John's Port-Powered Midi Interface for the Macintosh - Part 3
Jean-Yvan's modification


Check this out! Jean-Yvan Fradet from Canada took my main board and the 2/4MHz auxillary board and squished them into one board, the same size as my original! Who would have thought this would become such a multinational effort?

It may be a bit of a tight fit and there are heaps of links so if you are going to use this approach you need to be very careful not to forget any of the links and make sure there aren't any shorts.

Here's his design (click on it to download a PICT version)....

And the copper side...

There are only the two additional components, apart from links, compared with the original board. These are...

  • C5: 0.1uF
  • U3: 4013 dual D flip flop

Also note the extra bridged tracks under the board and that several of the original components are in different positions. All that's left to decide is which output to HSKi (Pin 2 of the mac socket) to use. If your crystal is 2MHz, use A1. If it's a 4MHz one, use A2.

You may notice that by reducing the length of one of Jean-Yvan's links (the one to the immediate left of C4) you can eliminate the other link (to the right of C4) but either way it will work.


This page is maintained by:

John Loadsman,
Department of Anaesthetics,
Royal Prince Alfred Hospital,
Camperdown, Australia, 2050
Fax +61 2 9519 2455
Telephone +61 2 9515 8564

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