Chosen Solution
Hi People! Please, note that my TV is UN55KU6490 and not the UN55MU6290 *** I have a defective Samsung TV UN55KU6490. The PS board is BN44-00807A and the main board is BN94-10827Q. There are only these two boards. The screen is always black. Whenever it is powered-on, I can hear a weak sound on the speakers, like the Samsung “Welcome” sound; it happens only once. The back panel LEDs cycles Full On -> Dim -> Off, in cycles of about 10s. I download the service manual from a similar model, and I was able to go through some tests: On the PS board:Disconnecting the cable between the PS and Main board, all the back panel LED lights up, stay on, and I could measure 266Vdc and 132Vdc on CNL802 connectorThere is the 12.8Vdc.While the TV is on Standby, it is steady at 12.8V;When the TV is Powered On, it stays at 12.8V and quickly drops to 8V about every 10s.On the Main Board:I could measure the voltages on the joystick button, and they change accordingly (0; 0.5V; 1V; 1.5V; and 1.8V)The is 5V on the USB portsI’m not 100% positive about it, but it seems the PS_ON keeps at 3.3V and quickly drops to around 2V, following the 10s cycle. It is pretty awkward to measure this signal (at least to me…). Following the service manual, it looks like the defect is on the Main Board. Is it correct? Any other test that I should do? Any tips? Finally, what is a good site to buy the board (refurbished / used)?
I’ve added some pictures from the boards.
Thank you!
masiyagu+cnd your power board is okay. Glad you tested that. This does sound like a main board issue the only thing that is weird is this “Welcome” message. Does it sound like it did before? I would focus on the main board. Post some good images of your boards and the interconnect cables with your QUESTION Adding images to an existing question That way we can see what you see.
