DJM 800 Master-Out problem

Hello everybody,

i have a problem with my DJM-800: Everytime when I work with it, there is sometimes only one XLR-Out which sends a signal but after a minute the second XLR-Out sends again. After 30 minutes it goes, the Output-Signal is all the time "stereo". So I have this problem only at the beginning...

I have already changed all cables, but there is still this XLR-Out which doesn't work suddenly.

Another friend has just the same problem.

Does anynone knows something about this ? I hope you can help me...

Thanks