Question about Samsung LN40A450 LCD TV
I have a samsung LN40A630. Backlight doesnt turn on, and the red light blinks intermittently. All of the capacitors on the PS board are metering at proper voltage when I apply AC power to the board. I can't find any error codes online for the blinking light. Please help.
These blinks are fault indication, and known as blinking codes. From the number of blinks occur at one time switch ON; you can get an idea about the faulty circuit stage inside the TV. This will make repair easy. For more information, check the link http://electronicshelponline.blogspot.com/
Posted on Dec 02, 2013
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.
Posted on Nov 16, 2008
Replacing the capacitors would be a good start. Replace all the ones with the same capacitance and voltage rating even if they do not look bulge.
Let me know if you require further assistance.
Posted on Mar 14, 2009
Apparently this is a known problem with flat panel TVs made a few years ago due to bad capacitors in the power supply. This same problem appeared in computer mother boards at about the same time so that the capacitors went open or shorted causing problems.There is videos on You Tube that addresses this problem see: http://www.youtube.com/watch?v=ZccykxrtX9g as a starting point and look around for other repairs
Posted on Jan 25, 2011
The issue you describe is consistent with a power supply board issue. This is the board where the AC goes to. This problem may have occurred as a result of irregular power supply, or excess power supply or power surge.
The TV is receiving current but cannot circulate or transfer the current to other necessary part of the TV because of the defective power supply board. You might be lucky it's just a blow fuse. Also a defective transformer can cause your TV not to power on.
All these can be checked on the power supply board.
But more often bad capacitors causes problem on the power supply board. I do not think the power board needs replacement, rather those defective capacitors is causing this issue. Open unit up and take a look at the power supply board.You will probably see one or more electrolytic filter capacitors that are bulged up in the top-not perfectly flat like the others.
The value of these capacitors will be different, most likely they will be somewhere around-820 to 2200uF/25 V( or /10V sometimes)
You can replace them with same values but I would recommend the voltage rating to be higher(like 35V for an original 25V) for reliability purposes.
What happens is,these bulged top capacitors will cause a low and unfiltered DC voltage=main board will malfunction(the relay will keep clicking until the caps are holding enough charge to bring the voltage up over a threshold point).
You can buy these capacitors at any Fry's or Radioshack store or you can order them online at vendors like "mcmelectronics.com"(look for electrolytic capacitors). After replacing these capacitor(capacitors) most likely the normal operation will be restored. Or you can by a refurbished complete power board to save you some stress.
Note: There may be also some other causes for this symptom ,like a defective T con board ,or main board,but the bulged top capacitors are the most common cause for this issue.
If you don't know about TV repairers, take the TV to the nearest repairman to fix the fault for you. Also, note that TV stores a lot of current, so wait a while before opening the TV back cover.
I hope this helps.
Posted on Jan 05, 2012
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