Power Macintosh 5400 from 1996: How to recover files?

Hi,

Using an IDE/ATA to USB bare drive adapter should work. However, since the System 7.5.x hard disk has a plain HFS (not HFS+) file system, a Windows 7 computer will not be able to read it without a special Mac-disk utility capable of handling HFS (something like an appropriate version of MacDrive or TransMac).

Alternatively, it should be possible to install a small FTP server (for example, the now free NetPresenz) on the 5400/120.

The following article could perhaps be of interest to you: https://happymacs.wordpress.com/2014/07/09/networking-your-classic-macintosh-with-windows-part-3-using-netpresenz-and-fetch/

An FTP client on a modern computer could then access files via Ethernet and the local network.

If you have to download Mac application files for use on the 5400/120, make sure to keep them unaltered until on the old Macintosh computer. Such files are typically encoded MacBinary (.bin) or BinHex (.hqx) for protection. Do not try to decode or decompress anything until on the 5400/120. Once there, use StuffIt Expander (an existing ready-to-use version like 5.5, or possibly 4.0.1). If necessary, you could use CD-R discs in an ISO format for transfers to the 5400.

Power Macintosh 5400/120: Technical Specifications

http://manuals.info.apple.com/Apple_Support_Area/Manuals/desktops/0340002APM5400UMRV.PDF

Welcome!

I tried using an IDE->USB adapter...

That IS the easiest way.

1) Does the adapter work properly with other drives? I have one where the required power cable connector has a loose pin and I have to be careful how I plug it to the drive. You DO have the four-pin, adapter-to-drive power cable, right?? The one in the OWC adapter kit looks like this:

[from this page: https://eshop.macsales.com/item/NewerTech/U3NV2SPATA/#includes ]

Powering a 3.5-inch drive may vary with make/model of adapter.

2) Are you sure the drive is functional? Can your hear it spin up? That computer model was discontinued in 1998 and, if the drive had been unused for a long time, its bearings could have seized or moisture could have compromised the internals.

There are limitations regarding the plain HFS (Mac OS Standard) file system even for modern Macs. macOS 10.13 High Sierra or macOS 10.14 Mojave (but not later systems) should still be able to read HFS.