Customizing The Start-Up Chime On A 1999 G3 IMac

March 19, 2023 by Maya Posch 3 Comments

The start-up chime on Macs is probably as recognizable as the default Nokia ringtone in this day and age. Yet much like a ringtone, so too one might want to change the start-up chime on a Mac. This is something which [Doug Brown] has done in the past already on a Power Mac G3 in 2012, which made him instantly an expert on the topic in the eyes of a reader who wanted to know how to change the chime on a 1999 iMac. While the firmware on both these systems is written in Forth, it did take a bit of sleuthing to figure out where the chime was hiding in the firmware image, and how to change it.

The target iMac is somewhat unique in that it has a G4 PPC CPU rather than the more common G3. The firmware is similar enough that it was a snap to simply search the newer iMac’s firmware for the signature of the chime sound data. This turned out to be the identical QuickTime IMA ADPCM format-encoded data, yet what was different was how this data was integrated into the firmware image. Key is finding the area in the firmware where not only the address of the chime data’s start is defined, but also its length. Finally, the checksums in the firmware image have to be updated so that it matches the patched data.

Reverse-engineering the checksum calculation in the Forth code turned out to be fairly straightforward, but getting the new firmware on the iMac turned out to be the biggest struggle, as [Doug] didn’t want to inflict running a manual firmware update onto this reader he was doing all this work for. This led [Doug] to do some more reverse-engineering using Ghidra to enable the use of the automatic updater like a regular firmware update.

In the end it all worked out great, and now another iMac no longer has the Mac chime on start-up.

MorphOS: A Modern Operating System For PowerPC

February 27, 2023 by Maya Posch 28 Comments

When it comes to modern operating systems for PowerPC-based systems like pre-Intel Macs, or other PowerPC-based systems like older or newer AmigaOS-compatible systems, there is an increasing lack of options. For 32-bit PPC, official Linux support has been dropped already, leaving only unofficial builds and of course AmigaOS as well as AmigaOS-like operating systems. So what do you do if you have a PPC-based Mac system lying around which you do not simply want to run the same old, unsupported copy of MacOS on? In a recent video, [Michael MJD] decided to give MorphOS 3.17 a shot on a Mac G4 Cube.

Originally created for the now-defunct Pegasos PPC-based series of computers and PPC accelerator cards for Amiga systems, MorphOS is based on the proprietary Quark microkernel, In its current release, it supports a range of G4 and G5-based Apple systems, as well as the AmigaOne 500 and X5000, with some asterisks. In addition to its own applications it supports AmigaOS applications, including those targeting the m68k architecture, via its JIT emulator.

A cursory look at the community shows that MorphOS finds use for being a fast and relatively up to date alternative OS for especially PPC-based Macs. The price tag of €79 per system (transferable to a new system) should offer some guarantee of continued development, which includes e.g. the Wayfarer browser for MorphOS, which is based on Webkit, but optimized for e.g. Altivec.

Although installing MorphOS went relatively smoothly for [Michael] (with just a monitor-related glitch), he did not try too much beyond an initial impression of the GUI and preinstalled applications. There is also a 30-minute timer on the trial version (resettable via reboot) that ended [Michael]’s look at this OS.

What do you run on your PPC-based machines, and have you used MorphOS? What are your thoughts on this OS?

Continue reading “MorphOS: A Modern Operating System For PowerPC” →

Swap The Clock Chip On The Mac SE/30 With An ATTiny85

January 13, 2023 by Tom Nardi 20 Comments

As [Phil Greenland] explains in the first part of his excellent write-up, the lithium battery used to keep the real-time clock (RTC) going on the Macintosh SE/30 has a nasty habit of exploding and leaking its corrosive innards all over the board. Looking to both repair the damage on a system that’s already had a battery popped and avoid the issue altogether on pristine boards, he started researching how he could replace the battery with something a bit more modern.

It turns out, the ATtiny85 is pin-compatible with the Mac’s original RTC chip, and indeed, [Andrew Makousky] had already written some code that would allow the microcontroller to emulate it. This is actually a bit more complex than you might realize, as the original RTC chip was doing double-duty: it also held 256 bytes of parameter random access memory (PRAM), which is where the machine stored assorted bits of info like which drive to boot from and the mouse cursor speed.

But after getting the mod installed, the computer refused to start. It turns out the project targeted earlier machines like the Macintosh Plus and SE, and not his higher-performance SE/30. Thanks to community resources like this KiCad recreation of the SE/30’s motherboard, contemporary technical documents, and his trusty logic analyzer, [Phil] was able to figure out that the timing was off — the code was simply struggling to respond to the faster machine. Continue reading “Swap The Clock Chip On The Mac SE/30 With An ATTiny85” →

A beige keyboard with blue and grey keys sits on a colorful deskmat atop a wooden desk. A small box with a round Touch ID button sits next to the keyboard.

