IBM ThinkPad 755 Series
The ThinkPad 755 Series were desktop replacements sold by IBM from June 1994 through October 1996. They used late 486 and early Pentium processors.
Notable models include the 755CD which was one of the first laptops to market with an internal CD-ROM drive, and the 755CV and 755CDV, which both had a removable rear display cover that allowed the computer to be used with an overhead projector.
Specifications
Note: Different configurations of each laptop often had different release and discontinuation dates. In these cases, the earliest and latest dates will be used for each respectively. See the PSREF linked in resources for the specific dates for each configuration.
| Spec | ThinkPad 755CS | ThinkPad 755C | ThinkPad 755CSE | ThinkPad 760CE | ThinkPad 755CD | ThinkPad 755CX | ThinkPad 755CV | ThinkPad 755CDV |
|---|---|---|---|---|---|---|---|---|
| Release Date | June 1994 | November 1994 | October 1994 | October 1994 (Pentium model introduced Sept. 95) | May 1995 | June 1995 | ||
| Discontinuation Date | May 1995 | December 1995 | Unknown | June 1996 | June 1996 | Jun. 1996 (486), Oct. 1996 (Pentium) | ||
| CPU Options | - Intel 486DX2 @50MHz - Intel 486DX4 @75MHz |
Intel 486DX4 @100MHz | - Intel 486DX4 @100MHz - Intel Pentium @75MHz |
Intel Pentium @75MHz | - Intel 486DX4 @100MHz - Intel Pentium @75MHz |
|||
| RAM (Standard) | 4MB | 8MB | ||||||
| RAM (Maximum) | 20MB w/ IC DRAM or 36MB w/ 72pin memory module adapter | 20MB w/ IC DRAM or 40MB w/ 72pin memory module adapter | 40MB w/ IC DRAM or 72pin memory module adapter | |||||
| RAM Type | IC DRAM or 72pin | |||||||
| HDD Standard Size | 170, 340, or 540MB | 340, 540, or 810MB | 540MB, 810MB, or 1.2GB | |||||
| HDD Type | IDE 2.5" | |||||||
| Uses Proprietary HDD Adapter? | I believe so for all of them. | |||||||
| Display Options | 9.5" Passive Matrix Color | 10.4" Active Matrix Color | 10.4" Passive Matrix Color | 10.4" Active Matrix Color | 10.4" Active Matrix Color | |||
| Display Resolution | 640x480 | 640x480 (model without sound) or 800x600 (model w/ sound) | 640x480 | |||||
| Display Color Depth | 256 Colors | 65,536 Colors | ||||||
| GPU | WD90C24A or WD90C24A2 | WD90C24A2 | WD90C24A (Rev C) | WD90C24A2 | ||||
| VRAM | 1MB | |||||||
| Sound | Crystal CS4248 | IBM Mwave MDSP2780 | Optional IBM Mwave MDSP2780 | IBM Mwave MDSP2780 | ||||
| Battery | NiMH | - NiMH - Lithium Ion (Pentium models only) |
NiMH or Lithium Ion | |||||
| CMOS Battery | Unknown | |||||||
| Power Supply | IBM 4-pin proprietary | |||||||
| PC Cards | PCMCIA 2x Type I/II or 1x Type III | |||||||
| Media Drives | Ultrabay (Original) (No CD-ROM support) | Ultrabay Thick (CD-ROM support) | Ultrabay (Original) (No CD-ROM support) | Ultrabay Thick (CD-ROM support) | ||||
| Networking | None | Modem | Optional Modem (on model w/ sound) | Modem | ||||
| I/O (Other) | - 1x VGA Out - 1x Parallel - 1x Serial - 1x Dock Connector - 1x PS/2 - 1x Line In - 1x Line Out |
- 1x VGA Out - 1x Parallel - 1x Serial - 1x Dock Connector - 1x PS/2 - 1x Line In - 1x Line Out - 2x Infrared |
- 1x VGA Out - 1x Parallel - 1x Serial - 1x Dock Connector - 1x PS/2 - 1x Line In - 1x Line Out - 2x Infrared - 1x Proprietary Multimedia Connector* |
- 1x VGA Out - 1x Parallel - 1x Serial - 1x Dock Connector - 1x PS/2 - 1x Line In (sound models only) - 1x Line Out (sound models only) - 2x Infrared |
- 1x VGA Out - 1x Parallel - 1x Serial - 1x Dock Connector - 1x PS/2 - 1x Line In - 1x Line Out - 2x Infrared |
- 1x VGA Out - 1x Parallel - 1x Serial - 1x Dock Connector - 1x PS/2 - 1x Line In - 1x Line Out - 2x Infrared - 1x Proprietary Multimedia Connector* |
||
| BIOS | IBM BIOS with Easy Setup | |||||||
| Pointing Device | TrackPoint | |||||||
| Special Features | None | Rear screen panel is removable to allow use with an overhead projector | ||||||
*I believe this includes a MIDI/Game Port, and Composite in/out.
Resources
 Service Manual |
Withdrawn Models PSREF |
|---|
Common Faults & Maintenance
The ThinkPad 755s are generally well-built laptops. Build quality is good, and hinge failures are rare. Still, a couple of things MUST be addressed to keep them working.
Reserve Battery Leaks
I'm not positive on this, but I believe the 755 series laptops have a Lithium CMOS battery somewhere inside. What I am sure of though, is that they ALSO have a VARTA NiMH battery, located under the Ultrabay. These batteries nearly always leak with age and MUST be removed or the laptop will eventually stop working.
Sticky Rubber
The entire case of the 755 ThinkPads is coated in a soft touch rubber coating. This coating nearly always turns sticky with age and must be removed from the laptop.
Capacitor Failure
The older 750 Series models are fully in the "need to recap" zone and these aren't far behind, if they're not already there as well. I believe the display has several electrolytic caps that may need replacing.
Gallery
If you own a 755 Series laptop and would like to send in photos I could use, email me: macdatnet@gmail.com
Page last updated (MM/DD/YYYY): 11/15/2024
Update Reason: pages consolidated
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