Welcome to the forum. I'm not very familiar with the exact model you noted here (686), but do you know if it has the Auto Motion Plus feature? If it does, try toggling that to a different setting to see if the issue goes away.
Keep me posted.
I have purchased a samsung 40" 686M TV, and a BD-P1500 Blu ray player.
I am having a slight issue, and that is when the blu-ray outputs a signal at 1080p (50hz) I would describe as a slight shudder and flicker. If I cycle through the source inputs it does away, likewise if I set the output signal to 1080i the shudder and flicker go away.
I've tried two different HDMI cables which has not aleviated the problem. Does anyopne have any ideas on anything I can do to get rid of the problem? Or do I need to call out an engineer?