5 Mar
2011
5 Mar
'11
9:04 a.m.
--- On Sat, 3/5/11, Tony Duell <ard at p850ug1.demon.co.uk> wrote:
One thing to watch for when working on older Max is
that
the floppy drive
ribbon cables are not necessarily what they seem. It make
look like a 20
pin ribbon cable, but if you examing it you will find that
a couple of
'wires' are jsut plastic, no conductor. Thos pins are not
connected (they
have signals on both the drive and logic board headers, but
not the same
signal, they muc not be joined). This led me a merry
dance....
It depends on the machine and the configuration. IIRC, the earlier machines had regular 20
pin cables, but then certain combinations of disk drive and computer needed the
"yellow stripe" cable, as opposed to the "red stripe" one.
You can use the 800k drive on a machine that needs a 400k drive by clipping pin 20 on the
cable, if I'm remembering that right. That is the PWM line. If you leave it connected,
you get constant ejecting.
I also seem to remember something about pin 9 needing to be disconnected as well, but I
can't for the life of me remember what that was.
A similar trick was needed to use an 800k drive on a machine with a SuperDrive controller
(MacII, etc)
-Ian