Duo Dock Plus

The PowerBook Duo Dock Plus is the last full-size docking station for the PowerBook Duo series that was developed by Apple Computer. Released on May 15, 1995, the Duo Dock Plus replaced the original Duo Dock and Duo Dock II, though it omitted a couple features of the latter.

Features
Like the original Duo Dock, the Duo Dock Plus features a large front-facing slot through which a PowerBook Duo notebook could be inserted. A motor would draw it into a custom 152-pin docking connector. All the ports, drives, and expansion slots of the dock would become accessible by the PowerBook Duo as a NuBus device. A 3.5-inch drive bay can accept an optional SCSI drive.

The PowerBook Duo can be ejected by pressing a button at the right. A keylock named PowerLatch allows it to be secured to prevent unauthorized ejection.

Updates
Like the Duo Dock II, the Duo Dock Plus featured a revised top cover that was 2mm taller to accommodate newer PowerBook Duo models with thicker color displays. A front door was added to keep out dust. A new AAUI-15 connector allowed the attachment of Ethernet dongles. The on-board video RAM was increased to 1MB to support up to 16-bit color on a 832 x 624 display. However, the 32KB of L2 cache and the Motorola 68882 floating-point unit from the Duo Dock II were omitted as they were not supported by newer models with 68LC040 or PowerPC processors anyway.

Supported models

 * PowerBook Duo 210 (25 MHz 68030)
 * PowerBook Duo 230 (33 MHz 68030)
 * PowerBook Duo 250 (33 MHz 68030)
 * PowerBook Duo 270c (33 MHz 68030)
 * PowerBook Duo 280 (66/33 MHz 68LC040)
 * PowerBook Duo 280c (66/33 MHz 68LC040)
 * PowerBook Duo 2300c (100 MHz PowerPC 601)

Issues
As Duo Docks age, capacitors which drive the docking mechanism are known to fail, resulting in a "Tick of Death" and requiring replacement.