If Nokia BB Q10 is not abble to ring a bell and we can not use loud speaker it might be fault of ringer or it may not be attached with mother board.
It can be damage or might be its not in proper location.It can be cause of Water damages and missing components,So lets solve the problem in a few simple steps as given in above diagram.
Disassemble Blackberry Q10 and check ringer points with electronics meter.If ringer shows good value then check point on the mother board and if the have also a good value it can be cause of miss fitting.
So assembly with proper placements and tight the screw and try it if not working then replace ringer with new one.If you find some prints missing then apply jumpers as given in above diagram. There are two different color lines Red and Blue.These lines indicates the negative and positive prints of ringer in Blackberry Q10 so apply these jumper to solve ringer problem in bb q10.