My Mac SE/30 Part VI: SCSI2SD Installation

In Part V of this series I upgraded the RAM and ROM in the vintage Macintosh SE/30 that I’ve been restoring. In this post, I replace the old dead hard drive with a modern SCSI2SD.

As mentioned in Part II, the hard drive that came in this machine was a 426 MB Segate ST1480N, an upgrade from a previous owner. It doesn’t boot anymore but that’s no surprise – it’s 27 years old at this point. I tried hooking it up to my bridge Power Mac 8600/200, but it didn’t even recognize a drive was connected.

In any case, my plan was always to replace the drive in this SE/30 with a SCSI2SD, which, if you aren’t aware, is a modern device that can simulate one or more SCSI drives using an SD card for storage:

Mounting options

I’ll cover setting up the software side of the SCSI2SD in a later post, for now, the goal is just to get it physically installed and hooked up where the old hard drive used to be. At first glance, it seems pretty straight-forward, but there’s a few minor problems.

First off, the original hard drive screws into the sides of SE/30’s metal drive caddy, and the SCSI2SD only has bottom mounting screw holes. Given that the SCSI2SD is just an exposed circuit board, even if you could mount it, you wouldn’t want the metal caddy to short anything underneath the board.

Secondly, the original hard drive was oriented such that the side with the SCSI port was to the rear of the machine. If I mount the SCSI2SD the same way, then the side with the SD card and USB port will be pointing inside. One of the main reasons I want to use the SCSI2SD is to be able to easily access the SD card to transfer files, make backups, or even swap it out for testing alternate cards. As-is, I’d have to take the case off every time to get to the card, or to connect a USB cable to configure the device itself.

Thankfully, Colin from This Does Not Compute solved both of these problems by designing a custom SCSI2SD Bracket for the Mac SE/30. Instead of mounting to the drive caddy, the 3D-printed plastic bracket mounts to the back of the SE/30’s chassis, and aims both the SD card slot and the USB port out the rear of the case. As detailed in his video, the SE/30 supports expansion cards, and so there’s a small opening in the rear of the case to expose any extra ports those expansion cards might have.

Since I have zero plans for adding any expansion cards, I decided to go with his bracket. He doesn’t sell them but he open-sourced the design, and since I don’t have a 3D-printer of my own, and since this was my first ever time needing a 3D-printed part for a project, I finally got to see what it takes to get someone else to make it for me.

The process was easier than I expected. After getting a little lost looking at sites that handled bulk orders, I found makexyz, an on-demand service that will forward your job to a local printer to print your one-off part. I just uploaded the STL file, kept the default settings, and in a week or so I got the bracket in the mail:

Extending the LED wire

While I waited for the bracket to arrive, I set to solving another problem. The SE/30’s case has small LED in the front that wires to two pins on the hard drive in order to show disk activity. The SCSI2SD does have pin holes for an activity LED, however with the SCSI2SD flipped around, the original wire doesn’t reach.

Wanting that LED to be functional, and not wanting to modify the original wires in any way, I finally invested in a set of various connectors and crimps and made a custom “extension wire”:

I also added a matching header to the SCSI2SD board. Hooking up the LED is very much optional, but I was positively ecstatic to see it flashing when all was said and done. But I’m getting ahead of myself.

Minor bracket adjustments

When the bracket arrived, it came time to actually install it into the machine. However I hadn’t noticed that in Colin’s setup he had removed the original hard drive caddy in order for his bracket to fit. I, on the other hand, intended on leaving the empty caddy in so I wouldn’t ever misplace it.

This was almost a non-issue, except for one tiny little spot where the bracket and caddy intersected. So I busted out my Dremel and cut a small groove in both the bracket and the SCSI2SD board itself:


With the grooves cut, the bracket cleared the caddy and installed quite easily:

The LED extension wire I made reached perfectly, and looking at the back of the machine, you can see where the bracket mounts to the expansion port slot to expose the SD card and USB port.

But now there was another problem. The SCSI port on the motherboard is near the rear of the machine, very close to the original hard drive’s port. As such, the original SCSI cable was very short, and though it’s kind of hard to see, it’s now stretched to its absolute limit to reach the port on the backwards SCSI2SD.

Not wanting to add any unnecessary strain on the parts, I went and ordered a new longer cable. And by new, I actually mean new! I assumed since SCSI cables aren’t used anymore I’d have to buy an old one, but I was happy to find someone making brand-new SCSI cables in various lengths. It worked perfectly:

The last thing to do was connect power. Now, the SCSI2SD can be powered one of three ways: directly over the SCSI cable (if the motherboard supports it), via USB (if you really want to run a cable there) or via a standard floppy power-cable.

While technically the device draws way less power than a traditional hard drive, and could therefore probably run off just the SCSI cable, I wasn’t sure that the SE/30 motherboard supported and I happened to have a spare Molex-to-floppy power adapter handy. So it was easy enough to continue using the existing hard drive power cable to power the SCSI2SD instead:

With the SCSI2SD installed, my planned hardware upgrades were complete. While there’s still work to be done inside, such as re-capping the analog board and completely cleaning and greasing the floppy drive, for now, it was finally time to close up the case.

