
History
This keyboard originally came with IBM Personal Computer AT (PC/AT). This computer was released in 1984, and IBM has produced over 100,000 units before discontinuing them in 1987. Some sources say that the AT stands for Advanced Technology.

This model was a successor to the very famous and now weird XT layout. The IBM PS/2 (Personal System/2) was the successor to the IBM PC/AT, and with it came the venerable model M keyboard. The model M keyboard introduced the very layout that is being used worldwide even today.
Acquisition & Restoration
I have acquired this keyboard from eBay for a fair price. It was super dirty and was full of gunk. The barrel plate has rusty, and there were a bunch of dead spiders inside. The keycaps were quite filthy too.

The Foam was rotten and kept falling out the whole time; However, the back rainbow plate was pristine, and there weren’t any rust spots on it.

I removed the caps and barrels and washed them in warm soapy water. Then scrubbed the barrel plate but couldn’t repaint it because I ran out of spray paints by then. Replaced the rotten foam with a hand-made 2mm one, and reassembled everything.

It was an absolute joy to use the keyboard on modern machines. It uses AT protocol, So using a passive AT to PS/2 converter would do the trick. Since I don’t own a computer with a native PS/2 port, I daisy-chained an active PS/2 to USB (A) converter and then another Type A to Type C adapter to connect my Macbook Pro.