Date   : Sat, 18 Apr 2009 19:14:17 +0100
From   : zeem.uk@... (Alex Taylor)
Subject: Easter Disaster

2009/4/18 Andy Ford <acorn@...>:
>
> The keyboards are different in that a B has a single connection of about
> 17 pins and the Master has two sets of 15, I am going from memory here
> so those numbers may not be 100% correct.

There's a place on the Master PCB for a pin header which isn't
normally fitted. It's just below the keyboard connector and connects
to many of the same PCB traces. I never noticed it before, until
someone on the list briefly mentioned its existence, and something
about its use for connecting up a Model B keyboard.

> As for length, I'd (guess) you could get away with 30cm (possibly less)
> without issues. You can use something like an old IDE cable if you
> needed a length of suitable cable though, saves buying a (possibly)
> expensive ribbon cable.

I did once use a standard IDE cable when testing a load of hardware on
a Model B. It meant I could run the machine with the keyboard out of
the way of the ROMs, so I could test a bunch of them without having to
move the keyboard out of the way between each operation. I've killed a
Model B before when doing such a thing loosened the solder joints on
the keyboard's connector, which after time broke the motherboard.

> I do have a spare complete Master Compact keyboard in my spares,
> although I am not sure if that would fit a Master or not

> I doubt it due to the extra keys, untested
> though (no Compact to test it with)

Don't the Master and the Compact have the same keyboard? I've only
ever seen one Compact in the flesh, that was for sale many years ago
in a computer shop and I couldn't afford it at the time.

-- 
Alex Taylor