Mac IIsi project: fan questions

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Joined: Dec 11 2006
Posts: 34


I have accumulated some upgrades for my IIsi that include:

  • SuperMac Video Spigot Pro video card
  • Asante ethernet card (si/se30 version)
  • Daystar Turbo 040
  • Daystar SE/30 adapter to hold the Turbo 040

I have all of these cards installed using some of the connectors mentioned in this thread. In order to fit everything in I needed to remove the stock fan as one of the cards need to occupy some of the space where the fan sits (I’ll add a photo when I am at home). The system runs great with the case top off however with the case top on, the 040 gets too hot and the system hangs. To fix the problem I purchased an extra si fan + fan case and removed some of the grill from the fan case. What I need to do next is replace the stock 60X60X25mm fan with one that is only 20mm in depth, then everything will fit.

This is the info on the stock fan:

  • DC Pico Ace 25
  • model 09R06 2M404
  • DC 12V 0.06a

I googled a bit and found this helpful spec sheet:

Model number 109R0612M402(4021) (listed under 25mm thick) seems to be a close match to the stock si fan both in dimensions and amps (0.06a). When I look at the lowest amp 20mm version of this fan (model 109R0612M602), it moves less air than then 25mm version -- 12.7 CFM vs. 10.6 -- and is rated at 0.09a. Moving one model up in the 20mm size (109R0612H602), it moves 14.8 CFM and is rated at 1.3a.

I am not an EE so have a few questions:

  1. Does anyone know what the CFM is for the stock si fan? I am thinking that I need to move at least the same amount of air if not more.
  2. If I were to get the 14.8 CFM/1.3a 20mm fan, will I run into issues with the stock si power supply?
  3. I have seen the correct size fans available with various connectors including bare wire and an inline 4-wire connector that would fit in front of the hard drive, but none with the tabs that the 2-wire stock fan has. Would there be any issue using the inline connector that would fit in front of the hard drive? If not, that would keep me from cutting and soldering the fittings from the stock fan to the new fan.

Any input on the above questions or other insight is appreciated!