Macintosh Floppy Disk: Does not eject

[Mark Hatzilambrou]

I have a Mac IIsi with a factory installed Sony floppy drive,
and some time ago it decided to completely stop ejecting disks.
My only recourse is to use a paper clip.

It seems to me most likely that the eject motor is bad, but I
can't be sure that it isn't a bad control chip. I don't have
a schematic, and haven't been able to do any course diagnostics
on the parts of the drive by swapping in known good parts (mainly
because everyone I know who has this type of drive refuses to let
me experiment with their stuff, which is reasonable), but I have
swapped a complete new drive, and it appears to work fine.

So my questions are 1) is anyone familiar enough with the Sony drives
in the Mac IIsi's circa 1991 to help me with this? and 2) where can
I get parts for this drive?

Thanks very much.

----------------------
Mark Hatzilambrou
ha...@eecs.berkeley.edu
(510)642-7156
Cory 550-C7

[Jonathan N. Deitch]

ha...@jitterbug.eecs.berkeley.edu (Mark Hatzilambrou) writes:

>I have a Mac IIsi with a factory installed Sony floppy drive,
>and some time ago it decided to completely stop ejecting disks.
>My only recourse is to use a paper clip.

>So my questions are 1) is anyone familiar enough with the Sony drives

>in the Mac IIsi's circa 1991 to help me with this? and 2) where can
>I get parts for this drive?

First, find a drive with dead heads somewhere (check your local computer
stores) and buy it for $10 or so. It doesn't matter if it's a high
density or low density drive.

Or find a good one from a known good drive (buy someone dinner or something).

Now remove it's eject motor and try it on your drive. If it works, your
eject motor is bad. Now comes the interesting thing :

Sometimes those eject motors get jammed. You've got a motor turning three
gears, the last of which has an end-of-stroke switch and a pin which pushes
the disk carriage. Your EOS switch may be screwed and the drive can't find
its 'down' position, or the gearage may be jammed up.

Pop the top off (carefully) and disassemble. Then reassemble and see what
happens.

Good Luck !

- Jonathan
--
mus...@gsusgi2.gsu.edu | "I Hate it when I can't trust | Atlanta 1996 !!
jde...@aol.com | my own technology!" - LaForge | Play Pinball !!
jde...@gisatl.fidonet.org |--------------------------------------------------
--------------------------- "Thrills! Chills! Magic! Prizes!" -- Hurricane

Gene Roddenberry, Isaac Asimov, Jim Henson, Dr. Seuss, Mel Blanc ... Sigh ...

[PDP11 Hacker .....]

In article <2ut9bg$2...@agate.berkeley.edu>, ha...@jitterbug.eecs.berkeley.edu (Mark Hatzilambrou) writes...

>I have a Mac IIsi with a factory installed Sony floppy drive,
>and some time ago it decided to completely stop ejecting disks.
>My only recourse is to use a paper clip.
>
>It seems to me most likely that the eject motor is bad, but I

You can remove the eject motor assembly from the drive (unplug 1 connector, and
remove a couple of screws), and try the motor on an external power supply. I've
never had one fail though.

What I have had fail, and what causes this fault, is an open-circuit
motor-drive transistor on the logic board. Trace back the tracks from the eject
motor connector until you come to a little surface-mount transistor. That
tends to fail. I replace them with a BD131 (3A power transistor) soldered onto
the original pads, and have no further problems.

>
>Thanks very much.
>
>----------------------
>Mark Hatzilambrou
>

-tony

Bristol University takes no responsibility for the views expressed in this
posting. They are the personal views of the user concerned.

[stu...@kuhub.cc.ukans.edu]

In article <2ut9bg$2...@agate.berkeley.edu>, ha...@jitterbug.eecs.berkeley.edu (Mark Hatzilambrou) writes:
> I have a Mac IIsi with a factory installed Sony floppy drive,
> and some time ago it decided to completely stop ejecting disks.
> My only recourse is to use a paper clip.
>
> It seems to me most likely that the eject motor is bad, but I
> can't be sure that it isn't a bad control chip. I don't have
> a schematic, and haven't been able to do any course diagnostics
> on the parts of the drive by swapping in known good parts (mainly

usually the drives won't eject because of solidified grease and
dust buildup. I maintain macs here at the university, and I
dont' think I've ever seen a bad eject motor or chip.

stu...@cs.ukans.edu

[jfilner]

I've seen this alot with 400K drives, but it can happen to
those 800k's as well. The lubricant on mechanism can freeze up with
age. The solution was to clean the mechanism with Freon (you might
want to find another solvant.) and then regrease. After the first
freeze up they tend to need to be regreased periodically, but it does
not take very much time.

End of line...
(jfi...@reed.edu)