As mentioned, you can remove the lower hard disk drive cage to install a 120 mm fan, if you want to add the maximum amount of fans you can. In this case you will lose three hard disk drive bays. Interesting enough this option is not documented by Zalman, probably due to the difficulty on installing this optional fan.

This process is far from being easy, as you will need to remove the front and top panels. Because of that, we wrote this tutorial explaining how to remove the lower hard disk drive cage.

• 1. Remove all hard disk drive drawers from the lower hard disk drive cage.
• 2. Remove all covers and adapters from the 5 ¼” bays.
• 3. On the rear part of the case, remove the two screws that fasten the top panel to the case (Figure 20).

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Figure 20: Remove these two screws located on the rear part of the case.

• 4. Find a screw located inside the case on the front top part (Figure 21). There is one on each side of the case. Remove them.

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Figure 21: Remove this screw (the case is upside down on this picture).

• 5. Remove the top panel from the case. With this panel removed, find the screws that fasten the front panel to the top part of the case and remove them (Figure 22).

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Figure 22: Remove these screws.

• 6. Remove the screws that fasten the front panel to the bottom part of the case and remove them (Figure 23).

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Figure 23: Remove these screws located on the bottom panel from the case.

• 7. Now press the latches that hold the front panel to the case and remove the front panel.

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Figure 24: Press this latch. There are eight of them (four on each side).

• 8. On the lower hard disk drive cage, remove the two plastic panels that hold the hard disk drive drawers to the case.
• 9. Phew! You will have now access to the place for installing the 120 mm fan. Install it.

 
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Figure 25: Place for installing the 120 mm fan.

• 10. Put everything back in place, except the plastic panels from the hard disk drive cage, because they won’t fit the case with the fan installed.