- 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.
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.
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.
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.
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.
Ersterhernd
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.
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.
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.
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.
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.
Ersterhernd