TV will not turn on, no standby light
My samsung UN49MU6290 TV will not power on and will not show a standby light. I replaced both the power board and the main board. When I disconnect the cable going from the power board to the main board then the backlights will turn on. I checked the voltage from the power supply and the chart says it needs to be 12V and when I have it disconnected from the main board it will show the correct 12v but when I have it connected to the main board it shows 9v. I am not sure what to do next.