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File:Internal HDB-DOS Eprom Upgrade PCB installed into a Korean Coco 2B.jpg

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The Internal HDB-DOS Eprom Upgrade PCB is shown installed in a Korean Coco 2B in its first successful test configuration. Notice the red wire in the 14 pin socket. Its purpose is to pass the chip select signal on to the 27128 eprom. The blue wire connects pin 27 (programming mode enable, an active low pin) of the eprom is connected to pin 28 of the Eprom which provides +5V to keep the eprom out of programming mode. The orange wire is not connected to anything since HDB-DOS is not being tested yet.

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current01:26, 24 October 2013Thumbnail for version as of 01:26, 24 October 20131,536 × 2,048 (542 KB)Computerdoc (talk | contribs)The Internal HDB-DOS Eprom Upgrade PCB is shown installed in a Korean Coco 2B in its first successful test configuration. Notice the red wire in the 14 pin socket. Its purpose is to pass the chip select signal on to the 27128 eprom. The blue wire co...

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