The Duo Dock and Duo Dock II were designed to allow Apple's PowerBook Duo to have a docking station which provided access to a built in floppy drive, second internal hard drive, larger monitor and 2 nubus slots.
Pictured above is my Duo Dock II with PowerBook 270c loaded in the slot. The Dock has a standard for the period DB-15 monitor plug on the rear however using a DB-15 to VGA cable I am able to drive my LG LCD monitor.
Using the built in video of the dock with a vram upgrade I am able to drive my 19" monitor at a maximum resolution of 832 x 624 in thousands of colours.
To remove the top of your Dock just press in on the front corners of the lid and lift it up and back.
The top of the motherboard has a slot for a single vram card. This is the same vram that can be found in older Macs such as the LC and LCII. There is also an FPU socket in the top right corner of the board which I have populated with an FPU chip. Note the multicoloured cable hiding under the grey scsi ribbon cable, this must be unplugged before you can access the components inside the Dock.
Two slotted screws hold the Dock together, they are sunked into the bottom plate one has a screwdriver sticking out of the hole in the middle of the photo. A second screw must be loosened in the upper hole on the right side of the photo. Once these are loosened you can lift up and pull off the top portion with motherboard.
Make sure you unplug the power cable!
Under the motherboard you will find an HD floppy drive which is common to all desktop Macs of the period as well as an internal scsi hard drive. Note that the scsi cable in the photo is not an original Apple part and that there are no other mounting points for internal scsi devices.
The Dock has two full length nubus slots shown on the left side of the above photo.
Even though the Dock has a standard mini phone jack it does not support stereo audio output.
Even though I have a Dock II lid on my Dock I believe this is an original Dock since it does not have the AAUI port just the cover. Starting at the top left we have a standard telephone jack, microphone, and speaker plugs, PowerBook scsi port, cap for the AAUI port found on Dock II's, printer port, modem port, DB-15 monitor port, ADP port, reset button. On the lower portion is a power pass through, power plug, and the two nubus slots.
The original Duo Dock has a slightly shorter opening than the Dock II and therefore the newer colour Duos won't fit without a slight modification that propped the lid up slightly at the front. The Dock II addressed the issue with a slightly taller opening. I read online that the original Dock with FPU installed will not work with the 280c or 2300c however mine does so I'm not sure what to suggest here. If you have problems check and see if you have the FPU installed and if so you might have to remove it.
For it's time the Duo was a very small laptop only the newer PowerBook 2400c was as small and with the help of the Dock the Duo was able to function in much the same way as a desktop computer. The only downside was that all of the connectivity, floppy and extra hard drive resided in the Dock.
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