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Anthony, Engineer
Category: Printers
Satisfied Customers: 14767
Experience:  Sharp Panasonic Hitachi business products engineer
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I have a 40" Samsung LED TV (LA400550K) that seems to have

Customer Question

I have a 40" Samsung LED TV (LA400550K) that seems to have suffered a power surge or something. When I press the touch sensitive buttons in the front, they red light turn on, giving the impression the TV is turning on, but nothing ever come up on the screen and no sound no picture comes out of the TV either.Any suggestions as to what it may be or what parts might need to be replaced? (bought new power board changed still not working)
JA: Just to clarify, what's the LED television's exact make and model?
Customer: Samsung type # LA400550 model code LA40D550K1JXZK version # CN01
JA: What troubleshooting have you tried?
Customer: No sound No picture suddenly power off, we changed working power board still not working. I think maybe main board or other parts? (opened rear cover have two board inside)
JA: The TV expert can solve this for you. Anything else you want him to know before I connect you two?
Customer: my email address:***@******.*** we live in Hong Kong
Submitted: 1 year ago.
Category: Printers
Expert:  Anthony replied 1 year ago.



So just to clarify you are stuck with the red light on the front of the set ,the set wont unlock and come on with either the remote or the front buttons on the set itself, you have replaced the power-board with the correct replacement board still the exact same fault is that correct?


Customer: replied 1 year ago.
we replacement same type model power board still not working sound & picture.
Expert:  Anthony replied 1 year ago.

You need to get the back off the set, locate the mainboard thats the board with all the AV connectors on,now take the board out by unplugging it and unscrewing it from the chassis,look on the board for the part number this will be on a sticky label or etched on the board (you may need to try different codes on the board) then google this number looking for suppliers.

The mainboard "unlatches" the power-board with a command if it does not do that because its control data is bad or it develops a hardware issue on the board it will lock up and the set will be stuck in standby

Let me know if you need more help

Please consider rating the answer positively with the rating bar of stars at the top of the page, rating me positively enables me to receive payment from the site thank you, ***** ***** question is open for 30 days

Many Thanks


Let me know if you need more info

Customer: replied 1 year ago.
Attached picture for your reference. replaced power board its good works
Customer: replied 1 year ago.
any possibility idea main board (AV board) faulty?
Expert:  Anthony replied 1 year ago.

Sorry I don't understand what you men?if you mean is there a way of verifying if the board is bad then no as the board is a data board there is no way to check a board like that, you need to use the part-number though found on the board itself that is very important as there may be variants of the board in the same model that will not work

Please remember to rate positively thank you


Expert:  Anthony replied 1 year ago.

Just to add if you are getting exactly same symptms with original power-board then I am assuming the power-board you have fitted is good the chance of it being main-board now that you have done that is 95% so I have little doubt a replacement mainboard will work


Expert:  Anthony replied 1 year ago.

Do you need any more help with this please?


Customer: replied 1 year ago.
this model LA400550K samsung tv without power board what's parts were always faulty.
Customer: replied 1 year ago.
as picture my tv right hand side with black plastic cover what's parts inside?
Expert:  Anthony replied 1 year ago.

Sorry i do not understand what you are saying.....

Customer: replied 1 year ago.
Can you find the main board for me or where to buy?
Customer: replied 1 year ago.
main board sticker barcode # CN10 BN91-06679C
Expert:  Anthony replied 1 year ago.

The part-number looks like the BN-06679C but please re-check it as nothing is coming up, you are in the far east so you will need to get the board from there as the firmware that runs the board will be different in any other country


Expert:  Anthony replied 1 year ago.

I am in the UK so I have no knowledge of suppliers in HK or China however googling the part-number always brings up suppliers

Expert:  Anthony replied 12 months ago.

Do you still need help please?

If not i would be most grateful if you would rate the answer\info positively with the rating bar of stars at the top of the page thank you, ***** ***** allow me to receive credit from the site thanks again