The best PDF is the one that matches your machine's serial number. Keep it on a tablet in the control room and a backup on your company server.
Below is a draft for a professional blog post tailored for engineering and construction audiences.
Includes templates for and standardized record-keeping.
This is the "first page" most users want. It should list:
“My grandfather was a lead tester at the Birmingham works. He kept a personal copy of the TR6 service manual—the one with the handwritten field notes. I’ve digitized it. It’s 400 pages of mechanical poetry. Check the attachment.”