 - 12.43V

When I test the voltages on the power supply board at connector CNI802 i get
Pin 1 - 12.35V
Pin 2 to 5 - 0V
Pin 6 - 8.87V
Pin 7 - 8.87V (The person in the other post had 10.98V on pin 6 and 7)

I tested both sides of the fuse on the T-Con board and I got 12.38V.

I ordered a replacement T-Con board. I swapped it out and I still have the same issues. Any advice on what to look at next?

[bammbammfran]

Re: Samsung LN46C530 No Picture

you might have a problem on the inverter board.
pin 6 and 7 could be dimming pins, so that could be why they are different.
If you have a ohmmeter, check the main fuse F1
on the inverter board to see if it is showing zero.

there is also a fuse near the middle of the power supply that might be feeding the backlight transformers
check that for power at both ends

[budm]

Re: Samsung LN46C530 No Picture

This TV uses power supply-inverter board combo (as shown in the picture in the link), the high voltage from the inverter section feeds the Balancer board. Can we see the pictures of YOUR boards?
If the Inverter circuit works at all you should see the backlights flash on for seconds then it will go into shutdown if error is detected. Do you see it flash at all?

[dreadnok]

Re: Samsung LN46C530 No Picture

I do not see a flash at all.

Here are pictures of my boards.

[bammbammfran]

Re: Samsung LN46C530 No Picture

with you tester set to 200+ dc
power on and check for voltage at both the double red circles using you positive pin on red and negative pin on the green circle

if that is ok
check the other two red circles (green as ground again)

[dreadnok]

Re: Samsung LN46C530 No Picture

with you tester set to 200+ dc
power on and check for voltage at both the double red circles using you positive pin on red and negative pin on the green circle

if that is ok
check the other two red circles (green as ground again)

Both sides of the fuse (double red circles) measure 391.2V.

The other single red circles, the one on the left side Q1802 measures 391.2V the one on the right QI808 reads 1.8V

[budm]

Re: Samsung LN46C530 No Picture

We need to find out first if the main board is sending the SW_INVR (bl_on, on/off, ot INV ON) signal to this pwr-inver board or not. There should be some kind of the labels on the pwer-inverter board connector that goes to the main board.

[dreadnok]

Re: Samsung LN46C530 No Picture

We need to find out first if the main board is sending the SW_INVR (bl_on, on/off, ot INV ON) signal to this pwr-inver board or not. There should be some kind of the labels on the pwer-inverter board connector that goes to the main board.

On the power supply board it shows that SW_INVR is on the bottom row of the connector pin 2. (Connector between Main Board and Power Supply Board has 2 rows of 18 pins) Can I disconnect the cable at the power supply boards and measure that pin? I can not get at the pin when it is connected.

[bammbammfran]

Re: Samsung LN46C530 No Picture

since the connector needs to be connected while you are testing these.
pin 4 and 6 are the inverter dim and on/off and you either have to get readings from the bottom side
or find something thin like a sewing pin to slide into the wires connector along side the wire to get a reading
or see if you can see those two lines on the main board side

[dreadnok]

Re: Samsung LN46C530 No Picture

The pin on my power board labeled SW_INV reads 0V when the TV is plugged in but off. When I turn on the TV i get 5.168V.

Here is a shot of the signals available on the connector.

[bammbammfran]

Re: Samsung LN46C530 No Picture

sounds right and it leads to the red mark I have on the attached picture
But we will need a good clear picture of you actual board showing the same area as my picture is showing to try to see if you have any obvious issues in this area that runs the inverter side

[dreadnok]

Re: Samsung LN46C530 No Picture

My Board

[dreadnok]

Re: Samsung LN46C530 No Picture

bump

[jeffer76]

Re: Samsung LN46C530 No Picture

I am curious what the value of the capacitor at cm806 on the power supply is? Could someone please help out. Its in the middle of the long shield between icm801 and dp802.

[budm]

Re: Samsung LN46C530 No Picture

Can you read the P/N of the IC ICM801? That CM806 is the snubber cap connected between the Drain and Ground (Source) for the ICM801.
Is the IC P/N FSGM0465R? If it is, then the cap is 100pF 1000V or higher.

[gdawg]

Re: Samsung LN46C530 No Picture

I know this is an old post but could you tell me if this issue was resolved. I picked up the same set with no back light on. All voltage readings good but I dont hear anything from the inverter transformers. I appreciate any results. I was going to buy a power supply but I always try to fix component level. Thanks

[gdawg]

Re: Samsung LN46C530 No Picture

Fixed!!! Cap c1818 was the problem. power supply board