Contribute
Register

Ersterhernds iMac G5 20 Inch A1076 Project

Status
Not open for further replies.
Joined
Nov 25, 2010
Messages
1,211
Motherboard
AsRock X570M Pro4
CPU
Ryzen 3700x
Graphics
RX 580
Build Log 06 - Cooling Fans

There are three fans in this iMac. By design, the top two fans expel air from the top rear slot of the case, while the bottom assembly uses a tiny fan that draws air in from underneath. I think the bottom fan is a 40mm unit. All are pictured below.


applefansG5.jpg


bottomfan.jpg




They all share a common style of connector that uses 4 wires. Since the tach function isn't necessary in this build, only three of the connecting wires per fan were used. The iMac G5 Fan Pinout diagram used in this build is shown below.

iMacG5fanPinout.png




All three original fan connectors were glued together into a single block, then the three wires from each fan were spliced from 9 into 3 for connection to the ATX power supply.

ciHcpi.png



The bottom fan assembly housing (BookYard photo shown above) took up space that was needed for the Intel NUC, so I extracted the 40mm fan out of it and mounted it directly beside the Intel NUC D54250WYK. It draws a small amout of fresh air directly onto the NUC through the vent holes in the bottom of the iMac case. It runs at 3.3V with the others, and is completely silent.

mWYJR2.png




The result is fantastic. The screenshot below shows the temps of this system after an hour of use (note that the CPU Heatsink reading is wrong). Using 3.3V for the fans is very quiet and moves plenty of air. I tried 5V but the result was more noise and no improvement in temps, so put it back to 3.3V where it will stay.

QZU0p6.png




Ersterhernd
 
Joined
Sep 6, 2014
Messages
34
Motherboard
Intel NUC D54250WYK
CPU
i5-4250
Graphics
HD5000
Mac
Classic Mac
Mobile Phone
  1. Android
The 40mm fan at the bottom is an intake fan I believe. Things are designed to help convection along.

:thumbup:
 
Joined
Nov 25, 2010
Messages
1,211
Motherboard
AsRock X570M Pro4
CPU
Ryzen 3700x
Graphics
RX 580
Build Log 07 - Intel NUC 65W Power Supply

Usage of the supplied 65W NUC PSU was done in this build for three reasons...

1. To keep the Intel NUC in standby mode and power it during use
2. To reduce load on the Apple G5 PSU for absolute minimum stress on it
3. There was space available to use it and it fit perfectly


Three tasks needed to be completed for using the NUC PSU.

1. Install a 4" long mounting/spacer bar attached to the iMac midplane
2. Cut the AC cord to length and splice to AC inside the Apple PSU
3. Cut the 19V output cord to length and re-splice together


The result worked great. The NUC PSU just barely fits, the iMac rear cover actually touches it when the system is closed up. With no impact on the aesthetics and full compatibility with powering the NUC, I'm convinced this was a great way to put this PSU to work.


NUCPSU.png




Typical power draw with LCD brightness about 1/2 way up is around 40W out of the mains. I'm not certain how much draw is handled by the NUC PSU, but guessing around 12 to 15W. This puts the typical stress load on the Apple 180W PSU into the sub 30W range. I'm hopeful that it lasts a long time with such little load.


IMG_0742.JPG




Ersterhernd
 
Joined
Nov 25, 2010
Messages
1,211
Motherboard
AsRock X570M Pro4
CPU
Ryzen 3700x
Graphics
RX 580
The 40mm fan at the bottom is an intake fan I believe. Things are designed to help convection along.

:thumbup:


Yes, you're right buurin! I'll fix it in the post... thx.
 
Joined
Nov 25, 2010
Messages
1,211
Motherboard
AsRock X570M Pro4
CPU
Ryzen 3700x
Graphics
RX 580
Build Log 08 - USB Connections

This system uses all 6 available USB ports on the NUC D54250WYK as follows...

- 3 x USB 2.0 exterior iMac ports
- 1 x Startech ICUSBAUDIOB sound device
- 1 x Apple A1181 Bluetooth (5V not used as this is a 3.3V device)
- 1 x 5V & GND only to power LED/Chime Controller

I chose not to implement USB 3.0 into this build, at least not yet. It would have required the addition of a USB Hub, and in all honesty I really have never found a compelling use for USB 3.0 functions over the 2.0 standard.

Rather than purchase and install a hub, I simply mounted a piece of 3mm perspex to the back of the LCD panel and fastened everything to that with 3M sticky pads. Easy and effective. Note that I removed most shielding from the USB cables as it took too much space inside the iMac. No issue with that as of yet.


aVMW5l.png




Ersterhernd
 
Joined
Sep 6, 2014
Messages
34
Motherboard
Intel NUC D54250WYK
CPU
i5-4250
Graphics
HD5000
Mac
Classic Mac
Mobile Phone
  1. Android
I think I'll be watching this space more closely now, since my plans for modding a 15" G4 into a 20" G4 seems to be going to a dead end, and I do have a mostly intact G5 shell devoid of much mounting hardware. :lol:

However, I am determined to not let my G4 hardware go to waste. can the 2-part G4 power supply be crammed inside, paired with a pico driving the rest? Or I'll need to cram a 240W TFX supply inside, and find my own 24V solution (ie. 3 power supplies... ugly:sick:)
 
Joined
Nov 25, 2010
Messages
1,211
Motherboard
AsRock X570M Pro4
CPU
Ryzen 3700x
Graphics
RX 580
Build Log 09 - Apple Startup Chime

EDIT: A more authentic sounding Apple Chime in this build is detailed in this post.

