Cracking Open the IBM PC Jr.

Empty expansion slots

The red arrows mark where the floppy controller, RAM expansion, and power controller were connected to the motherboard. The IR sensor is still installed, but will be removed before long.


Mark W. Kaelin has been writing and editing stories about the IT industry, gadgets, finance, accounting, and tech-life for more than 25 years. Most recently, he has been a regular contributor to BreakingModern.com, aNewDomain.net, and TechRepublic.