Greetings. I'm starting up a small computer repair shop and I noticed that my inventory has a ton of old fans. I'm looking to make a device that I can plug computer fans into to test them. Yes, I know I can use a 9-volt and a couple wires, but it's been years since I actually made something and would like to refresh the data instilled in me by my father before he died. I'd like the box to be able do this: 1) Either plug directly into the wall or use an AC power adapter (most likely wall). 2) Have connectors to plug in various fan types (3-pin bearing in mind that some 3-pins have wires in different spots, 2-pin, etc.) 3a) Have a selector switch for voltages from 5v-12v or any other voltages I'd need. 3b) Variable potentiometer with meter (analog or digital (which would be cool)) to display output voltage (speed control). 4) In-line fuse for safety. 5) On/Off switch. If someone would be willing to draw up a schematic for this, I'd appreciate it. I'm not too good at drawing them, but I can understand them pretty well (I can tell the difference between a resistor symbol and a capacitor symbol) and am fairly good at assembly. Thank you in advance. Drew Vedbraaten First Aid Computing "We breathe new life into old computers!"