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How to make a Mac Plus clock

By Benj Edwards
Macworld DEC 28, 2012 3:26 am PST

Just over a quarter century ago, Apple factories began pumping out Macintosh Plus computers by the tens of thousands a year, and they continued that pace for four years straight. As a result, this 26 year-old computer model is one of the most plentiful vintage compact Macs you’ll find out in the wild. That makes it a ripe platform for experimentation.

You can do many things with a Mac Plus. You can gut it and turn it into an aquarium or a modern PC server. You can actually use it for word processing, a task at which it still excels. Or, if you’re like me, you can turn it into a clock—a Macinclock.

If you have a spare Mac Plus sitting around, a blank floppy disk, and the right software, you too can have your very own silent Mac Plus clock.

Technically, any compact Macintosh could serve as a clock, but the Mac Plus is the most attractive target because, when booted from a floppy, the Mac Plus clock will be completely silent. That’s thanks to the Mac Plus’s lack of an internal cooling fan—something Steve Jobs insisted upon for the original 1984 Macintosh model that carried over to the Plus.

What you need

  1. A working Macintosh Plus.

  2. A new Macintosh PRAM battery (optional). The Mac Plus uses a 4.5 volt Eveready 523 battery to power its internal clock. This keeps the correct time if the system gets unplugged from the wall. You can buy a new one from vendors on Amazon.com, among other places.

  3. A Mac with a floppy drive and Internet or ethernet access to serve as a file transfer bridge, or an Internet-capable Windows PC with a floppy disk drive and a Mac with a 1.44 MB SuperDrive.

  4. For the uninitiated, these are what 3.5-inch floppy disks look like.

    One blank 800K double-sided, double-density (DSDD) 3.5-inch floppy disk. You need an authentic DSDD disk too. Try eBay. Don’t bother trying to use a 1.44MB disk on the Plus. If you format it as an 800K disk, it will probably only work a few times then give up the ghost.

  5. The HappyPlusClock software. The software that makes the Macinclock possible is called HappyPlusClock. Aaron Hall, a Washburn University systems administrator, wrote the software in 2007 as his entry in the 2007 Retro Challenge contest (it won). I’ve prepared a bootable 800K disk image of the software, and you can download it here, or you can download the software from the HappyPlusClock website ( v0.86 mirror).

  6. Apple Disk Copy 4.2 (for 68K Macs) or Disk Copy 6.3.3 (for PowerPC Macs) software. This writes the HappyPlusClock disk image to an 800K floppy. You can download both versions from Apple’s support website.

Transfer instructions

Technically, it is not hard to run the HappyPlusClock software. But it is difficult to download that software from the Internet and transfer it over to a Mac Plus. So unless you’re one of the ten people on Earth with a Mac Plus SCSI-to-ethernet adapter, you’re going to need a bridge machine of some sort—either an older Mac with a floppy drive and an ethernet card, or a Windows PC with a floppy drive and an older Mac with a 1.44MB floppy drive (called a SuperDrive in the parlance of the day).

There are probably dozens of other ways to transfer the software to a Mac Plus disk based on various configurations of Macs, networks, storage media (CD-ROM is another possible conduit between modern PC and vintage bridge Mac), and other factors—enough to fill a book—so I am only going to cover the most common transfer and setup methods below.

If you have an older Mac with a floppy drive and an ethernet card: Congratulations. This will be easiest for you, Obvious Mac Collector. Hopefully your ethernet-enabled bridge Mac is hooked to the Internet. If so, simply open a Web browser on that Mac and download the HappyPlusClock software from this link. Extract the software with StuffIt, copy it to a bootable 800K disk, pop it in your Mac Plus and you’re done.

Alternately, load up Disk Copy and write the HappyPlusClock disk image provided above to a disk.

If you don’t have a Web browser on that older Mac, get one, or download HappyPlusClock on a modern computer and copy it to that Mac via AppleTalk (beyond the scope of this article) or by setting up an FTP server (also beyond this article’s scope).

If you have a modern PC with a floppy drive but no bridge Mac: If you don’t have an older Mac with a 1.44MB floppy drive to use as a transfer bridge to the Mac Plus, there is still hope. You can possibly transfer the software over to a Mac Plus with a serial cable.

Of course, you’ll need the appropriate serial adapter on the Mac side, the proper null modem cable, working terminal software on both the Mac Plus and modern PC side (with file transfer capability), and quite possibly an external SCSI hard disk for your Mac Plus for working room to pull it off. This is where things get complicated, and if it’s this hard, you probably shouldn’t bother. But the option is always there for the persistent.

