The IBM Model M keyboard is notorious for its loud clacking keys, solid construction and tactile feedback which has made it a favorite of many serious keyboardists despite the fact that its design is now decades old. Unicomp still manufactures Model M keyboards, and offers some modern updates such as Windows keys and a USB interface. This is a great option to have, but like so many others I still rely on older versions of the Model M that have a PS/2 interface, which is no longer included on mainstream computers. So an adapter is necessary, and there’s many out there to choose from. But as most Model M enthusiasts know, not all adapters work with the Model M.
The problem is that Model M keyboards consume significantly more power than modern keyboards, and not all adapters (or motherboards, for that matter) can provide enough current on the PS/2 port to power a Model M. I’ve known this for a long time, but never knew exactly how much current a Model M draws vs. a modern keyboard. I decided to find out.