Macintosh Portable

drlegendre . drlegendre at
Sat Nov 26 03:52:35 CST 2016

I can't answer your question about PSU polarity, but I do have some
experience with the Mac Portable hard drive. I had to 'make' a replacement
drive for one, almost 20 years ago now.. so forgive me if there are errors
in this!

You're correct about the drive connector, it's one of those maddening
proprietary things that Apple was and still is prone to doing. If I recall,
the drive itself uses the standard SCSI interface, but the stock drive has
a permanently attached cable with its own pinout. And I think the drive
cable carries both data and power.

If you can find the +correct+ 20 or 40MB (?) Conner hard disk, you can make
a cable that allows you to use one as a replacement for the stock drive,
which is very prone to failure. Apparently, the stock drive is a low-power
version of the otherwise identical Conner drives available at that time.
The stock drive has a red label, and if I recall, the similar but
not-low-power drive has a green label. So the common green-label drive
works fine, but it will consume more battery than the special low-power

Point is, if it still exists, find the web page that shows how to make &
wire the adapter cable - and that should give you enough info to create a
data & power cable that will allow you to read the stock disk.

There was also some talk, at the time, that it was possible to transfer the
complete circuit board, with cable, to one of the green label drives.. and
have it work. Of course, this would only work if the drive had a physical
failure, rather than a failure with the board electronics. In my case, I
had to wire up a special cable.. it took a couple hrs, but worked fine.

On Sat, Nov 26, 2016 at 12:26 AM, Chris Pye <pye at> wrote:

> Does anyone know off hand what polarity that Mac Portable requires? I know
> that the original was 7.5V @ 1.5A, but not sure of the polarity.
> I did have have a PB100 power supply that I used with mine, but
> (unfortunately) no longer have it.
> Also (if it still works) what is the easiest way to image the old Conner
> SCSI drive? It doesn’t appear to have a standard connector.
> I have googled this, but didn’t come up with anything useful.
> Thanks,
> Chris...

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