For all its friendly countenance and award-winning industrial design, there’s one thing the venerable Macintosh Plus can’t do: fit into a 1U rack space. OK, if we’re being honest with ourselves, there are a lot of things a Mac from 1986 can’t do, but the rack space is what [identity4] was focused on when they built the 2025 Rackintosh Plus.
For those of you already sharpening your pitchforks, worry not: [identity4]’s beloved vintage Mac was not disassembled for this project. This rack mount has instead become the home for a spare logic board they had acquired Why? They wanted to use a classic Mac in their studio, and for any more equipment to fit the space, it needed to go into the existing racks. It’s more practical than the motivation we see for a lot of hacks; it’s almost surprising it hasn’t happened before. (We’ve seen Mac Minis in racks, but not the classic hardware.)
Aside from the genuine Apple logic board, the thin rack also contains a BlueSCSI hard drive emulator, a Floppy Emu for SD-card floppy emulator, an RGB-to-HDMI converter to allow System 7 to shine on modern monitors, and of course a Mean Well power supply to keep everything running.The Floppy Emu required a little light surgery to move the screen so it would fit inside the low-profile rack. [identity4] also broke out the keyboard and mouse connectors to the front of the rack, but all other connectors stayed on the logic board at the rear.
Sound is handled by a single 8-ohm speaker that lives inside the rack mount, because even if the Rackintosh can now fit into a 1U space, it still can’t do stereo sound…or anything else a Macintosh Plus with 4 MB of RAM couldn’t do. Still, it’s a lovely hack. and the vintage-style advertisement was an excellent touch.
Now they just need the right monochrome display.
this is making me feel insecure about all of the different ‘piles of computers’ i’ve been responsible for over the years. i once made a desk out of two desktop pcs on their sides for the legs with one across them for the top.
Oh yah. If I think back about this…
But they were just junk at the time.
And if we all kept them all there would be no scarcity. They would still be junk.
But then the actual battery replacement kit says “1.2V AA rechargeable not supported”. It uses a 3.7 Volt lithium cell instead, or a single AA, with a boost regulator that’s going to eat up the battery when idle, so you have to recharge it every now and then. With the AA cell the regulator is mandatory. You can switch the regulator off, which means the battery voltage will eventually go down below specs and glitch the CMOS. And it costs 25 euros, plus the lithium cell.
Meanwhile, three alkaline AAs in a holder, or a 4.5 Volt lantern battery, would last basically forever and are dirt cheap. Why complicate things?
Better question, who came up with this product and why?
no. not the right question at all on this site…
brilliant idea! perfect for running Cubase and editors for ancient samplers and synths on one of my mac SE logic boards.
Not the computer, the battery replacement. This didn’t need to be a special product at all – just a battery holder and some batteries.
oh yeah. shure. did that back when batteries of my IIfx and 840av started dying on me. just a triple aa holder with velcro on a nice reachable spot. nothing to think about.
The whole project seems questionable, as you say, but I don’t think there’d be a problem with using a straight 3.7v lithium battery.
The mac plus uses the same pram/rtc chip as the subsequent 68k macs, which used a 3.3v primary lithium battery. The chip ran on 5v but its retention voltage, (and that of the similar CMOS chips that held bios settings on PCs of the era) was somewhere between 2-2.5v, so it should stay happy for nearly all of the usable life of a lithium battery.
As for why they used the 4.5v alkaline battery to begin with, my guess is cost and availability – I at least don’t recall the CR123 and CR2032 becoming ubiquitous until later in the 80’s.
One possible reason is, if the CMOS was powered two ways, from the system voltage and from the battery, you would have inserted a diode in series with the battery to prevent charging it. This simple OR-ing circuit would pick whichever was the highest voltage and run from that.
With a CR2032 or equivalent 3 Volt battery, if they were available, this would have subtracted enough voltage to make it too close when the battery runs down.
A 4.5 Volt alkaline battery goes down to about 3 Volts empty, which gives enough headroom. With a low-drain application like CMOS backup, the capacity of the battery – alkaline or lithium – is a secondary concern. The expiration date of the battery comes first.
Are we talking about the 3R12 lantern battery?
If so, yes, it’s a good and forgiving battery.
Even if shorted, it rarely catched fire.
It was Europe’s equivalent to the 9v E-block battery, I think.
It often was used in school and in electronic construction kits.
One battery was good enough to operate 5v TTL circuits, too.
And by adding two in series you got 9v just like with the 9v battery, too. Just way stronger.
The coal-zinc type of the 4,5v battery used to be very popular, though it dissolved eventually over time.
The Alkaline type is good, but I’m not sure if it’s still readily available due to manufacturing costs.
Applications for 4,5v batteries have become less, after all.
“Meanwhile, three alkaline AAs in a holder, or a 4.5 Volt lantern battery, would last basically forever and are dirt cheap. ”
In principle I wouldn’t disagree, but…
I like to maintain a small stock of batteries for all the electronic crap at my house–flashlights, TV remotes, DMMs, children’s toys, etc. I’m routinely disappointed to find new, unused, brand-name alkaline AAs, still in their package, leaking and/or dead. Date stamps say they should be good.
I had an expensive Maglight, (fully functional, casting a bright beam) that I tried to steal batteries out of to test something else. I unscrewed the cap and found perfectly “good” alkaline cells leaking, corroding, and swelling so much that not even a hammer and chisel could get them out.
Ad puffery notwithstanding, my experience is that the shelf-life of modern alkaline cells is abysmal, and the damage they do when they leak is even worse. I would NEVER rely on them for CMOS backup.
IMO, AA lithium (disulphide) primary cells would be the better choice for your proposed solution–they have roughly the same terminal voltage as alkalines, a MUCH longer shelf-life (as much as 10 years) , and at CMOS-backup current levels, a service life that would probably match shelf-life…. all with no threat of destructive leakage.
The battery holder is a separate piece off the main board, so even if a cell leaks it would only foul a $2 piece of plastic.
I second that. I have Alkaline AA batteries from the 1980s in my cupboard that are still in one piece, even have about 1,2v left.
Meanwhile, modern Alkaline batteries do usually leak within 5 years or so.
Not necessarily. The coin cells have a lower self-discharge than AAs.
A coin cell can last for 30 years, as battery-backed RAM in SNES/GB cartridges has proven.
In essence, it’s like this:
Coin cells=little current, but over a long time
Standard batteries=high current, but over a short time
When it comes to button cells, it’s good to make sure the contacts are clean (no finger prints).
A thin fat layer might add unwanted resistance etc.
Using isoprop alcohol and a q-tip helps at cleaning, for example.
A simple tissue may help, too.
Well, that’s another alternative. Either way, a rechargeable cell would have a shorter shelf-life and greater self-discharge than either option.
I adore rack-mount form factor. Just not the sound of 1U fans. But the Macintosh Plus has no cooling fans so this case works nicely.
And its kind of period-correct, even! 😃
Way back in the 1980s/1990s, musicians have put their Atari STs in 19″ rack chassis.
https://www.stcarchiv.de/tos1990/08/19-zoll-rack-umbauset-fuer-mega-st
shutuoandtakemymoney.jpg
That Mirror Universe ad is just Chef’s kiss
can i buy one? because ive always wanted rackmounted retro-computers