The PowerBook Duo was for many years one of Apples smallest laptop computers. The initial two Duo's were called the 210 and 230 and had 68030 processors running at 25 MHz and 33 MHz respectively. They both use a 4-bit passive-matrix screen which displays black and white images. A black and white screen Duo 250 was also produced.
These pages are going to discuss the later colour versions of the Duo which were the 270c, 280c and 2300c. The 270c used a 68030 cpu running at 33 MHz while the 280c used a 68LC040 processor running at 33 MHz and finally the 2300c which shipped with a PPC 100 MHz cpu.
All PowerBook Duo's are similarly configured on the rear panel. From left to right, an optional modem, reset button, Duo Dock connector, power plug and serial connector which can be used for a modem, printer, appletalk or other serial device.
The keyboard can now be flipped over. If you need to get at the hard drive then you must now unclip the two ribbon cables
Once the keyboard is removed, remove the battery as well. Note the memory module which is on the far right below the modem module. Also note that this 270c has the 2300c motherboard upgrade.
One trick to taking apart a Duo is to remove these small plastic clips. They slide out.
Once the cover slides are removed you can take off the top plate, it is clipped in place on the front right corner so you need to push the cover forward slightly to unhook the tabs then you can pull the plate up and off.
Once the top plate is removed you have full access to the rest of the internal components. At the bottom right is the hard drive which in the 2300c upgrade can be either SCSI or ATA. In the middle is the trackball and below it is the pram battery.
On the 2300c the metal shield is held on with 1 screw and can be folded back to expose the hard drive.
The hard drive can now be removed by removing the two screws. Unplug the ribbon cable at the motherboard once the hard drive caddy is unscrewed. Note that this caddy is designed for older hard drives. All of my newer ATA drives have screw holes in different places.
The 2300c conversion has no problems running OS 9.1.
The Duo 280c was the fastest of the 040 powered Duo's and was also the last Duo to feature a trackball instead of a trackpad.
The only difference between the 270/280/2300 bases are the labels.
The layout of the 280c motherboard is not a lot different from the 2300c. Note the same location of the memory and modem cards. The CPU is under the metal heat sink at the top middle of the photo.
The last of the Duo's the 2300c. The most obvious difference was the trackpad which replaced the trackball.
Another difference that isn't so obvious is that the 2300c has a slightly larger LCD screen.
My original 2300c on the left and my upgraded 270c on the right. Note that the 2300c motherboard will support either the trackpad which is built into the lower top case or the trackball which is mounted to the bottom shell.
What is interesting is that the 2300c still only supports 256 colours for the full screen.
When you bump up to thousands of colours you loose a substantial portion of your screen. I have no idea why Apple did this.
Just for comparison purposes here is a photo of my PowerBook 2400c. It is almost the exactly same size as a Duo though actually a bit smaller in terms of width and depth while being slightly thicker but with a much larger display. Still the Duo was an amazing small light laptop for it's time and even today in 2008 still fairly useable if running OS 9.
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