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From: trewitt@cascade.Stanford.EDU (Glenn Trewitt)
Newsgroups: comp.sys.mac.hardware
Subject: Re: No Disk Eject in 512K Mac
Message-ID: <1335@cascade.Stanford.EDU>
Date: 14 Jan 90 18:27:53 GMT
References: <2713@ucsfcca.ucsf.edu>
Sender: trewitt@cascade.stanford.edu (Glenn Trewitt)
Reply-To: trewitt@miasma.Stanford.EDU (Glenn Trewitt)
Distribution: na
Organization: Stanford University, CIS
Lines: 66

In article <2713@ucsfcca.ucsf.edu> paul@ucsfccb.UUCP (Paul Green) writes:
>A collegue has an old Mac 512K (upgraded from a 128K)
>which has recently developed a problem in ejecting
>floppy disks. Both his internal and external floppy
>drives no longer eject disks, but he is still able to
>by sticking a paper clip in the manual ejct hole. He
>says that he hears a mechanical noise when the Mac is
>"trying" to eject the disks.
>
>Does anyone have an idea what has happened? Is it coincidental
>that both internal and external drives have malfunctioned at the
>same time?
>Any information will be gratefully received, Thanks!

It's coincidental, but not at all suprising.  It's an age-related
failure caused by the grease solidifying.  Perhaps temperature-related,
but that's unimportant.

(I've fixed this problem in about a half-dozen 400K drives for friends
using the method below.  Other followups have said that the springs get
weak or that the eject motor is disconnected.  I've never seen either
of those situations.)

It is VERY common for old single-sided drives to not eject disks.  The
lubricant (grease) solidifies to the consistency of ear wax.  What
I've found to work is to take the disk drive out of the Mac (or
external box -- they are identical) and clean it out using acetone.
I've found that it's easiest to do by removing the sliding mechanical
part of the disk-handling mechanism and immersing it in acetone:
This mechanism is on the right-hand side of the drive (viewed from the
front) and includes the bar that you push a paperclip against to
manually eject a disk.

0)  Play with the insert/eject mechanism to understand how things work.
	Especially, note the action of the little-bitty cam widget near
	the back of the mechanism.  This is what's really sticky, and
	it's very hard to clean without removing the mechanism.
.1) Observe the small nylon (white) cam that rides the top surface of
	the diskette case.  It's purpose is to slow down the disk upon
	eject so that it doesn't fly across the room.  Note its
	orientation -- it's easy to get it wrong when reassembling.
1)  Remove the (large) C-clip holding the eject bar to the eject motor cam.
2)  Remove the two screws on that side that hold the mechanicism to the
	main assembly.  (it's beginning to get really loose now)
3)  From the bar that extends across the width of the drive, remove the 
	(small) C-clip on the right-hand side.
4)  Slide the bar out 1/4 inch.  The mechanism will now come loose.
5)  (optional, but very helpful) Disconnect one end of each of the two
	springs.  (One end is crimped closed; detach the other end.)

Soak the mechanism in acetone in a ceramic or metal dish and manipulate
the mechanism to work the grease loose.  Change the acetone and repeat.
Let the mechanism dry out completely (a hair dryer may help here).
After it's dry, check for smooth operation; repeat cleaning if
necessary.

I've just used WD-40 to lubricate the thing, allowing the volatiles to
evaporate completely before putting a disk in.

Reassamble in the reverse order.

	- Glenn Trewitt
-- 
Glenn Trewitt, Center for Integrated Systems, Stanford University
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