The Macintosh Plus was Apple’s third version on the all-in-one Mac, and for its time it was a veritable powerhouse. If you don’t have one here in 2025 there are a variety of ways to emulate it, but should you wish for something closer to the silicon there’s now [max1zzz]’s all-new Mac Plus motherboard in a mini-ITX form factor to look forward to.
As with other retrocomputing communities, the classic Mac world has seen quite a few projects replacing custom parts with modern equivalents. Thus it has reverse engineered Apple PALs, a replacement for the Sony sound chip, an ATtiny based take on the Mac real-time clock, and a Pi Pico that does VGA conversion. It’s all surface mount save for the connectors and the 68000, purely because a socketed processor allows for one of the gold-and-ceramic packages to be used. The memory is soldered, but with 4 megabytes, this is well-specced for a Mac Plus.
At the moment it’s still in the prototype spin phase, but plenty of work is being done and it shows meaningful progress towards an eventual release to the world. We are impressed, and look forward to the modern takes on a Mac Plus which will inevitably come from it. While you’re waiting, amuse yourself with a lower-spec take on an early Mac.
Thanks [DosFox] for the tip.
Sorry to be that guy but relying on a Pi Pico for VGA means it does rely on a special chip. It’s kind of a weird choice too because people have made VGA cards you can build.
or you could throw an FPGA at it. I’ve looked at using them to re-implement gate-for-gate a bunch of different custom apple chips.
Which in turn would mean you could do the whole thing inside said FPGA, but where is the beauty in that?
Besides, the Pico is an economic choice and not a bad one at that. Software is the new hardware. ;)
You could also not. Sure, I could put your entire desktop computer inside a single chip too, it’s called an SoC. Apple does it a lot these days.
But I could also say, “this is a gate-for-gate, pin-for-pin replica of an apple chip that actually exists.” Solder it to the same footprint on the board.
I think by “special chip” they mean some custom thing that’s been out of production for years that you’d have to gut a real Mac plus for.
It’s because it has to sample the Mac Plus’s 68K bus for video accesses and then convert them to VGA. So, a standard solution won’t work while the work done on getting a PICO to do that for a Mac Plus (and SE) so that you can connect these computers to VGA is established.
I was considering that when I needed to fix the blown flyback transformer on my Mac SE, but in the end I obtained a new flyback.
Care to define what you mean by a “standard solution”? Do you mean generating VGA using a microcontroller or something else?
People have built VGA “cards” from discrete logic chips, so it’s not like doing this with a Pi Pico is the only way.
I’m willing to cut max1zzz some slack on his VGA interface. Sure, elegance would increase by (eventually) deconstructing the RPi Pico daughter-board into a direct-soldered RP2040 chip, etc. but I don’t think incorporating a “VGA card” will make for a better story. Top “mad scientist” bragging rights are better garnered by adding a real CRT and high-voltage video section. (A good fraction of a MacPlus was its video cleverness). It still makes me smile to imagine my Mac Classic’s 512×342 pixel screen mapped onto a teeny, tiny corner of just one of the 2560×1440 LCDs in my home office.
No kidding.
Frankly unless it was all built entirely out of the most common 74 series logic chips or even using discrete transistors, I think you could argue that “special chips” are involved. Although it’s understandable that they would use a real Motorola MC68000 given the sheer difficulty of reimplementing that using discrete logic. And it’s silly to emulate it when a chip is available.
Perfection is the enemy of progress. It’s a working computer using a cheap off the shelf part to fix an issue. Any good engineer would see that
I’d love it if someone does a replacement SE/30 motherboard. Small machine but could have up to 128MB RAM and supported color video via 3rd party PDS adapter (or color VGA via Pi), built in SCSI with SD adapter, and ethernet support.
SE/30 reloaded exists.
The SE/30 should have been named the SEX, but Apple chickened out on the X naming convention for 68030 models up until that one..
Yep, Apple didn’t think ahead when they decided to give some Macintosh II line a ‘030 instead of ‘020. We got IIx, IIcx, and IIfx. Then SE came along and the upgraded SEx made them give up the idea.
Apple decided that elon musk was too cringe. (model S, Model 3, Model X, Model Y…)
YES PLEASE!
that’s a funky use for the pico. a total hack and seems to be a reminder that you can bitbang video with alacrity on a $4 chip these days!
There’s also a 1:1 reproduction of the Mac Plus board:
https://github.com/max234252/MacPlus-Reloaded
DosFox posted his progress getting the board to work on Mastodon:
https://appleinsider.com/articles/24/07/26/an-engineer-has-built-a-classic-mac-plus-from-modern-parts
Some of the parts for that board are a bit hard to find today. Amazingly, the components that are most difficult to find (at least here in Europe) are the angled 30-pin SIMM sockets…
The 1:1 repro is actually one of mine too (I have a different name on because someone had already pinched my usual name) It was my first RE project (as much as you can call it that) and I never expected it to really get any interest – and it didn’t really until last year when DosFox did the legwork to get a no original parts build working, Now I keep seeing them pop up all over the place!
Yep, I didn’t notice that right away, sorry… I have one of your 1:1 repro boards here, too – great work! I just have to find some time to finish the build and test it…
|the angled 30-pin SIMM sockets…
Even if you found some, odds are they are old stock with brittle plastic.
They were available (or at least still listed as) from a few connector manufacturers pre-covid but they’ve disappeared now, does give a bit of hope that the NOS ones might still be OK.
But, the last board I got with damaged 30 pin SIMM connectors I converted to use SIPPs by soldering on those double sided turned pin header/interconnects to the SIMMS and a strip of turned pin sockets, a bit of a twist on the old IC pin style ones.
still OS 1.0 or 7 is not open source
;(
Not other language, not bigest rom . Many people not needed big computer.
Another clickbait title…
It really isn’t