I had to recap a power supply in an Imagewriter 2 back in the late 90s, so i know for sure that the time is getting near. the imagewriter i worked on was stored in high heat conditions so thats probably the reason why.

I realize these arnt stylewriters, but same concept applies. HOWEVER.... the stylewriter that has no servo action could be as simple as a popped supply fuse going to the driver IC. Reason could be unknown.