Osborne-1 with prototype-based motherboard

[Brad H]

There are definitely some differences.

For example, the ROM BIOS on mine is contained on two 2716s instead of a
single 2732 as in the later boards.  There's  a few jumper wires on the
board too.   I imagine it's largely the same, although if it were completely
I'm not sure why they'd do a full redesign and not, like you said, use some
of that extra space for more RAM or something.  Lee himself didn't really
know.. all he said was that that space, in the prototypes, was occupied by
linear voltage regulators that were changed/designed out after.

Maybe what I'll do is make a complete list of the ICs and see how it lines
up with a later production board.  And then compare other components.

-----Original Message-----
From: cctalk [mailto:cctalk-bounces at classiccmp.org] On Behalf Of Jules
Richardson via cctalk
Sent: Saturday, December 29, 2018 4:21 PM
To: cctalk at classiccmp.org
Subject: Re: Osborne-1 with prototype-based motherboard

On 12/29/18 2:53 PM, Brad H via cctalk wrote:
> Am just posting this as I am hoping someone out there knows someone 
> who was involved with Osborne back in the day to find out more this 
> Osborne 1 motherboard I found in a low serial O1 I picked up for $100.

Is it just the board layout that's different, or does it appear to be a
completely different animal, schematic-wise? (I mean, is there a possibility
that the common schematics could still be used for fault diagnosis, despite
the different chip locations)

I wonder why the board layout changed? I mean sure there was a lot of unused
space in yours, but it's not like the production boards were physically
smaller. I'm surprised that additional space couldn't have been used for
some other potential future purpose - RAM expansion or whatever.

cheers

Jules