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400KB Drive Comparison

This document provides a quick visual comparison of the 400KB floppy drive mechanisms used in the Apple Lisa 2 and the Apple Mac 128/512K.

The drive labelled "Sony" and dated "November 1983" was temporarily removed from my Apple Lisa 2. The second drive was removed from an external Macintosh 400KB drive case; it is the 400KB drive mechanism that I have seen most often but I am happy to be corrected if anyone can show that the other design is more common. The external cable was left on the Mac drive and it is marked only by a simple paper label "Asco October 1985".

The 400KB Lisa drive in its cage.

A nice view of the bare Lisa 400KB mechanism. Note the additional pedestal feet that fit the drive into its cage in the Lisa.

A closeup of the Lisa drive showing the eject mechanism, Sony label and the pedestal feet.

From the top, there are few differences between the Lisa (shown) and the Mac 400KB drives.

Differences between the two drives are more evident when viewed from the rear. Without the benefit of a ruler or calipers, it is unclear whether there are any static dimensional differences.

The Mac drive is on top.

The rear and one side of the two mechanisms. Again, the Mac drive is on top.

A side-on view of the two mechanisms shows clear differences. Both drives are labelled with the month of manufacture.

The opposite side has also been completely re-engineered. Even with my lousy photography, it is clear that none of the mechanical components are interchangable between the drives.

Other Sources of Information

Eric Rasmussen describes two types of 400KB drive used in the Mac at his excellent Apple Macintosh before System 7 site.:

"There were two basic types of disk drives:

Early Sony model OA-D34V.
Later Sony models OA-D34V-02 or OA-D34V-22. These models had a new insert/eject mechanism. July 1984?"

To be added: Any useful notes from Larry Pina.

Can you help?

If you have owned your Mac 128, Mac 512k or Lisa 2 from new, I'd like to know which of these two drives was fitted to your computer. Please mail me, Phil Beesley, at beesley@mandrake.demon.co.uk.

Copyright information: If you wish to use any images on these pages, please contact the author, Phil Beesley on beesley@mandrake.demon.co.uk.

The 400KB Lisa drive in its cage.	A nice view of the bare Lisa 400KB mechanism. Note the additional pedestal feet that fit the drive into its cage in the Lisa.
A closeup of the Lisa drive showing the eject mechanism, Sony label and the pedestal feet.	From the top, there are few differences between the Lisa (shown) and the Mac 400KB drives.
Differences between the two drives are more evident when viewed from the rear. Without the benefit of a ruler or calipers, it is unclear whether there are any static dimensional differences. The Mac drive is on top.	The rear and one side of the two mechanisms. Again, the Mac drive is on top.
A side-on view of the two mechanisms shows clear differences. Both drives are labelled with the month of manufacture.	The opposite side has also been completely re-engineered. Even with my lousy photography, it is clear that none of the mechanical components are interchangable between the drives.