Samsung LN40C550J1F No power

[lilmonk3]

Hubby bought this tv from a coworker for $75 (LN40C550J1F).. He said he shut it off one evening and the next morning it was dead.. Here is what its doing.. When ya plug it in, the red power light is on solid on the front panel.. When I hit the power button on the remote, the red light goes off.. If I push the power button again, nothing happens.. That red light will only come on if I unplug the power cord and replug it in... I pulled the back off and I hear no clicks or anything.. I check the fuses and they are good.. I replaced the 1000uf 10v caps with 16v.. I dont see any flicker or glow on the screen.. Thats as far as I got, because it was bed time.. I plan on getting back to it later this afternoon.. Does anyone have some tips on where I should look next??

[lilmonk3]

Re: Samsung LN40C550J1F No power

I can get pictures this evening when I get home..

[JimmysTGP]

Re: Samsung LN40C550J1F No power

Body - Sometimes when dealing with a power cycling issue, we can easily be confused into guessing one part or another. With this symptom we really need to use "ALL" of our senses. The melody is paramount in troubleshooting this issue. Please follow the below troubleshooting guide for power cycling issues.



1. Does the unit play the melody when it turns off?

NO - This means sudden power lose and the power supply should be replaced

YES - This means the TV thinks it was turned off normaly and could be 1 of 2 parts



2. If the TV plays the melody, that means it could either be the main board or the funtion/IR pcb. Once you hear the relay to turn on, quickly remove the AC cord from the wall. Now disconnect the function/IR connector from the main board and replug the AC cord into the wall. Does the unit stay on?

NO - That indicates a main board issue.

YES - That indicates a function/IR pcb issue.

[lilmonk3]

Re: Samsung LN40C550J1F No power

No it does nothing.. I hit the power button and the red light goes out and the light wont come back on until i power cycle it with the wall plug.. "Rinse and repeat"

Body - Sometimes when dealing with a power cycling issue, we can easily be confused into guessing one part or another. With this symptom we really need to use "ALL" of our senses. The melody is paramount in troubleshooting this issue. Please follow the below troubleshooting guide for power cycling issues.



1. Does the unit play the melody when it turns off?

NO - This means sudden power lose and the power supply should be replaced

YES - This means the TV thinks it was turned off normaly and could be 1 of 2 parts



2. If the TV plays the melody, that means it could either be the main board or the funtion/IR pcb. Once you hear the relay to turn on, quickly remove the AC cord from the wall. Now disconnect the function/IR connector from the main board and replug the AC cord into the wall. Does the unit stay on?

NO - That indicates a main board issue.

YES - That indicates a function/IR pcb issue.

[JimmysTGP]

Re: Samsung LN40C550J1F No power

Just did one last week and it was his main board. If you have LED in front and no operation, then you have the same problem.

I also notice that these models are known for having faulty Mains.

[lilmonk3]

Re: Samsung LN40C550J1F No power

I have searched all day on the net, and have not had much look finding problems or solutions on this tv.. Jimmy,... One the one you fixed with the main sig board.. Did it seem totally dead except for the solid red power/standby light? Did yours make any clicks or relay sounds at all.. Mine makes absolutely no sounds or clicks.. I would think it was totally dead, if that red light wasnt on..

Just did one last week and it was his main board. If you have LED in front and no operation, then you have the same problem.

I also notice that these models are known for having faulty Mains.

[lilmonk3]

Re: Samsung LN40C550J1F No power

Ok I might be able to get my hands on the main board CHEAP and semi-Local..The problem is, its out of a LN52C530F1F.. The board numbers match to my board #. But my board has an internet cat port and a USB port and the one I can get cheap does not.. Could I possibly remove those ports from my board and solder them to the new board . The first picture should be the same one that might be able to get local, the second picture is of my board... So do you all think this would work ??

[JimmysTGP]

Re: Samsung LN40C550J1F No power

Im sure that this could be possible, as long as the option bites are changed when installed. You will need a LG Service Remote to do this properly. I have done this before only to my knowledge that the possibility of the boards numbers matching.

[budm]

Re: Samsung LN40C550J1F No power

There are two P/N on the board, one is the P/N of the blank PCB (not stuffed board), and then there is the P/N on the bar code sticker that indicated what the stuffed board with components. They do this so they can use the same blank board and stuff the board with different components for particular model/chassis/LCD panel of the TV. 52" Board may or may not work since the T-CON may use 5Vdc for power on your 40" screen, the 52" may use 12V for the T-CON. So make sure to read the DC voltage for the T-CON before you connect the boards together. The same TV model can have different brand of LCD panel installed.

[lilmonk3]

Re: Samsung LN40C550J1F No power

I went ahead and ordered the correct mainboard.. Crossing fingers thats whats wrong

[lilmonk3]

Re: Samsung LN40C550J1F No power

Jimmy.. Thank you for your guidance .. It was indeed the Main Board and all is up and running now.. Pretty nice TV for $140 total