Here’s a website devoted to resources to fix IBM Selectric typewriters.
I’ve got a digital version on RL Summers’ Troubleshooting the Selectric up now. Also added is the IBM Service Manual S241-5615-3.
Reach me at idontlikespam48 (at) gmail.com with constructive criticism. If you have better pictures than me, send them over. If I made a mistake in one of my pictures, let me know. If there’s something I should add to the site, tell me about it!
Here’s a link to the manuals: