Sometimes parts can be hard to find or just too expensive. Also shipping times can be a real killer, which is why it's nice we live in a no-repair society. Electronic junk is abundant and a great source of parts, as one can find all sorts of components for free, including rare and/or expensive components. A great place to visit is the local dump of course, although the dump-people seem pretty strict with their garbage.
Excellent sources of parts are;
Monitors Flyback transformer, capacitors, Ferrite, Mosfets, transistors, wire, diodes
PSUs Inductors, small components, Mosfets, diodes, PWM chip
TVs See monitor.
Microwave ovens HV cap, MOT (Transformer), HV diode
Stereo System Plenty of small components, transformer
Disposable Cameras Capacitor with charging system, first coil gun
Most large electronic equipment Heavy duty components
Harvesting parts isnít easy without some way of mass desoldering. I actually desoldered a whole monitor with just a soldering iron. It took a long time and cost me a soldering tip. The parts tend to get banged up, because youíll need to break the board up for anything with >3 pins.
Thatís where the heat gun comes in!
When using a heat gun watch the temperature on the board and components. It gets hot fast and you will likely burn the board the first few times, which smells horrible. After applying heat for some time you can just tap the board and the components will fall out. I was able to remove an entire flyback this way, along with everything else in this photo. Here is the result of 2 PSUs and a monitor, it only took a few hours.