If you have a modern PC with a floppy drive and an older Mac with a 1.44 MB floppy drive: First off, it’s worth mentioning here that the Mac Plus floppy drive can’t read 1.44MB high density floppy disks. It can only read 800K (720K on IBM PCs) double-sided, double-density (DSDD) floppies and the older 400K disks used on the first Mac.

That means you can’t just write a floppy on your Windows or DOS-based PC and stick it in the Mac Plus. It’s not physically possible because of the variable speed voodoo Apple engineers built into 800K floppy drives.

So you will need not only your Mac Plus, but also an older Mac with a 1.44MB SuperDrive. To make things even more complicated, that older Mac will also need software that allows it to read MS-DOS format disks. I believe later versions of the classic Mac OS shipped with this functionality built in, but if not, ask around for the File Exchange control panel.

If you have all that set up, then download the software above to your PC and copy whatever you can fit onto your 1.44MB disk, making multiple copy trips if necessary to offload the data onto your bridge Mac.

Then you’ll hit another roadblock. You’ll find that you’ve broken the Mac file resource forks for the Disk Copy binaries. You’ll need MacLinkPlus to heal them. If you already have Disk Copy working on the bridge machine, then the HappyPlusClock disk image should still work without its proper resource fork in place.

Once you’ve got the HappyPlusClock disk image and Disk Copy 4.2 or 6.3.3 software on your bridge Mac, start Disk Copy and write the HappyPlusClock image to a blank 800K floppy. (Disk Copy 4.2 works better on Macs with 68K CPUs, and 6.3.3 is best for Macs with PowerPC CPUs.) Then stick the floppy into your Mac Plus and it should boot right up.

If you only have a Mac Plus and no bridge machine whatsoever: You’re going to have to convince someone to give you an 800K floppy with HappyPlusClock already on it. This is a particularly authentic transfer method, because it is exactly how software distribution worked in the days of the Mac Plus.

Using the software

Once you have the HappyPlusClock on a bootable disk, insert that disk into the Mac Plus and boot it up. If you used the author’s disk image, you’ll see the icon for HappyPlusClock already in a window on the screen.

Before you start the clock software, now is a good time to make sure the system time is accurate. Mouse over to the Apple menu in the upper-left corner of the screen and select “Control Panel” from the pull-down menu.

In the General section of the Control Panel, set the system time, then close the window to save it.

Now double click the HappyPlusClock icon to start the software. Your screen should be taken over by a large digital clock with two icons in the lower left and right corners and a date line in the top center of the screen.

The icon on the lower left quits the program. The icon on the lower right toggles to analog clock face mode. If you click that, you’ll see this:

If you keep the mouse cursor still for a few seconds, the icon and the date line will disappear, leaving only the time or clock face. If you’d like to keep the date line on the screen, click the push pin icon next to the date line, and it will stay visible when the other icons fade out.

Sit back and enjoy

Now unplug the keyboard and mouse, sit back, relax, and enjoy. If the clock is in your bedroom, keep the brightness turned down at night time or it might keep you awake. If you want to keep it on in the long run, know that it will likely wear out your machine in at least two ways.

First, the phosphors in cathode ray tube (CRT) displays, like that in the Mac Plus, don’t last forever. They fade in intensity over time with use. That being so, HappyPlusClock has a neat feature to prevent uneven CRT burn-in. Every six hours, it inverts the colors of the clock face (from black-on-white to white-on-black and vice-versa) to even out the usage of the phosphors. Without this feature, your Mac Plus’s monitor would age unevenly, leaving visible burn-in of the most-used areas of the monitor if you left your new Macinclock running for a long period of time.

Here’s a photo of the software running in night mode:

Benj Edwards

Another thing to consider: If you keep the Mac Plus running in a hot place, it might stress the power supply to the point of breaking. Even without the additional heat, using an almost 30 year old computer running 24 hours a day is bound to expose flaws with your Mac Plus’ decaying electronic components (especially electrolytic capacitors, which go bad over time whether you use the machine or not). So if you see a small puff of smoke waft out of the top of your Mac Plus, it means a capacitor died on you and you’ll have to fix it (again, beyond the scope!).

Still, if you like Mac-themed novelty and have a spare Mac Plus that you don’t mind potentially ruining by accident, a Mac Plus clock makes an almost unbeatable conversation piece. Please let me know if you set one up!

Top photo provided by Benj Edwards.