PowerBook Duo 250
The PowerBook Duo 250 is a 68030-based subnotebook that was released in 1993. It shared the same specifications as the Duo 230, but featured a beautiful Active Matrix grayscale LCD instead of the more standard passive panel found in the other Duos. Along with all other Duo models, the 250 supports a variety of docking station solutions to add functionality - everything from Micro Docks which added single ports, to the full-size DuoDock, which turned the 250 into a full desktop computer setup.
Specifications
| Spec | Details |
|---|---|
| Release Date | October 1993 |
| Discontinuation Date | May 1994 |
| Processor | Motorola 68030 @33MHz |
| Bus Speed | 33MHz |
| RAM | PowerBook Duo Proprietary Standard: 4 or 12MB Maximum: 28MB |
| Hard Disk | 2.5" 40-pin SCSI Standard: 200MB |
| Display | 9.1" Active Matrix Grayscale (16 shades) LCD @640x400 |
| GPU | Chips & Technologies 65210 VRAM: Unknown |
| Main Battery | NiMH (Type II) |
| PRAM Battery | Proprietary Lithium |
| Power Supply | RCA-style Jack - Apple M2693 AC Adapter |
| Media Drives | None, external floppy drive supported with docking stations |
| PC Cards | None |
| Networking | Internal Modem (Optional) |
| Other I/O | - 1x Serial - 1x Duo Dock Connector |
| Pointing Device | Trackball |
| Minimum Mac OS | System Software 7.1 |
| Maximum Mac OS | Mac OS 7.6.1 |
Upgrades
SSD Upgrade
See our page on SCSI SSDs for more info.
Resources
 User Manual |
 Service Manual |
Capacitor Reference |
|---|
Common Faults & Maintenance
Capacitor Failure
The Duo motherboard has several surface-mount electrolytic capacitors on it that fail and leak corrosive fluid due to their age. These capacitors MUST be replaced, as running one with original leaky caps risks sending 24V (charger voltage) straight into all the 5V circuitry in the laptop.
If you're using the original Duo AC adapter, it also needs attention - it has a RIFA filter capacitor inside that is prone to exploding, which releases nasty smelling smoke into your room.
LCD Tunnel Vision
Like other laptops with Hosiden TFT mono/grayscale LCDs, the Duo 250's panel nearly always develops the tunnel vision defect.
Brittle Plastic
The Duo's plastics have gotten brittle over time, which leads to the weak display hinge mounts crumbling and failing. The proper fix for this is to replace them with 3D-printed replacements, but alas, there isn't yet an STL template for the grayscale model Duos. If your Duo has failed hinge mounts, you can either reinforce them with epoxy, or design a 3D printed replacement yourself.
Keyboard Failure
The Duo keyboards, besides being terrible to type on, now develop bad keys very often. This is caused by the membrane contacts oxidizing with time. To fix this, you can paint over the corroded traces with a conductive pen to increase the electrical contact. While you have the keyboard apart, you may also wish to use a plastic-safe lubricant to try to relieve some of the stiffness of the keys.
Other Issues
As with any laptop this old, you're pretty likely to run into dead or missing hard drives. The Duo's display can also develop vinegar syndrome.
The Duo's main battery is prone to leaking. The PRAM battery is not, but the Duos can sometimes act up when its dead. If only the power button on the rear of the laptop works, this is a likely cause.
Page last updated (MM/DD/YYYY): 03/11/2025
Update Reason: page rewritten
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