Dragon 32: Part 1

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The Clueless Engineer

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Published on February 13, 2023 5:50:28 PM ● Video Link: https://www.youtube.com/watch?v=72LvEHGdzIQ

Duration: 36:34

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The Dragon 32, from Welsh company Dragon Data, is a close cousin of the Tandy TRS-80 Colour Computer (CoCo1) as they were both created from the same 6809 reference design.

04;45 ... removed top case
07:45 ... removed power supply/video output board
08:38 ... cleaning done
12:35 ... electrolytics replaced
14:40 ... testing the power supply board
19:00 ... making a monitor cable (composite/audio)
32:40 ... finally testing the machine

The supplied power supply brick outputs 8.5VAC (1.5A) and 28VAC (250mA). The internal power supply board then generates a regulated +5VDC (LM309), +12VDC (7812) and -5VDC (7905).

I have two machines but only one power supply brick ... if I replace those linear regulators with modern switching versions then I should be able to supply just a single 15VAC input ... ?

I could only replace two of the power supply board electrolytic capacitors (4700µF) as I didn't have axial replacements for the others: 470µF/35V and 220µF/35V.

Next up - finding some Dragon software and loading via the CoCoSDC interface. I also need to give the keyboard a clean, as well as a proper clean of the case. Oh, and also check out the 2nd machine.

https://worldofdragon.org/

Part 2:
https://youtu.be/1_USfg3G3Tw

Part 3:
https://youtu.be/o0xAoE05nHc