Chosen Solution
I am troubleshooting a Sony KDL-75W850C per the service manual. 6 red blinks indicates either bad power board or LD panel. I have checked power board and I have good 3.3v STBY, 12V, and BL_ON. . It says I need to measure the LED output voltages. I assume I measure them between OUT+ and OUT- on the board. All the other points are measured to Ground. The reason I ask is I get a brief pulse of 132V between OUT+ and OUT- then it collapses to 0. If I measure between OUT+ and Ground I get varying voltages from 0 to 200V ( I assume a cap is charging discharging).
There is an LED or two that are out on one or more of the strips. You will need to test the strips and/or the LEDs to locate the one(s) that don’t work. A single shorted LED can cause this. Please note that there are protection circuits that shut down the LED supply to prevent further damage. This is why you see the short pulse of 132V. Dan