I popped off the small door to the rear expansion slot (and taped it inside the case so I wouldn’t lose it), so here you can see the final result from the rear:

I think it looks quite clean, and since it’s recessed inside the case, it’s not immediately obvious that it’s even in there. The SD card sticks out a bit but doesn’t clear the case, so there’s little risk of accidentally bumping it.

That’s it for now, stay tuned for Part VII, where we finally turn to the software-side of restoring this machine.


Want to read from the beginning? Start at Part I.

9 thoughts on “My Mac SE/30 Part VI: SCSI2SD Installation

  1. Great stuff. Loving your upgrades. I’m Looking at adding an scsi2sd to my se/30 although my pds slot is filled with a network card so would look at mounting differently to yours. 1.) are there other 3d printing options you came across?
    I believe you’re limited to 4gb hdd size. have you tried looking multiple operating systems (partitions) so say 16gb formatted into 3 different versions of the OS and 4th being AU/X separately. Do you know how easy that is to configure? Currently i just have 1gb hdd so only the one os 7.5

    1. I don’t know if there are any other 3D printed mounts, only the “official” ones, or people just getting creative with double-sided tape and putting the device where the old hard drive would be. I specifically wanted to expose the card out the back with Colin’s mount.

      You can do multiple virtual drives using the config software, and try to install different versions of the system on each. You just have to do the math and divide up your SD card appropriately. And you can partition drives into multiple partitions as well.

      But honestly, unless you’re doing some kind of retro-only challenge, or just want to see if it’s possible, or are a content-creator wanting to do something crazy, there’s really no need on an SE/30. I have installed tons of compatible apps and games, and I’m using like 350 MB. Really, the speed and screen limit you to a certain class of software, and it’s just to hard to fill up a big drive with it.

      Unless you have an 040 upgrade and a video card for an external higher resolution color monitor, having a single 2GB is already overkill. Plus such small cards are just easier to backup and cheaper to buy in bulk.

      There’s maybe a couple CD games that are B&W (Manhole?) that you could store disk images of. Or if you wanted to keep backups of all the installers for everything you installed. Even then, maybe you could creep up to 1GB.

      If you’re sound/graphics editing extensively, maybe you can push your usage higher.

      With all that, the most I would consider is getting a 4 GB card and mounting 2×2 GB drives.

      1. Hi Jon,
        Thank you for the quick reply. I’m enjoying your series as you restore and upgrade your Se/30.
        I think double sided tape would probably do just fine. I like your solution but didn’t want to loose my network card as i have it fully functional online and networked to a few newer machines making getting software from machintoshgarden and few other sites easy to download from.
        The only reason i asked about the partitioning as there is software and games in OS4-6 that wouldn’t work in 7.5.5 so i thought partitioning maybe an option unless you know of less technical solutions I’ve missed? As for Au/x unix is just an experiment really nothing more. I thought it maybe possible with a switcher on boot up. I’m far from an expert though and just tinkering with ideas for future possibilities which is why i enjoyed reading your article.
        The most i push it is doing some graphic design in photoshop, a fruitless exercise on a 1 bit machine with small screen but surprisingly fun (i trained as a graphic designer on mac in the early 1990’s) mac II’s, Color classic and lc’s so it’s for nostalgia and to see what can be achieved with a mere 1 bit to play with. I take your point with capacity I’ve not used over 700mb so far.
        Keep up the good work on yours, i have a few more on your series to read over the next days so i read with interest on what you manage to do with yours 🙂



      2. AFAIK, the SE/30 needs at least System 6. And in my testing, there was nothing that ran on 6 but didn’t run on 7. Some games require rebooting in 24bit mode on 7, but that’s it. And switching between 6 and 7 is a pain as each system has to rebuild the Desktop file on every drive after switching, which can take several minutes.
        If a game requires something older than 6, then it really will only work on a system that can run on an OS older than 6. Like maybe a SE or Plus.
        So, with all the RAM I have, I wanted the best version of 7, which is 7.5.5. without the ROM upgrade, and just 8MB of RAM, I’d probably stick with 7.1.
        IMHO, if and when I want to use 6 on this machine, I’m fine with booting from floppy or Floppy EMU.
        The only reason I can thing if for installing 6 is if you want a dedicated instant-on machine to go into one app like a word processor. Seriously, 6 on the SE/30 boots to a usable desktop the moment the startup chime finishes.

      3. Ah ok I didn’t know about the 24bit mode. I’m running mode32 with 128mb. I do have a the trick rom but I couldn’t get it to work as I’d already installed up to 7.5.5 and it would have meant a fresh install and i’d got it in s sweet spot. Once i go to scsi2sd I’ll put in the rominator. Do you notice a performance increase using the scsi2sd? Where did you buy it by the way? Been looking on eBay but couldn’t see if it would work on old mac or not

      4. Thanks Jon, yes i have a later 2gb quantum in it at present but worry about it failing even though it appears fine at the moment. I’ll see if they have any available.
        I’m knee deep in cables at the moment. I had to strip the se/30 down yesterday to fix a sound issue and some minor maintenance on my other machines, luckily just a dry joint but took the opportunity today to re-do my tiny hobby room, i have a 1995 6200CD, a 1997 6500/275 and a late 1999 imac g3 400 all networked to the Se/30. I’m struggling getting my scsi chains setup on the se/30 though; a zip drive, 2 x cd-rom and a scanner I’ve never managed to get it all working in 1 chain before. No plug and play in 1989 😆

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