how can i get my royal cms 125 plus register spool fixed?

my register tape will not print out correctly. it will attempt to feed with no problem then acts like its skipping or getting stuck to where the numbers just keep printing over each other and the manual book is not detailed enough for this info. is there anyway you can give me some ideas to try so i can print out a reading? the register is an old one its a royal cash register cms 125 plus.