I have a Samsung DMR78AHS that's recently developed a fault. It runs normally for a while then gets into a state where it pauses for a moment, beeps, beeps again, and starts back up, while flashing the screen on and off. It does this both during the wash and rinse cycle. Eventually it finishes the cycle, but it makes a 3-hour "heavy" cycle take about 6 hours and the dishes don't get clean. I took a short video of the behavior: https://www.youtube.com/watch?v=G9BWgvqI_iM
I ran it through the tests in the service manual and everything seems to function normally. It's almost like it thinks the door is being opened and closed during the cycle, but it seems normal during the service mode, where if the door switch were flaky it should show up there.
Anyone got any thoughts?