ThinkPad 755

IBM ThinkPad 755 series

Company type	Product line
Industry	Computer hardware
Predecessor	ThinkPad 750
Founded	1994
Successor	ThinkPad 760 series
Products	Notebook-sized laptops

The ThinkPad 755 series represents a line of premium notebook-sized laptops introduced by IBM between 1994 and 1996. These models were equipped with either Intel's i486 or the original Pentium processors, with clock speeds ranging from 50 to 100 MHz. Notably, the ThinkPad 755CD, released in October 1994, was pioneering as the first notebook to incorporate an internal full-sized CD-ROM drive. During 1994, this series dominated laptop sales, surpassing competitors such as Apple Computer and Compaq. IBM followed up this series with the ThinkPad 760 lineup in January 1996.

ThinkPad 755C and 755Cs

IBM unveiled the ThinkPad 755 family in April 1994, with availability commencing on May 17. This series succeeded the ThinkPad 750 as IBM’s flagship notebook. The initial releases included the ThinkPad 755C and 755Cs models. Both were powered by the clock-doubled variant of the i486 processor, the Intel DX2 running at 50 MHz, with an option to upgrade to the triple-clocked Intel DX4 at 75 MHz. The 755C featured a 10.4-inch color active-matrix TFT LCD, whereas the 755Cs was fitted with a smaller, 9.5-inch color passive-matrix STN LCD. Storage configurations included either a 340-MB or a 540-MB hard disk drive, complemented by a 3.5-inch floppy disk drive capable of handling 2.88 MB.

ThinkPad 755CE, 755CSE, 755CD

In October of the same year, IBM expanded the lineup with the introduction of the ThinkPad 755CE, 755CSE, and 755CD models. These all utilized the i486DX4 processor operating at 100 MHz via a daughterboard that supported aftermarket upgrades. The standout feature of the 755CD was its status as the first notebook to integrate an internal full-sized (120 mm) CD-ROM drive—a double-speed tray-loading unit housed within the ThinkPad UltraBay located beneath the keyboard. This addition increased the device’s thickness by approximately 7.2 mm. For users of the slimmer 755CE and 755CSE models, which lacked built-in CD-ROM bays, IBM offered the CD-ROM drive separately for use in an external UltraBay enclosure.

These iterations replaced the earlier Crystal Semiconductor sound chip with IBM's proprietary Mwave digital signal processor, which combined functionalities such as a 14.4-Kbps modem/fax, speakerphone capabilities, and an answering machine. The TrackPoint device was refined with a more textured grip and firmer click buttons to enhance user interaction. Display choices included a 10.4-inch active-matrix TFT LCD featuring a "Black Matrix" polarizer on both the 755CE and 755CD models, while the 755CSE retained a passive matrix STN LCD panel. Hard drive options ranged from 340 MB up to 810 MB.

By September 1995, IBM offered an optional Pentium processor daughtercard clocked at 75 MHz for these models, providing improved computing power despite its lower frequency compared to the i486DX4.

ThinkPad 755CDV, 755CV, 755CX

In June 1995, IBM refreshed the ThinkPad 755 series with three new variants: the 755CDV, 755CV, and 755CX. The first two maintained the use of a 100-MHz i486DX4 processor, while the latter marked IBM’s debut of a Pentium-based laptop running at 75 MHz.

The designs of the 755CDV and 755CV were distinctive due to a detachable tray that housed their backlight for the respective 10.4-inch active-matrix TFT LCDs; removing this tray rendered the screen transparent. Additionally, these laptops could be folded flat by rotating their displays through a full 180 degrees—allowing them to be employed with standard overhead projectors for projecting graphical content. This approach served as an economical alternative to dedicated VGA projectors that were still costly and cumbersome during that period. This convertible concept echoed earlier innovations such as Revered Technology Inc.'s Power Cruiser.

Among these models, only the ThinkPad 755CDV came equipped with an internal UltraBay CD-ROM drive preinstalled; neither the 755CV nor the newly introduced Pentium-based 755CX included this feature internally. All three continued to utilize IBM’s Mwave DSP technology as seen in prior versions of the series. By August of that year, IBM upgraded the display resolution on the ThinkPad 755CX from VGA (640×480) to Super VGA (800×600). Subsequently in September, an optional Pentium processor daughtercard running at 75 MHz became available for both the 755CDV and the 755CV models, broadening performance choices for business professionals.

External links

• Official site (755CE/CSE/C/CS) (archived)
• Official site (755CDV/CV/CD) (archived)
• Official site (755CX) (archived)