Welcome to the forum, contact Dillen on the forum, he normaly has the correct belt for Beograms, he gets them specially made and they fit.
Here and chose start a conservation with Dillen
Beosound 3000, BL 4000, BL 8000, BG 2404,BG 5000, BG CD50, Beocord 5000, BM 901, BM 2400, BM 4000, BV S45, BV 3702. There is nothing we cannot do, but a lot of things we don't want to do!!