2 Aug
2010
2 Aug
'10
12:28 p.m.
Tony wrote:
> One thing to watch for are the little 20-way Apple
ribbon cables that
> link these drives to the mainboard. They are not what they seem -- in
> particlar 1 ro 2 wries are not wires at all, but solid plastic, so those
> pins of the connectors are not linked. If they are, then all sorts of odd
> things happen (Eject motor runs continuously???)
>
> I beelive there are at least 2 versions of the calbe (for double sided
> and high density drives>?, with different coloured pin 1 tracers. A Mac
> enthusiast may know more.
>
Jeff wrote:
I don't remember all the details. I do remember
that there is a cable
with a yellow stripe on pin 1 and another version of the cable with a red
stripe. If you install the wrong cable (can't remember whether it's red
for yellow or yellow for red) the eject motor does indeed run
continuously.
It doesn't seem to damage the drive; I never let it run more than a few
seconds. So it's easy enough to identify and correct.
There's a dedicated eject signal on the 800K and FDHD that will cause
the drive to eject. IIRC it is active low, and replaced a ground. The
internal drive connectors in the Mac are not wired for that eject signal.
The dedicated eject signal is probably used in the external drive
enclosure for the eject button. Software can tell the drive to disable
the manual eject and poll the button instead. Or something like that.
Eric