IBM PC Convertible 5140

The PC Convertible was IBM’s first laptop-style computer. It used a low-power CMOS 8088, a folding LCD and 3.5-inch floppy drives in a battery-operated clamshell design.

Its modular rear expansion system and modern disk format were forward-looking, although weight, price and a display without backlighting limited its appeal.

Notable Features

• It was IBM’s first computer to use 3.5-inch floppy disks.
• Clip-on modules expanded the rear of the machine with communications and display interfaces.

Historical Significance

• Its modular rear expansion system and modern disk format were forward-looking, although weight, price and a display without backlighting limited its appeal.

Collector’s Notes

• Original IBM documentation, matching display and keyboard, and an unmodified configuration add historical context.
• Memory, storage, displays and expansion hardware should be documented because configurations often changed during a system’s working life.

Specifications

Technical Information
Name	IBM PC Convertible 5140
Manufacturer	IBM
Launched	Tuesday, April 1, 1986
Discontinued	1989
Country	United States
CPU	Intel 80C88 at 4.77 MHz
Units Sold
Form Factor	Battery-powered clamshell portable
Power	Rechargeable battery or AC adapter
Networking	Optional modem
Operating System	IBM PC DOS
Expansion / I/O	Rear expansion connector for printer, serial, display and modem modules
Keyboard	Integrated laptop keyboard
Storage	One or two 720KB 3.5-inch floppy drives
Sound	Programmable speaker
Colours	Monochrome
Graphics	CGA-compatible monochrome graphics
Display	Built-in 640 x 200 monochrome LCD
ROM	IBM Convertible BIOS
RAM	256KB standard; expandable to 640KB
CPU Speed	4.77 MHz