Chosen Solution
Hello, I have a 60” Samsung led TV model un60j6200afxzc. When I plug the tv in it keeps making a poping noise every few seconds, then turns off. I opened the back, checked the power board for bulged or leaking capacitors, and no cracked solder joints either. I tested the mosfets, no shorts, main fuse is good, diodes all tested okay too. With the back off it sounded like it’s coming through the hole in the Frame where the wires go to power the led strips. I unplugged the connection from the power board to the leds and it stopped popping, in fact the sound started working so I shined a light through the tv and discovered the screen works so…. I know it’s my backlight power circuit on the power board or the leds them self. With the L.E.D unplugged from the power board I did the following tests. Mosfet DM851C is circled on the board and has white writing on the board pointing to the middle pin saying: STB: 8v ON: 13v I tested the ON voltage and it read 12.8v The standby voltage is way off… in about 3 seconds it climbs from 0v to about 190V before it goes overload then back to 0v and repeats. is my board toast? I also tried testing the Two + leads on the board where the led plugs into, but with the L.E.D unplugged because it’s the only way I can keep it on to test it and with my neutral grounded to the frame. There are only 2 sets of wires going to the L.E.Ds #1 pin which is D+ reads: 349v in standby Mode 421v in On mode #6 pin which is S+ does the exact same thing in both Standby, and On it is the exact same thing as my standby voltage on the MOSFET I starts at 0v climbs to 190 before it overloads my meter and goes back to 0v and repeats every 3 seconds I would like to point out that 0-190v cycle also appear to coincide with the poping from the led backlight when it was plugged in. I don’t have a LED tester but I did try a continuity test on the male end of the Backlight plug to the power board, no continuity’s any help would be greatly appreciated. I don’t want to buy a new power board then find out it was a small part causing the issue or that the LED are burnt out too.
Hi, Go back to basics and try the following. Disconnect the power from the TV and then disconnect the cable between the mainboard and the power board. Ensure that the LED backlight cable is connected to the power board. Reconnect the power to the TV. The TV backlights should turn on full intensity and stay on. If the backlights blink or don’t come on at all, then there is a problem either in the power board, the cable/cable connection to the LEDs or in the LED strips. Measure the voltage between the LED + connectors and earth. If the voltage is >310V DC then there is an open circuit, either in the cable or in the LED strips. The power board is driving the voltage as high as it can trying to turn on the LEDs. If the voltage is <80V DC then the problem is in the power board. Also measure the voltages at the connector where the cable from the mainboard was connected, to see if they are as printed on the power board near the connector.
