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IBM PC Convertible 5140

Brand: IBM.
Model: PC Convertible 5140.
Origin: USA.
Introduction: 1986.
Type: Portable LCD computer based on an Intel 80c88 chip at 4.77 MHz, 256 Kb of RAM (expandable to 640 Kb), two 720 Kb 3.5" floppy disc drives, XT style keyboard and an expansion port for accesories (external monitor, printer, modem, etc). It is IBM PC compatible and runs IBM PC DOS 3.2 operating system.
Description: This is the first true portable computer made by IBM. It is operated with AC power and with a battery pack with very low consumption, also has a carry handle. This machine is also the first in other areas: It is the first IBM computer that uses the new 3.5" floppy disk , this format was the standard since 1985 until arrival of modern pendrives!. IBM used 3.5" floppy disk units in all PS/1 ans PS/2 personal computer series. Also, this is the first computer in use surface mount technology, a technique which permitted more electronic components to be mounted onto circuit boards.

The external case was designed in Germany and has a particular behavior: When you open the display the two floppy disc drives moves up for an easy access. When closed, this drives are aligned with the keyboard, this allows to reduce the height of the closed machine.
Display: A 10" monochrome Liquid Cristal Display with a contrast sliding switch. It has an alphanumeric resolution of 80x25 characters and CGA graphic resolution of 320x200 pixels. With external monitor the computer has EGA resolution with 640x200 pixels. The IBM PC Convertible 5140 model 2 (actually the first model!) has a reflective supertwist LCD with no backlight, so the visibility is quite poor, but the benefit is a very long operating time with battery, around 10 hours!.

The LCD display can be removed and you can connect an external monitor, so this machine can be used as a true desktop computer, hence the name "Convertible". This concept is similar to the Hewlett-Packard Portable Vectra CS.
Keyboard: 78-key full-travel XT style keyboard without separate numeric pad. Includes a F key to allow second functions usually seen on full XT keyboard layout. Also there is a separate On/Off/Suspend switch.
Main chips: Intel 80c88 (a CMOS low-power version of the 8088) at 4.77 MHz.
Remarks: The first laptop from IBM, previous to the famous Thinkpad series. Also this machine was the base of the design of the PS/2 series. The style of the keyboard and floppy disc units is easily distinguishable in PS/2 models like models 20 or 80.
Size: 12 x 15.94 x 2.76 in, 30.5 x 40.5 x 7 cm. Weight: 12 lbs, 5.5 kg.
Condition: (7/10) Good, full working but battery is dead and I removed it.
My example was built in march 1986, so I think it is from the very first production batch!
Accesories: External AC power adapter. Attachable expansion port for serial and parallel ports.
Download: IBM PC Convertible Promotional brochure in PDF format, click here.
IBM PC Convertible Features in PDF format, click here.
IBM 5140 Startup diskette version 1.03 (84X0107), click here.
IBM 5140 Diagnostics Update diskette version 1.03 (84X0111), click here.
All material is from
Additional readings: The IBM PC Convertible 5140, from, click here.
The IBM PC Convertible 5140, from, click here.
The IBM PC Convertible 5140, from, click here.
A technical description of the IBM PC Convertible 5140 from, click here.


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