Welcome to the forum.
If you have no slipping or a flat spot which makes noise as it goes around I'd say your belt is fine.
I have a Beogram 3000 which predates your machine by about a decade and it's original belt is fine. B&O seemed to have the material science of turntable belts down pretty well.
cobbler wrote:Hi all,
I just inherited a B&O Beogram RX2, it is in full working order, and has a MMC3 stylus. I was wondering, seeing as it dates back to 1986, how would I know if the belt needs replacing? It had been barely used, and then stored in an attic for years, and to be fair I was suprised it worked at all, but after a bit of use it exhibits no signs of trouble at all. There seems to be no issue with playback at either speed. Can I assume all is well or is there anything I can check?