How to Turn a High-Speed Gentle Typhoon Into a PWM Fan

Oh, so you bought a high-speed Gentle Typhoon. Was it the 3000 RPM AP-29, the 4250 RPM AP-30, or did you get really daring and go for an AP-31 5400 RPM “Gentle” Typhoon? I have an AP-30, and it’s not a quiet fan.

What if you want to control the speed of your high-speed Gentle Typhoon fan? Maybe you’re tired of it going full-blast all the time. It is quite noisy after all… What can you do? You could buy an expensive fan controller, but there is a better way. Actually, there are a couple of better ways, and they involve a hidden capability of your high-speed Gentle Typhoon’s PCB.

My attention was riveted when a user in another forum casually mentioned a PWM mod. What PWM mod? I asked. Oh, the one you can do on all the high-speed GT’s, he wrote. And I was off. I peeled back the label on my AP-30 and saw four daubs of solder in a row, and only three wires going to them. Excited now, I started warming up my trusty old soldering iron.

Then I found an unused fan wire and in no time I had my wire connected to the solder spot that had no wire. Now it does. Only then did I say to myself, You really ought to take some pictures here. Too late to do a step-by-step tutorial, but here is a shot of what the soldering accomplished:

The wire over on the right — the black one daubed with white paint — is the PWM line I added. I only had a black wire available, so I had to improvise.

Unfortunately, this won’t work with low-speed Gentle Typhoons, no PWM on the PCB.

Then I removed the other end of the yellow rpm wire from the three-wire plug and put that yellow rpm wire and the new PWM wire into a 4-wire PWM plug:

Now this fan can be controlled directly by the motherboard’s CPU fan PWM header. When the CPU idles, the fan is quiet. When the CPU loads up, the fan speeds up. You can also connect this fan and others with a 3-fan or 5-fan PWM Splitter.

Another way to control the fan is to hook it up to a Zalman PWM Mate (see my review), which controls any number of fans by PWM.

What You Need

1. A high-speed Gentle Typhoon
2. A soldering iron
3. An extra piece of wire
4. A female fan pin to crimp on the wire
5. A PWM plug

Where to Find What You Need

1. Various vendors carry the high-speed Gentle Typhoons.
2. You can get a 25 Watt or 40 Watt soldering iron at Radio Shack, Home Depot, or any number of places. Get one with as short a shank as you can. I found the Radio Shack irons to have their tips too far from the handle; they would be difficult to use.
3. The wire is 22 gauge. If you have a spool of it, you’re on your way, if you know how to crimp pins.
4. Female pins for fans can be found here, here, and here. You can get a crimp tool here. If you go this route, be sure to look at this tutorial. Be sure to buy lots of extras so you’ll feel free to learn how to do it. Another way to get an extra wire with a pin on it is to simply buy a plug with wires in it, and then use one of the wires. For example, here is a 3-wire fan tail. This particular item comes with a white wire, so it would be perfect for your PWM wire, since your other wires are black (ground), red (12 Volts) and yellow (tach). You can also buy an inexpensive 3-wire extension cable for fans (example). Simply cut the wire near the male end (the one with the points) and extract it from the female plug. NOTE: to extract a pin from a plug, push a small screwdriver into one of the slots and pull the wire out. Now you have a wire with a pin crimped to it.
5. Finally, you need a PWM plug. A diagram from Molex is here. I bought some from here, but those are expensive. I found a cheaper source here.

Now you’re ready!

What to Do

1. Find the unused solder spot. On the AP-30 it is the last in line. On the AP-29 it is one of the other spots.
2. Strip about 3 mm of insulation off the end of the wire.
3. Warm up your soldering iron.
4. Put the end of the wire on the unused solder spot.
5. Put the soldering iron on top of the wire. Leave it there. The idea is to make the wire so hot that the wire will heat the solder spot and melt its way in.
6. Lift the iron while holding the wire steady for a few seconds.
7. Give the wire a tug. If it stays on, good. If not, try again.
8. Inspect your work. Make sure there is no solder bridge to any other element on the PCB.
9. Now insert the wires into the PWM plug.

Look at the following pictures to see the correct places to put the wires:

Now if you want to really get fancy you can sleeve your cables. I want to show you what I did to mine because it clearly shows that one cable goes to the Molex for power, the other to the motherboard or a PWM controller for speed control:

Done.

– ehume