IBM ThinkPad T21
The ThinkPad T21 is a 14" Pentium III-based laptop that was released in 2000. The T21 was a minor spec-bump of the T20, with both laptops sharing the same underlying architecture.
Specifications
| Spec | Details |
|---|---|
| CPU | CPU Type: Socket 495 Intel Mobile Pentium III @750, 800, or 850MHz |
| Chipset | Intel 440BX |
| RAM | Type: PC100 SDRAM, 2 slots Standard: 128MB Maximum: 512MB |
| Hard Disk | 2.5" IDE Uses proprietary adapter?: No Standard: 10, 20, or 32GB |
| Display Options | - 13.3" TFT LCD @1024x768 - 14.1" TFT LCD @1024x768 - 14.1" TFT LCD @1400x1050 |
| Graphics Chipset | S3 Savage IX8 or IX8+ VRAM: 8MB |
| Audio | Crystal CS4624 - Stereo Speakers - Microphone |
| Main Battery | Lithium Ion (6 cell) |
| CMOS Battery | Proprietary Lithium |
| Power Supply | Barrel Jack (16V) |
| Disk Drives | Ultrabay 2000 supporting the following: - 3.5" 1.44MB Floppy Drive - Various CD & DVD Drives - ZIP Drive - LS-120 Drive - 2nd HDD - 2nd Battery |
| PC Cards | 2x PCMCIA/CardBus Slots - ZoomVideo Support |
| Networking | - Modem - Ethernet (Optional) |
| Other I/O | - 1x Parallel - 1x Serial - 1x VGA Out - 1x PS/2 - 1x Dock Connector - 1x USB 1.x - 1x S-Video Out - 1x UltraPort - 1x Line In - 1x Mic In - 1x Headphone Out - Infrared |
| BIOS | IBM BIOS |
| Pointing Device | TrackPoint |
Resources
 Drivers |
 Service Manual |
Withdrawn Models PSREF |
|---|
Common Faults & Maintenance
Blink of Death
The most common fault on T21 is the "blink of death". This failure cases the laptop to fail to power on, instead just blinking a couple lights briefly. This failure is caused by the failure of one or more power regulator chips - mainly the Analog Devices ADP3421, but sometimes also the ADP3410 and the Maxim MAX1631/1632. If your T21 has this problem, you can fix it by replacing these chips. Of course, this is a difficult repair, as the chips are tiny surface mount parts (though thankfully not BGA), so not everyone will be able to perform the repair. If you can, first, try replacing only the ADP3421. This will almost always bring one back, but if the other two mentioned chips are also bad, the new ADP3421 will fail after only a short time and the issue will come back. If this happens, replace the ADP3421 again along with the other two mentioned. The laptop should then be reliable.
Page last updated (MM/DD/YYYY): 11/17/2024
Update Reason: page created
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