Re: IIGS Drive Questions

[Gary Gouriluk <gvgouril@shaw.ca>]

I don't have the clicking on my ROM 3, but remember having it on my ROM 1. I think
I eliminated it by going to the finder preferences and turning off checking the
5.25 drives....or maybe I'm just thinking of the also annoying grind of an empty
5.25 drive. Or maybe I just kept a ProDos disk in all my drives, so the clicking
would stop. Anyway, I am sure glad my Rom 3 doesn't do it.

Gary


David Empson wrote:

> Juspion2002 <juspion2002@aol.com> wrote:
>
> > I just got a IIGS yesterday and have run the different system disks it came
> > with.  My question is why once the disk loads the GS/OS and is on the desktop,
> > I hear a light ticking sound coming from the CPU.  I have two 3.5 drives and
> > two 5.25 drives hooked up and I notice every time the system ticks, the 5.25
> > drive lights blink.
>
> This is caused by the Finder polling the 3.5" drives to see whether you
> have ejected or inserted a disk.  The polling consists of selecting the
> drive and reading a flag bit (it doesn't need to activate the drive
> motor).
>
> The select line is shared by the 5.25" and 3.5" drives, and there is an
> "enable 3.5" output which causes the 3.5" drive to cut off the
> daisy-chained enable signal to the 5.25" drives, but it cannot do this
> fast enough to avoid a brief pulse on the LED of the 5.25" drive.
>
> The sound you are hearing is due to electrical noise on the +12V rail
> (or possibly the +5V rail) leaking into the sound circuitry.  The ROM
> 00/01 IIgs is most affected by this: the ROM 3 has improved sound
> circuitry which is much less susceptible to noise.
>
> --
> David Empson
> dempson@actrix.gen.nz