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o2sys

macrumors member
Original poster
Dec 2, 2011
52
0
NYC
I cant seem to understand how the Zalman Quiet Fan is going to be quieter than the original fan?

Take a look, looks identical:
IMG-20111214-00198.jpg


The Zalman does come with this RC56 resistor cable for silent mode? whatever that means...will this silent mode be compatible with the imac?

I want to make sure because I dont want to reopen this thing.

UPDATE:

Silicone mounts for the fan bracket:
IMG-20111220-00211.jpg


All bolted up, with quick splice and connect of the fan wire because the apple plug coming from the logicboard is female. Also the Zalman fan controller works! At the lowest setting its ultra quiet and yet blows a lot of air
IMG-20111220-00212.jpg
 
Last edited:
Most fans of a given size will "look" identical.....the noise factor is mostly due to the bearings used for the fan spindle. Better bearings mean smoother rotation meaning quieter operation at the same RPM.
 
There is also what should be the obvious fact that the iMac fan is several years old. Most Macs outlive their fans. Normally a good fan will only perform at 100% quality of it's ability for 3-5 years. You're better off with the new one.

You can open an iMac on your own so it shouldn't be a stretch to imagine how a new fan is better for your iMac.
 
I tested it out at the new fan is WAY too loud as it seems the imac doesnt have some type of fan controller or temp sensor it just spins the new fan and full 12V making it WAY noisier than the white original fan.

Going to put a Zalman fan controller that I have to see if it works with the imac.
 
You see on the white fan has yellow, red, and black? But from the Imac mobo, only red/black connect and the yellow is empty.

What is the yellow for?
 
Yellow is to sense the speed of the fan. When the iMac knows the fan's speed, it can adjust the voltage accordingly to its heat output. With no idea how fast the fan is going, the iMac goes into a fail safe mode and put all power to the fan.
 
Yellow is to sense the speed of the fan. When the iMac knows the fan's speed, it can adjust the voltage accordingly to its heat output. With no idea how fast the fan is going, the iMac goes into a fail safe mode and put all power to the fan.

Ok, but I'm telling you the connector coming from the iMac's logic board does not have the yellow wire, only red/black. So the yellow wire goes into an empty slot.
 
I told you what the yellow wire does. Its possible that the new fan and the old have different power requirements.
 
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