🇺🇸 Osborne 1: Part 2 (Powering On & Dismantling) [TCE #0503]
33So I RTFM: [1] switched the PSU from 120VAC to 240VAC, and [2] plugged in the EXMON dongle to the "EXT MON" port to get video output working on the built-in CRT (and also captured).
None of the three disks I have will boot - I suspect that the CP/M system files aren't included on them so I need an actual CP/M 2.2 boot disk for the OCC1. You can switch to booting from Drive B: by holding [SHIFT]["].
I pulled the machine apart - wasn't too difficult, although you do need some space. It's definitely a lot easier than the IBM Portable PC to pull apart!
The 5¼" floppy drives are Siemens model "FDD 100-5" and use belts.
It came as no surprise that the power supply had a few RIFA capacitors used as class X safety filters ... and one had blown up. So I'll replace those whilst I have it apart: the main 0.1µF (100nF) that had blown and two smaller 0.01µF (10nF) that were starting to look a little iffy.
I know it's possible to buy a set of disks, but I should also be able to make my own images with the tools I have. I might try to get it running off a Gotek/Flash Floppy in the interim.
For that, this small PCB looks useful:
https://www.pcbway.com/project/sharep...
... or ...
https://github.com/WayneVisser/Osborn...
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From Part 1:
Let's have a quick look at this Osborne OCC1 computer from 1981, a luggable Z80-based machine with 64KBytes of RAM, dual 5¼" floppy drives and a built-in 5" monochrome screen.
It only runs on mains power - the power supply is simple to switch between 120VAC and 240VAC. It has an interesting array of ports on the front - full featured really: an external battery (DE9 socket), video output (edge connector), IEEE488 port, RS232 serial (DB25) and a modem port ... with modem.
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