Hi, thank you for contacting JustAnswer.com. My name is Russell. I will do my best to provide the right answer to your question.
The daisywheel, if one that is actually intended for use with your model of word processor,
and if properly seated and mounted firmly on the spindle, is not the problem itself, if it is printing 'gibberish', or wrong characters.
Rather the problem is in the machine's workings, specifically in either the detection of the daisywheel's position, or in the directing of the spindle to rotate to certain positions.
One way or another, your wordprocessor will, unfortunately, have to be serviced (or else, replaced) given that it has this sort of problem.
Though you can, first off, try doing a standard Reset of the machine, which might erase some things and put some settings back to factory defaults, but may set the spindle positioning problem to rights. Would you like to try a reset?
If you wish to have the wordprocessor serviced, then you either have to turn to Brother USA or Brother Canada's official repair facilities and their official capabilities... which may simply not service wordprocessors (given that they are antiques by now) ... or turn to less official facilities that might actually contain old pros who know wordprocessors inside and out and be able and willing to fix the problem yours is having (or not, if the fix requires a part that is no longer available.)
Which would you like to try? I will provide listings for either (or both), if you respond (using Reply To Expert, for instance) with your local postal code or town/city an province/region.