Since yesterday, my 5 year old Samsung LCD TV won't turn on anymore. The screen (backlight) just turned on for ~0.1 second and after that the TV started repeatedly to turn on/off without turning the LCD/backlight on. I can hear the relay and the standby led turns red / off repeatedly. After investigating the problem by searching on the web, I found that more Samsung LCD tv's had about the same problem. But it seems my problem is different.
First, here is a video that shows the symptoms:
Forums on the web told me that probably the power supply of the TV is broken, caused by leaking/defective capacitors. Unfortunately, after opening my tv, I found out that the capacitors were just fine. It actually has 2 of the suspicious capacitors on the power supply board, but they seem to be fine (no leak, damage, bottom bung pushed out etc). Also when testing with a multimeter, the resistance increased normally, just like a similar capacitor I have here.
My intuition tells me that it is still something related to the power supply board, so the next step I think of is buying a replacement psu board. However, because there are discussion boards like these (), I hope people can help me further in finding the cause of the problem. I'm not a specialist in TVs, but I have a technical background and soldering is no problem for me. Are there things I can test further, or does anyone recognizes this problem and knows what to replace? If more information is needed, please let me know!
(This post was edited by Tutti-frutti on Oct 1, 2010, 5:23 PM)
usually if the back lights come on for a second then shut down, it's a bad lamp in the lcd panel, and the whole lcd panel needs to be replaced.
In Reply To
Or a bad winding on an inverter transformer. Or cooked electrolytic capacitor(s) on inverter (or power supply) board.
Thank you for your replies. The backlight turned on just for just a fraction of a second before the TV started to repeatedly 'trying' to start up. So it was only once that the backlight did this. I don't know if the symptoms as shown in the video are normal if there is a failure in the inverter or backlight? Tonight I would try to replace the -on the outside- normal looking capacitors, but my guess is that the problem is caused by something else. I'll post the result.
As expected, new capacitors didn't do the trick . Are there things I can test/measure to bring me closer to the cause? Otherwise, my last hope is a replacement of the power supply board.
Unplug set take back off unplug the lvds cable from the T-Con plug in set. Does it turn on? If yes replace T-con. If no . . . unplug set unplug lvds cable from main board plug in set. Does it turn on? If yes replace cable. If no replace main pcb. Good luck to you
Eventually, it was a 82k ohm resistor on the main powerboard that was broken (the picture in the TS is of the sub powerboard for standby power.. oops). <br>I didn't find out myself, I brought it to a local tv technician, which diagnosed and fixed it for 60 euros. Happy again :) <br>
(This post was edited by Tutti-frutti on Jan 25, 2011, 12:28 PM)
FORUM
SEARCH
WHO'S 
LOG 
RULES
), I hope people can help me further in finding the cause of the problem. 
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Unplug set