I have a samsung lnr408d that has an issue. I

Sounds like the backlight led inverter board is bad. Easy to replace. Google for replacement board.

Did you repair the power on power off switch I think that would be the only item needing replacing
I once had this same issue and went replacing the power supply board
Mine ended up only needing the power switch replaced so I got to return the board and put the old one in
Usually if you give the old board up when buying a new one a generous amount of money is taken off the new board price and this is done for any and all boards I have ever replaced in any item
I would try to see if you fixed the issue with your new board if not try the power switch that should fix the problem for less money

After you are sure you have hooked up the receiver to the TV properly and with the proper setting in the menu, if you are still having problems then you need to change the main board (the one with all the jacks on it). You will have to take the back from off the set. You will have to get the number from off the board itself and it should start with BN94-. Do a search on ebay with the part number or go to shop jimmy.com for price and availability. Also try to google search. The board is easy to change just unplug and unscrew from the panel.

Likely the whole power supply board it is shot,dying capacitors alone will not emmtting smoke out of the tv.

Howdy,
It would be a lot cheaper if you just replace the two caps that have gone bad. Just get a cheap solder pencil from the store and about an inch of solder and you are in business.
The Power Supply Board is the center Board (towards left) after you remove the back off the TV. Remove Board from TV with the 6-7 screws. Replace capacitors CM852 & CM853; 2200ufd 25volts.

Thaks for using FIXYA, BIG IRISH.

I would replace the main board (Audio/Video Board).

This is for a different model # but same manufacturer I was able to fix mine with this. I was able to get the fuse from digikey.com

My Mom's LNR408D also had sound but no picture. I was able to fix it by soldering in a jumper wire across a blown (1.5A ???) SMD picofuse on the "T-Con" board.
Consider attempting this ONLY if you: 0) Know enough to avoid the potentially fatal High Voltage parts of the power supply board!!!
1) Are a fearless hackazoid 2) know what you're doing with a soldering iron and teensie SMD parts 3) are gonna throw the busted thing out anyway so you have nothing to lose and won't be sad if you screw something up.
4) Know enough to avoid the potentially FATAL High Voltage parts of the power supply board!!!!!


This board is at the top center under a close fitting RF shield. The suspect part was labeled "CP" on the board and marked with "P" on the part. It is visible above the right-center of the connector from the main board. An ohmmeter showed it as open, so I bypassed it with a jumper wire from connector VIN to the hot side of C13. One image shows the suspect part and the jumper in place.


The other shows the TCON board placement top-center (under its RF shield). With care, it seems possible to test the fuse and put the jumper in place without removing the shield. (Obviously don't touch anything else with the VOM leads!)

Thanks to ZORBUS and Steve's TV and Electronics for the idea.
http://www.avforums.com/forums/lcd-televisions/892447-no-picture-but-got-sound-my-samsung-lcd.html
http://www.gesda.com/transformer/Fall08_files/Page336.htm
Steve C

TRY NEW JACKS AND OTHER INPUTS

I had the same problem. I live in NJ and called the local authorized "service provide" listed on the Samsung website. What a joke. Quoted $350 just to show up, never showed up. So I opened my own TV. Took off the plastic back (10 screws) took off the large metal RF shield (12-14 screws) and noticed a blown component. The markings on the component were KL15L and it is apparently an NTC Thermistor. Obviously it got fried and not knowing if there was other damage I decided to set out to replace the entire Power PCB Board Assembly and not the component. There were two part numbers on the assembled board (BN97-00457E & BN94-00622E). After searching online I also found a suitable replacement number for these (BN96-04896A). I found two places who claimed to have the part or have it on order (shopjimmy.com and vancebaldwin.com). After placing orders with both and having neither come through, I broadened my search and found out that the LNR409D was basically the same model as my LNR408D so I looked for its Power PCB Board Assembly part number which turned out to be BN41-00521B. Google search for that part number showed the item available on ebay. I bought it a week ago (ebay 260311519904) for $144 plus $12 shipping. I removed the bad board an hour ago (6 screws about 7 connectors) installed the new one, plugged in the connectors, replaced the covers, plugged in the TV... AND IT WORKS!
Suggestion: If your TV is out of warranty then open it up (what have you got to lose) and see if the problem is obvious and maybe something you can fix (replace) yourself. The parts, spare boards, etc. are out there if you look.

Sounds like a backlight going bad or possibly the inverter. Check each backlight first for dark discoloration on the ends. If that checks out good then it's the inverter.