Standalone Touch ID For Your Desktop Mac

December 26, 2022 by Navarre Bartz 1 Comment

With the proliferation of biometric access to mobile devices, entering a password on your desktop can feel so passé. [Snazzy Labs] decided to fix this problem for his Mac by liberating the Touch ID from a new Apple keyboard.

When Apple introduced its own silicon for its desktops, it also revealed desktop keyboards that included their Touch ID fingerprint reader system. Fingerprint access to your computer is handy, but not everyone is a fan of the typing experience on Apple keyboards. Wanting to avoid taping a keyboard under his desk, [Snazzy Labs] pulled the logic board from the keyboard and designed a new 3D printed enclosure for the Touch ID button and logic board so that the fingerprint reader could reside close to where the users hands actually are.

One interesting detail discovered was the significantly different logic boards between the standard and numpad-containing variants. The final enclosure designs feature both wireless and wired versions for both the standard and numpad logic boards if you should choose to build one of your own. We’re interested to see if someone can take this the next step and use the logic board to wire up a custom mechanical keyboard with Touch ID.

If [Snazzy Labs] seems familiar, you may recognize him from their Mac Mini Mini. If you’re more in the mood to take your security to the extreme, check out this Four Factor Biometric Lockbox that includes its own fingerprint reader.

Continue reading “Standalone Touch ID For Your Desktop Mac” →

The bottom half of a MacBook Air on a purple and pink background has severed wires drawn out of its back to indicate its lack of a screen.

Are Slabtops The Future Of Computing?

November 25, 2022 by Navarre Bartz 114 Comments

The most popular computer ever was the Commodore 64 with its computer-in-a-keyboard form factor. If you have a longing for a keyboard computer with more modern internals, one of the easiest solutions today is to pull the screen off a laptop.

[Umar Shakir] wanted to see what the fuss was about regarding a recent Apple patent and took the top lid off of his M1 Macbook Air and turned it into a “slabtop.” The computer works great wired to a monitor but can also be used wirelessly via AirPlay. The approach doesn’t come without its downsides, of course. Newer MacBooks can’t access recovery mode without the built-in screen, and some older models had their WiFi antennas in the top lid, so making one into a slabtop will leave you desk-bound.

While [Shakir] focuses on MacBooks, this approach should work with any laptop. Apparently, it’s a cottage industry in China already. Back in the day, my own daily driver was a Pentium-powered laptop with its broken LCD (and lid) removed. It worked great with whatever CRT was nearby.

If you’re looking for an off-the-shelf keyboard computer of your own, you might want to check out the Raspberry Pi 400.

This Wii Has An Apple M1 Inside

November 9, 2022 by Navarre Bartz 8 Comments

The conveniently tiny logic board of the M1 Mac mini has lead to it giving the Mini ITX format a run for its money in case mods. The latest example of this is [Luke Miani]’s M1 Wii. (Youtube via 9to5Mac)

[Miani] chose the Wii as a new enclosure for this Mac mini given its similar form factor and the convenient set of doors in the top to maintain access to the computer’s I/O, something he wasn’t able to do with one of his previous M1 casemods. The completed build is a great stealth way to have a Mac mini in your entertainment center. [Miani] even spends the last several minutes of the video showing the M1 Wii running Wii, GameCube, and PS2 games to really bring it full circle.

A Microsoft Surface power brick was spliced into the original Wii power cable since the Wii PSU didn’t have enough wattage to supply the Mac mini without significant throttling. On the inside, the power runs through a buck converter before making its way to the logic board. While the Mini’s original fan was too big to fit inside the Wii enclosure, a small 12V fan was able to keep performance similar to OEM and much higher than running the M1 fanless without a heat spreader.

If you’d like to see some more M1 casemods, check out this Lampshade iMac or the Mac Mini Mini.

Continue reading “This Wii Has An Apple M1 Inside” →

Mac 128K Emulator Gets DIY Ceramic Enclosure

October 6, 2022 by Lee Wilkins 8 Comments

Creative technologist [Joselyn McDonald] wanted to hone her ceramic skills by building an iconic Macintosh 128K sculpture, complete with a fully functional operating system.

At first, she was determined to use Processing to create an interface for her sculpture by recreating the UI visually and adding some touch controls. However, she soon abandoned this tedious task after discovering MacintoshPi, which steps you through installing Mac OS 7, 8, and 9 emulators on a Raspberry Pi. [Joselyn] has also installed several retro games, including DOOM II, Carmen Sandiego, and Sim City, thanks to sites like Macintosh Garden and Macintosh Repository.

Next, [Joselyn] hopes to set it up to display her and her partner’s schedules, and to let friends play around with nostalgic games. This piece was made using hand building, but other cool ceramic techniques like this slip cast dog bowl and this stone 3D printer have us thinking about what other types of enclosures could be built!