Colour Classic hard drive replacement

A write-up of a successful operation

As I mentioned in my previous entry, a couple of months ago the hard drive of my Colour Classic stopped working. Despite not having a replacement ready, I wanted to extract the drive to attempt a move that proved to be useful in other similar circumstances: inserting the drive in an external enclosure and connecting it to the Mac, in this case via SCSI.

When I acquired the Colour Classic some seven years ago, I opened it to examine the conditions of its entrails, and noted that the hard drive looked rather reachable. Good thing — I thought — so it won’t be a problem the day I need to replace it. Well, in hindsight I guess I underestimated the situation.

When you own a few vintage Macs, the sensible thing to do is looking for their service manuals, easily found on the Web in electronic format. When I started the hard drive extraction, I basically knew where to put my hands once removed the Colour Classic’s rear housing, but I wanted to take a peek at the service manual anyway. To my surprise, the hard drive replacement procedure was more complex than I expected:


I really, really did not want to remove the anode cap and analog board. The manual explained the procedure very well and I’m expert enough to manage the task, but I didn’t want to dismantle half Colour Classic just to get to the hard drive, which still seemed reachable to me without messing with the CRT. So yes, there is a shortcut, but you have to get ready for a ‘blood, sweat and tears’ situation.

The following is a photo of the hard drive as seen when you remove the rear housing (it’s actually a photo I took after inserting the working hard drive Grant shipped to me):

Colour Classic hard drive
Not exactly within reach

It is quite recessed, the approximate distance being 10 centimetres. Let me tell you, the space is cramped and there isn’t much room for operation with your hands (and I have slim hands with long fingers). Disconnecting the data cable is the easy part: you grab the flat grey surface and pull. It usually comes out rather gently. The power cable, on the other hand, is the true son of a bitch. (It’s that semitransparent piece of plastic with the four coloured cables coming out, in case you don’t know). These hard drive power cables have always given me a hard time with vintage Macs, no matter the reachability of the drive. They are inserted very tightly and they’re hard to very hard to pull out.

I usually resort to some small pliers my grandfather used when assembling ship or plane models. They’re effective and can usually reach their target even when there’s not much room. But the Colour Classic’s hard drive was too recessed and the vertical room simply insufficient to try any other tool that wasn’t my fingers. After a few painful attempts, I decided to wait for the new hard drive to arrive. Meanwhile, my friend Morgan Aldridge tweeted a good piece of advice: use power cable for upward lift while releasing the tab.

The tab he’s referring to is this:


I am always wary when pulling cables by grasping the cables themselves instead of their plugs, but in this case they were so strong I just went with it, and the effort paid, because I managed to pull the hard drive closer towards me. Then began the painful attempts at disconnecting the power cable. I tried various pliers until I found suitable ones, and after resorting to brute force I successfully disconnected the power cable and was able to pull the hard drive out completely:

Colour Classic hard drive out
It turned out to be a Quantum ProDrive ELS (80 MB)

As I was desperately trying to disconnect the power cable trying different positions and techniques, I couldn’t help but think that I would have probably been better off following the longer and more complicated procedure outlined in service manual. This is the first case of some component replacement where I found that an alternative route is possible, although it turned out a bit less comfortable than expected. I still think I made the right decision, anyway, since I really don’t like operating on parts of, or connected to, the CRT.

Replacing the hard drive was the first step. Now I needed to boot the Colour Classic and reinstall the operating system. Although the Colour Classic supports up to Mac OS 7.6.1, I always used System 7.1 on it. It offers a stable environment, it doesn’t use too much RAM (which is always a rare resource on the Colour Classic — handling a maximum of 10 MB, it’s not the most expandable compact Mac), and the overall performance is decent.

I own a full set of System 7.0.1 and System 7.1 original floppies, and I thought I had used the 7.1 ones to install the OS the first time after acquiring the Colour Classic. But when I rebooted the Mac from the Install Me First floppy, after the Happy Mac icon, I got this warning: This startup disk will not work on this Macintosh model. Use the latest Installer to update this disk for this model. (System 7.1 does not work on this model; you need a newer version that does.).

Strange, I thought, since I was using System 7.1 on the Colour Classic before the hard drive incident. Then I remembered: the Colour Classic is one of those vintage Mac that needs a System Enabler to work with System 7.1. So I had to prepare a custom boot floppy with a minimal System 7.1 installation plus the System Enabler 401. Furthermore, since I also own an LC 575 motherboard (which is identical and therefore easily swappable with the original Colour Classic’s but gives you a faster processor — a 68LC040 at 33 MHz — and supports RAM up to 68 MB), I needed to put on the custom boot floppy also the modified System Enabler 065 that lets me use the LC 575 motherboard in the Colour Classic without resorting to the VGA modification. (This is usually called the ‘Mystic’ upgrade. More information here).

The System Enabler 401 can be downloaded at this Apple support page (a must-bookmark). Then I took the Disk Tools floppy from the System 7.1 set of diskettes: it contains everything you need to boot your Mac in System 7.1, plus the disk tools: Disk First Aid and Apple HD SC Setup. I made a copy of the disk and I didn’t have to delete anything to save space: in the 288 KB available I could easily fit the two System Enablers. When the custom disk was ready, I inserted it in the Colour Classic and rebooted successfully. On the hard drive Grant sent me there was already a System 7.1 installation (even some applications and games, whee!), so it was only a matter of copying the Enablers in the System Folder on the hard drive and reboot again. Now the Colour Classic is up and running again.

Colour Classic up and running
Mission accomplished.

In the next days I will restore the contents of the old hard drive (what I had from the last backup I did before the incident) and see if it powers up using an external SCSI enclosure. It’s nice to have my vintage writing machine back! Thank you to all those who helped, directly and indirectly, and who followed my little adventure via Twitter.


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