IBM Personal System/2 Laptop 40 SX (PS/2 L40SX) Notes


IBM PS/2 L40 SXThe L40 SX was announced on March 26, 1991. Here are some highlights from the announcement letter:

Standard features:
The machine was targeted at mobile professionals with an initial price of $5995 for the base model without options, which would be over $11,300 in 2020 equivalent dollars. To put things in perspective, a base model 1991 Nissan Sentra had a manufacturer's suggested retail price of $8290. The 2MB memory upgrade started at $899, while the 8MB memory upgrade was an eye-popping $3595.

Prices dropped several times during the life of the machine:
On July 9th, 1992 IBM withdrew the PS/2 Model L40 SX from marketing, making it available for sale for a little over 15 months.

Technical Notes

Here are some things to keep in mind with these machines:


There are three batteries on these machines:

Hard Drives

IBM originally sold the machine with a 60MB Conor hard drive. Surprisingly, the hard drive is a standard 2.5" IDE mobile drive. If you find a machine with the original hard drive you can assume it is dead; I've only seen one surviving original hard drive.

While the hard drive is a standard IDE hard drive, the ribbon cable that connects the drive to the motherboard is not standard and it is very fragile. Be careful working with it.

If you have to replace the hard drive don't use a mechanical hard drive. Use a Disk-On-Module or an industrial Compact Flash card. See "Upgrading an IBM L40 SX to an SSD" for the procedure.


The standard machine came with 2MB of memory on the motherboard. Two memory slots allow for expansion to a maximum of 18MB. The memory is not standard so you have to find the exact part numbers. The memory upgrades were expensive options so finding a machine with a lot additional memory is unusual.

Communications Cartridge I

IBM PS/2 Communications Cartridge IThe Communications Cartridge I (model 3541-001, 06G8050) is an option that allows one to use the L40 SX to connect to midrange or mainframe computers. The device itself is a self-powered bus expansion that holds one short 8-bit ISA card and connects to the L40 SX using a thick cable. Originally intended for use with Token Ring adapters, 3270 emulation cards or 5250 emulation cards, it also can work with other ISA cards such as Ethernet or SCSI cards.

The announcement letter for the L40 SX indicated that an option like this would be available. It was finally announced on October 17th, 1991. These were originally priced at $595 so you won't find too many of them in the wild.

Cards known to work:

Communications Cartridge circuit board, top Communications Cartridge circuit board, bottom IBM Communications Cartridge Cable
Internal circuit board, top view
Internal circuit board, bottom view
Bus connector cable


Here are some resources that you will find useful for your L40 SX.

(Special thanks to John Roth who provided the paper marketing brochure, the keyboard templates, the L40 SX Presentation guide, and the Communications Cartridge instructions.)

Keyboard template:

IBM provided blank templates that you could write on to remind yourself of the special key combinations of programs you were using. (Right click to save the full sized image.)

IBM L40 SX Keyboard Template

IBM announcement letters:
Reference Diskettes:
These are a standard 1.44MB diskette images. You can create a 3.5" diskette from these images using dd (Linux), WinImage (Windows), or DskImage (DOS).

External Links:

Created August 16th, 2020, Last updated November 26th, 2020
(C)opyright Michael B. Brutman, mbbrutman at