Simple PSU Fan Swap Technique

Fans|Controls | Power

May 17, 2003 by Mike Chin

A common mod done by many SPCR readers is to swap out noisy fans in power supplies with quieter ones. There is always a risk of PSU overheating and resulting in early failure, but as questions about this procedure come up constantly, here is a simple pictorial of the most common scenario.

Note that ALL risks are yours; we're not saying you should do this, and if you choose to do so, you are responsible for taking all necessary precautions such as unplugging the PSU from AC power, and ensuring protection from high voltage capacitor discharge!

This article describes one simple way to deal with the special pin connectors for fan voltage often found in power supplies.

Many PSU fans get their driving DC voltage from the PSU printed circuit board via a small 2-pin connector. One lead is invariably red for the +(plus) voltage and the other, usually black or blue, carries the -(minus) voltage. Note that this -(minus) voltage is available from ANY black wire in the PSU; they are all joined together to a "common ground".

The picture on below shows the interior of a Seasonic PSU. The black object visible on the right is the 80mm fan.

Note the polarity / color of the wires. The picture below show the connector from the fan removed.

Most 80mm case or heatsink fans do not have a connector that will fit this 2-pin connector. But there is a simple solution. Simply remove the whole plastic/nylon piece that surrounds the 2 pins, and many different types of female connectors from fans will fit.

A small screwdriver starts the process. You can also emply a small pair of needle nose pliers to grip and pull the plastic/nylon piece off. It is only press-fitted in, and held by friction. Ease it out slowly and carefully. If it sticks badly and doesn't want to come, don't force it because the pin can actually be pulled from the PCB; I write from experience. :p You can use a hair dryer on the hot setting and blow it for 30~60 seconds directly at the plastic piece to soften it so it slips off the pins more easily.

Here's how it looks with the plastic/nylon piece off.

Now you can plug in the 2-pin connector found on many Panaflo 80mm L fans. Standard 3-pin plugs for motherboard headers also fit fine -- just get the polarity right, and use the red and black/blue wires as mentioned before. A small amount to pressure to spread the pins is perfectly OK. There is usually more than enough tension in the connector to keep it secure on the pins even without the locking action of the plastic sleeve.

Simple enough for you?

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