For repairers

The Art of Trouble Shooting
Combining theory and practice, you’ll gain insight into the principles that underlie the diagnosis and repair of all machines

Battery University
A free educational website that offers hands-on battery information to engineers, educators, media, students and battery users alike.

Camera Repair Flickr Pool 
A pool on Flickr with photos of camera designs, including digital cameras.

Electronics Repair
Tips and guides by Jestine Yong to repair load of electronics products

Fixit Club
Simple instructions and tips on troubleshooting and repairing household things that break by best-selling “How Does it Work?” author Dan Ramsey.

FixYa
This site is building a crowdsourced database of help queries and personalised answers.

Future proof: Tim’s laptop service manuals
Professional, official documents published by the various laptop makers, either for their own technicians or for the use of the general public

iFixit
iFixit makes it easy to fix things with online step-by-step repair guides, troubleshooting tips, and a thriving community of repair technicians who want to help

Lowend Mac
This site proposes we use “Apple gear as long as it helps you remain productive and meets your needs, upgrading only as necessary” and helps maintain and use older kit for longer.

Powerbook Medic
An online library of repair videos mostly of Apple products.

Raising the dead: Can a regular person repair a damaged hard drive?
Very interesting article, debunking some of the myths on repairing hard drives. Also check the comments streams on this article on Slashdot

Reddit’s Computer Technicians
This space is for people who are repair professionals or aspire to be. “End users” encouraged to use /r/techsupport

Repairs Universe video library
A growing library of videos of smartphone and tablet repairs and teardowns.

sci.electronics.repair FAQ
A comprehensive historical archive of tips and guides on repairing many kinds of consumer electronics