Possibly rarest Apple 1 ever for auction

Tothwolf tothwolf at concentric.net
Sat Jul 23 09:20:24 CDT 2016

On Sat, 23 Jul 2016, Corey Cohen wrote:

> My guess is that is was a test board for Apple.  There are some weird 
> mods to the ram timing with a variable cap and to the negative supply 
> that looks like they were experiments to figure out the tolerances of 
> the chips.  The board was wave soldered.  You can't fake that on an 
> Apple-1 because of what happens to the back of the board by the 
> regulators. [...]

If you mean the crinkle tin plate under the solder mask, that doesn't 
happen due to wave soldering. The heavy tin plate was applied that way in 
a separate process before the solder mask was applied to the board. It 
used to be common to do that to all sorts of boards in the 1970s-1980s. 
With modern boards, is much more common now to just leave exposed 
copper/gaps in the solder mask and allow those areas to take up solder 
from the wave soldering (or reflow) processes.

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