Samsung LN32C540F2D NO Power No Red Light

[techrat]

I have the subject TV that does not power up and has no red power light. So far I have taken the back off and visually inspected all components on the main board and power supply board with everything looking OK. With the main board plugged into the power supply, nothing happens when plugged in.

If I unplug the main board and and attach the TV to power, the back light comes on.

Based on something I read on a similar post, I checked the 1117 regulator on the main board and found no voltage on any of 3 pins. Not sure if this test means anything but thought I would mention it.

This is as far as I have gotten so far. I look forward to any suggestions for further testing.

Thank you- Jeff

[budm]

Re: Samsung LN32C540F2D NO Power No Red Light

OK, you are on the right track, the power supply and the backlights inverter boards are OK.
Can I see good closed up pictures of the white connectors? Trying to find out which one is from the power supply board. Also the picture of how all the board are connected together.
Also pictures of the regulators.

[techrat]

Re: Samsung LN32C540F2D NO Power No Red Light

Almost Midnite here. Will take some good pictures tomorrow and post them. Thanks!

[Hobby 1]

Re: Samsung LN32C540F2D NO Power No Red Light

look up this post: Samsung LN40C540 Turns on when it wants to...
It is for a 40 inch version, same problem. It is probably the main board. You can replace it with the next version board if you can't find the same original board.

[Hobby 1]

Re: Samsung LN32C540F2D NO Power No Red Light

Change out the caps on the power board while it is open and save a future repair also.

[techrat]

Re: Samsung LN32C540F2D NO Power No Red Light

Added some additional pictures may have to post a second reply to get all of the pictures requested. I appreciate everyone's help.
-Jeff

[techrat]

Re: Samsung LN32C540F2D NO Power No Red Light

Here are the best close ups I can get of the regulators with the lighting I have available.
Thanks Again!

[budm]

Re: Samsung LN32C540F2D NO Power No Red Light

OK, If you look at the regulator IC with the big tab up and call left pin as pin 1, middle pin (same as the big tab) for #2, right pin for #3.
Take the DC voltage readings on each pin, black probe of the meter to the chassis for secondary side circuit ground ref. Report the readings.
I have a feeling that it will not be the regulator problem, may have to replace the board instead of fixing it.

[techrat]

Re: Samsung LN32C540F2D NO Power No Red Light

look up this post: Samsung LN40C540 Turns on when it wants to...
It is for a 40 inch version, same problem. It is probably the main board. You can replace it with the next version board if you can't find the same original board.

Looking for a main board now just to be prepared. Wondering how to interpret the part numbers. Can anyone tell me what the next version board would be or a list of compatible part numbers?

Thanks,
Jeff

[budm]

Re: Samsung LN32C540F2D NO Power No Red Light

Use the P/N on the barcode sticker and also the little one on the left side of the board, BN96-XXXXX, try shopjimmy yet? He can guide you to the correct one.

[Hobby 1]

Re: Samsung LN32C540F2D NO Power No Red Light

Go to ebay. Enter in the model number. See what is available. Try the next size up. It uses the same board. Try the next model up (550). If you 'upgrade' you will need to cut out new holes for the extra inputs. Compare the actual picture with your board. It does not have to look exactly the same, just has to come from the same model. There are at least 2 versions of the main board. They are interchangable. I upgraded mine from a 540 to a 550, 2 extra inputs. Prices from $50 to $100.

[techrat]

Re: Samsung LN32C540F2D NO Power No Red Light

OK, If you look at the regulator IC with the big tab up and call left pin as pin 1, middle pin (same as the big tab) for #2, right pin for #3.
Take the DC voltage readings on each pin, black probe of the meter to the chassis for secondary side circuit ground ref. Report the readings.
I have a feeling that it will not be the regulator problem, may have to replace the board instead of fixing it.

Ok so no voltage on any pins. So I thought Iwould verify the voltage on the cable coming in from the power supply. When plugged into the main board, the row of pins accessible from the top have no no voltage at all however when I unplug the cable from the main board the cable has voltage . Plug it back into the main board, no voltage. Maybe this is expected behavior. I dont know. In any case, the regulators definitely have no voltage on any pins.

I'll keep at it.

Jeff

[budm]

Re: Samsung LN32C540F2D NO Power No Red Light

So you are not getting the 13v or the 5V on CN802 of the power supply board?

[techrat]

Re: Samsung LN32C540F2D NO Power No Red Light

So you are not getting the 13v or the 5V on CN802 of the power supply board?

I am getting the correct voltage on these pins, on the power supply board at CN802 but only when the Main Board is disconnected. As soon as I plug in the main board, all of these pins drop to 0 volts. I don't know if this makes any sense at all but it is what I am experiencing.

Is there anything else I should test?

[budm]

Re: Samsung LN32C540F2D NO Power No Red Light

KIt sounds like the main board shorted out the power supply outputs. Need to find the diagram of that main board so we can Ohming out the resistance.

[techrat]

Re: Samsung LN32C540F2D NO Power No Red Light

Anyone on board have any idea if either of the following boards will be an acceptable replacement for the suspect main board I have?

http://www.ebay.com/itm/SAMSUNG-LN46...item2c6978d201

http://www.ebay.com/itm/Samsung-LN32...item53ef4fe3d9

My part number is BN96-14763A v1007A

Thanks!

[tom66]

Re: Samsung LN32C540F2D NO Power No Red Light

Ask the sellers what panel the TV used. Many keep this information. If it is the same, you may be in luck. Careful with the extra ports though. You may have to cut a hole to support them, they may otherwise prevent you securing the case.

[Hobby 1]

Re: Samsung LN32C540F2D NO Power No Red Light

Either one will work but if you use the one with the extra connectors (convert your set to a 550), you will have to cut through the plastic label on the back of the metal cover. The metal cover has the holes already punched out but they are covered by the label. Use a sharp X-acto knife and cut just a little inside the punched out metal hole. One for the Lan connector and one for the extra USB connector.

[techrat]

Re: Samsung LN32C540F2D NO Power No Red Light

So I did a little more investigation on my TV. What I did was went through all of the pins on the connector in between the Main Board and the Power supply board and tried to isolate which pins, when connected result in the backlight going off and the power at the connector dropping to 0. So here is what I found:

The PS_ON pin when connected results in all of the voltages at the cable between the power supply and the main board go to zero. If I disconnect the PS_On pin, the voltages at this connector all stay at the "appropriate" level.

If I leave the PS_ON pin disconnected with all other pins connected, the backlight goes off when I plug the connector into the main board.

If however I leave the PS_ON pin, the E-PWM pin and the BLU_ON pin disconnected, the back light will remain on when I plug the connector into the main board.

The last variant is: PS_ON connected, E-PWM & BLU_ON disconnected, the backlight will kind of flicker a little bit then go off.

I don't know if any of this is usefull for diagnosis but I will appreciate any feedback.

Jeff

[budm]

Re: Samsung LN32C540F2D NO Power No Red Light

OK, I am confused, I thought you lost ALL the voltages, especially the 5V and the 12V? If you do do still have the 5V, then I can explain what you are seeing at the PS_ON and the BL_ON pins.