On Mon, Jun 5, 2023 at 1:43 PM Robert Feldman via cctalk < cctalk@classiccmp.org> wrote:
> >Message: 21 > >Date: Mon, 5 Jun 2023 04:35:28 +0100 > >From: Tony Duell <ard.p850...@gmail.com> > >Subject: [cctalk] Re: Getting floppy images to/from real floppy disks. > > > >On Sun, Jun 4, 2023 at 10:57 PM Fred Cisin via cctalk > ><cctalk@classiccmp.org> wrote: > >> > >> On Sun, 4 Jun 2023, Rick Bensene via cctalk wrote: > <> > an example of early "mobile computing". (Tongue firmly in cheek). > >> > >> The original Osborne 1 had a 12V power input! > > > >Actually it's +12.6V and +5.6V and you have to supply both voltages. > >It's one diode drop to the +5V (logic supply) and +12V (DRAM, disk > >motors, monitor supply), the -5V for the DRAM is produced on the logic > >board. > > > >I am told it was never used and that the Osborne battery pack came > >with an inverter to provide 110V AC. > > > >-tony > > It (the Osborne Powr-Pac (tm) ) has a what the manual says is a DC-DC > inverter that plugged into a Gould lead-acid battery (or the > cigarette-lighter socket in a car) at one end and the AC input of the > Osborne 1 at the other. I have read on this list that Lee denies that OCC > ever sold them, but I have one that I bought for $50 at Compumat in Chicago > on October 10, 1983 -- I still have the unit, receipt, and User > Registration card. It came with a glossy-printed grey-and-blue manual, like > other contemporary OCC products. > > If anyone wants a copy, I can email you a PDF scan of the user manual. > > Bob > Bob, I asked Lee if he could respond to this and here it is: "While I don’t recall saying that, I may well have - I know that I was involved in the engineering question of how safe it would be to use. The inverter produced 230 VDC, which it turned out could be safely fed to the 120VAC input without more than a single diode drop reverse voltage across an electrolytic filter capacitor. This was due to the power supply’s design having a voltage doubler as the first stage. It was designed by a third party who presented it to Osborne who accepted it as a branded product - exactly how they supplied it is something I don’t know (did the third party handle the production or did we?). If the question had ben posed to me as to whether it was a “battery pack” I might well have answered no because it never included batteries. Apologies for any confusion - I was always overloaded at Osborne and no one knew what a VP of Engineering’s job was until John Hanne came in in 1983. I was relabeled “R&D Fellow” in 1981 and replaced with Ed Richter." (I did get Lee's permission to post this, which was the cause of the delay in posting this as he hadn't seen my first request.) Sellam
