Hi. I just commented on another topic, but I think it’s the same issue so here is the post.
I just bought 2 used Eurolive B215D where there was no bass. The tweeter was working fine. I found the cause so I hope other might find it usefull. I pulled out the amp module and disasempled most of it. On the amp circut board there was a lose coil, which must have gotten lose due to rough handling. So I just repaired the coil and glued and soldered it back (used epoxy glue to make sure that it would not get lose again). After this it worked perfect again :-). Of course you can also buy a spare one if you can find it.
Hope it can be of use.