The startup chime (or 'bong' as some people call it) is a nice touch for a G5 build. I haven't yet figured a way to play it over the system internal speakers as the original iMac did and don't know if its even possible, but a basic mono playback setup works good too.

The setup is simple, it uses a Picaxe microcontroller that simply sends a single high output to the Playe pin of an Arduino ISD1820 sound recorder. This ISD1820 has a recorded chime sound in its memory which plays once and only once at startup. The speaker used is from an iMac G4.



Arduino ISD1820 and Apple G4 Speaker

MJk7IN.png




iMac A1076 Startup Video with Chime

[video=youtube;CyXzjWAAi-Q]https://www.youtube.com/watch?v=CyXzjWAAi-Q&list=UUKec_H3wAJbsvZsYh6aGObw[/video]



For complete details of see this link.



Ersterhernd
 
Joined
Sep 6, 2014
Messages
34
Motherboard
Intel NUC D54250WYK
CPU
i5-4250
Graphics
HD5000
Mac
Classic Mac
Mobile Phone
  1. Android
Build Log 09 - Apple Startup Chime

The startup chime (or 'bong' as some people call it) is a nice touch for a G5 build. I haven't yet figured a way to play it over the system internal speakers as the original iMac did and don't know if its even possible, but a basic mono playback setup works good too.

The setup is simple, it uses a Picaxe microcontroller that simply sends a single high output to the Playe pin of an Arduino ISD1820 sound recorder. This ISD1820 has a recorded chime sound in its memory which plays once and only once at startup. The speaker used is from an iMac G4.
I still think it is a shame that NUC's firmware has the built-in option to play a startup sound, but we have no way to change what gets played (the Intel jingle).
 
Joined
Nov 25, 2010
Messages
1,211
Motherboard
AsRock X570M Pro4
CPU
Ryzen 3700x
Graphics
RX 580
Build Log 10 - iMac Rear USB Ports

The only functionality required from the iMac rear I/O in this build was 3 x USB 2.0 ports. I considered USB 3.0 and Ethernet, but at this point decided to shelve those ideas because I really don't need them.

That said, external USB 2.0 connectivity is critical to the iMac build. Due to the all-in-one style of the system, the rear ports must be kept intact for plugging in external devices.

There are 2 ways to accomplish the rear USB port functionality. The first requires isolating the existing ports and soldering wires directly to the USB port traces on the rear of the iMac logic board. I successfully accomplished this on my previous iMac builds. It was fussy work as the soldering is tedious.


Method One : Soldered USB traces (not used here but shown from previous iMac G5 project)

IMG_4982.JPG




A second method is possible for USB port installation on the A1076 model of iMac G5. The computer has a plastic housing that holds all components of the rear I/O panel. This housing makes it fairly easy to simply replace the original iMac USB 2.0 ports with new ones. That is what I did in this project. Credit goes to Kiwi for the idea of this repurposed port implementation.


Method Two : In this build the old ports were cut out with a dremel and new ones installed

IMG_0748.JPG


IMG_0749.JPG



Three new female USB cable housings were trimmed to match the extruding plug length of the originals. The wire end was cut away because there is only a few millimeters of clearance underneath the iMac logic board to route the wires. The wires from the USB ports needed to fit, so removal of all cable shielding was also necessary.


Three female USB cable ends needed to be trimmed as shown below

IMG_0747.JPG




The three trimmed female USB plugs were then glued into the iMac rear I/O housing using JB Kwik Weld. The depth of the plugs was critical so as to match up precisely with the rear outer shell of the iMac case.



The new USB ports are gold in color

IMG_0665.JPG



Rear view of iMac logic board with JB Kwik Welded USB cables

IMG_0666.JPG



Perfectly positioned USB 2.0 ports with iMac rear cover installed

IMG_0731.JPG



The completed USB port conversion works perfectly. Devices are instantly recognized when inserted and there is no issue with data transfer whatsoever. The ports are mounted very securely with JB Weld and will easily withstand any external force of plugging or unplugging a device.



Ersterhernd
 
Joined
Nov 25, 2010
Messages
1,211
Motherboard
AsRock X570M Pro4
CPU
Ryzen 3700x
Graphics
RX 580
I still think it is a shame that NUC's firmware has the built-in option to play a startup sound, but we have no way to change what gets played (the Intel jingle).


Pathetic yes. I wonder if Intel would respond to an email with an attached Apple Chime mp3 ? :think:


Cheers!
 
Status
Not open for further replies.
Top