How to Hackintosh Your IMac G4

by TheDIYGuy999 in Circuits > Apple

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How to Hackintosh Your IMac G4

iMac G4 Hackintosh "HemiMac" build - tight!
iMac G4 and G5 Hackintoshs running macOS Sierra

You have a nice looking iMac G4? And you just can't throw it away?

Then this instructable is the solution for you. But be warned: you need a lot of patience and good electronics knowledge...

The problem is, that this thing is about 15 years old now. Apple discontinued the PowerPC architecture about 10 years ago and there are no updates available anymore. So you can't really use it anymore. Even playing a YouTube video is beyond the capability of the PowerPC G4 CPU

Those are the specifications of the renewed iMac:

  • Original Super Drive
  • Original 17" screen
  • Original M6531 Pro Speakers with proprietary 2.5mm plug
  • Apple Chime startup sound
  • PAM8403 amplifier for speakers
  • INTEL i5 NUC DC54327HYE
  • Bluetooth
  • WiFi
  • Gigabit LAN, using the original socket
  • Internal PSU (NUC PSU and Pico PSU for 12V, 5V, 3.3V)
  • Picaxe controlled PSU, Apple Chime, PWM system fan, "breathing" sleep LED
  • Separate Picaxe controller for screen backlights control via touch sensors

Also have a look at my other Hackintosh videos: https://www.youtube.com/playlist?list=PLGO5EJJClJ...

Inverter Reverse Engineering and Disassembly

iMac G4 LCD measuring 1.jpg
iMac G4 original inside.jpg
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First, we need to know how the inverter pinout is. This requires to measure the signals on the living object. The next thing to do is to remove all the old innards.

Dome Modification

iMac G4 Faraday Cage removed.jpg
iMac G4 drilling Faraday Cage.jpg
iMac G4 deburr Faraday Cage.jpg
iMac G4 Drilled Faraday Cage.jpg

The touch sensors for the CCFL brightness adjustment require two big holes in the faraday cage.

WiFi Antenna Replacement

iMac G4 old WiFi 2.jpg
iMac G4 old WiFi.jpg
iMac G4 new WiFi antenna.jpg
iMac G4 new WiFi 1.jpg
iMac G4 new WiFi 2.jpg
iMac G4 new WiFi inside.jpg

The original WiFi antenna needs to be replaced with a new one from Tyco

LCD Wiring

iMac G4 finished DVI adapter.jpg
iMac G4 GND wiring.jpg
iMac G4 Hot Plug wiring.jpg
iMac G4 Inverter wired 1.jpg
iMac G4 _first _sreen.jpg

The custom Apple LCD connector needs to be replaced with a HDMI connector. The pinout can be found on Dremeljunkies web site: http://www.dremeljunkie.com/2011/08/guide-step-by...

Power Supply

iMac G4 PSU start test 2.jpg
iMac G4 PicoPSU 1.jpg
iMac G4 PicoPSU 2.jpg
iMac G4 Sleep Controller pre-assembled.jpg
iMac G4 Sleep controller.jpg
iMac G4 power socket 1.jpg
iMac G4 power socket 2.jpg
iMac G4 power socket 3.jpg
iMac G4 power socket 4.jpg

The 19V NUC PSU powers the entire system. An additional Pico PSU converts the 19V input voltage to 12V, 5V and 3.3V for the screen, the optical drive etc. It is switched on and off, using a custom made controller.

Warning!

Working with mains voltage is dangerous can cause serious injury or even d..th! Be careful! The most important point is, that the metal part of the dome is always properly connected with the ground wire!!

CCFL Backlight Brightness Controller

iMac G4 Touch Pad Test.jpg
iMac G4 Touch Sensor Rework1.jpg
iMac G4 Touch Sensor Rework2.jpg
iMac G4 Touch Sensors installed.jpg

The backlights are controlled from a Picaxe microcontroller and two touch sensors. This little extra makes a brightness change very convenient.

NUC Installation

iMac G4 NUC placement.jpg
iMac G4 NUC pre-mounted.jpg
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The Intel NUC is installed in the top half of the dome, below the new 80mm Noctua fan. This leaves just enough room for the original Super Drive.

Super Drive Installation

iMac G4 DVD mod 1.jpg
iMac G4 DVD mod 2.jpg
iMac G4 DVD mounted.jpg

The original Super Drive is connected, using an ATA to USB adapter. A little cutout in the sheet metal housing is required in order to free some space for the internal NUC power connector. All the custom electronics and the Chime controller are mounted on the bottom side of the drive housing.

Apple Chime

iMac G4 Chime 1.jpg
iMac G4 Chime 2.jpg
iMac G4 DVD bottom.jpg

A vintage Apple computer just needs an "Apple Chime" start sound. A new sound module drives the original internal speaker and is controlled by the Picaxe controller, which is described in step 5.

Speakers

iMac G4 Pro Speakers 4.jpg
iMac G4 Pro Speakers 3.jpg
iMac G4 Pro Speakers 1.jpg
iMac G4 AMP Rework1.jpg

The original M6531 Pro Speakers are used in original condition, using their 2.5mm Apple connector. The signal comes from a USB sound adapter and is then amplified in a PAM8403 class D amplifier. The original 2.5mm socket on the mainboard is rewired.

PWM Fan Controller

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iMac G4 Fan Controller 4.jpg
iMac G4 finished electronics.jpg

To keep the fan noise as silent as possible, a temperature controlled Picaxe fan controller is implemented in this step.

USB and Ethernet Wiring

iMac G4 finalized connectors.jpg
iMac G4 finalized botom wiring.jpg
iMac G4 glueing USB ports.jpg
iMac G4 Network rewired.jpg

In this step, the original USB sockets are removed and replaced with new ones. The two FireWire sockets are replaced with a USB 3.0 socket. In addition, the original Ethernet socket is rewired and reused. The original power switch is also reused and rewired.

NUC CMOS Battery

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The NUC CMOS battery is moved outside the NUC, in order to keep it accessible.

Final Assembly and Conclusion

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That's it!

Most of the custom electronics are accessible through the original maintenance opening in the bottom

Some more details can be found here: https://www.tonymacx86.com/threads/mactester57s-h...

Conclusion: This mod turned out well and works just fine. But it was A LOT of work. Today, I would do several things different. For example, I would use an Arduino Microcontroller instead of the three! Picaxes. I already did that in my iMac G5 conversion:

If you like this Instructable, please subscribe to my YouTube channel: https://www.youtube.com/channel/UCqWO3PNCSjHmYiAC...

See you!