iFixit a web site and 'brand', is quite well known for its ever expanding database of DIY repair guides for household and tech items - and it's now on Windows Phone too. There's an undoubted USA bias to the products covered, plus the database is patchier than you might think. However, if you strike lucky then the vital steps you might need help with may just be here after all. iFixit's app is free too, so why not grab it anyway and maybe it'll have your 'widget A' covered by the time it goes wrong?
uggy, won't let me select most items, many items off the bottom of panes 8-(
iFixit — the free repair manual! Thousands of step-by-step guides, gorgeous images and engaging videos that make it easy to repair your stuff. Repair manuals show you how to fix:
MacBook Pro Repair
PowerBook & iBook Repair
PC Laptop Repair
Dozens of digital camera repair manuals
Hundreds of cell phone repair manuals
Harley Davidson Repair
Honda Accord Repair
More manuals added every week
Categories like 'Phone Repair' sound all inclusive, but it should again be noted that the actual models included are somewhat limited. The iFixit team do encourage users to get involved, mind you, so maybe you can get involved in supplying repair photos and instructions for something you've worked on?
Here's iFixit 1.1 in action (v1.0 had some horrible UI bugs):
The glossy homepage and category selection; (right) you can also search for products or categories directly.
Having found the right product, just swipe right to go from step to step, each of which is illustrated, as shown here.
iFixit's famous device 'teardowns' are also included, for interest's sake. Here's their write-up of the old Nokia N95 classic from 2007...
It's not just tech products, either - there are plenty of car repair guides too.