Best fix......crack open case, hand Drill thru or pull out old wire from the "strain relief tail" ....clean and pull thru un-frayed new wire, (coat it with
liquid electrical tape from Jaycar)
Ensure you have enough wire pulled thru to resolder, use a cable zip tie to stop the cable pulling again. Let it dry reassemble.
The liquid electrical tape and zip tie will stop it moving again. An alternative is do the above but use glue lined heat shrink....Its damn good.