I have a beolink 1000. After a few days the batteries are empty. I've opened it, bur everything looks "OK", I can't see anything suspicious. What's wrong?

Keypad button stuck down?  Can you check if the IR is sending constant signals by looking through a digital camera at the IR emitters.  You'll see it flashing with a signal.

See my posting 1/2 way down this thread. It is not dealing with your exact issue but it might reset/clear the issue your Beolink 1000.

Here

Good luck

Stoobie