Changing the exhaust fan on Enermax PSU

PSUs: The source of DC power for all components in the PC & often a big noise source.

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MrMajestic
Posts: 121
Joined: Sun Aug 11, 2002 3:26 pm
Location: Sweden

Post by MrMajestic » Mon Aug 12, 2002 2:32 pm

I am currently trying to change the exhaust fan on an Enermax PSU. Im going to put in an Enermax adjustable fan instead. The problem is that there is apparently some kind of temp monitoring going on giving me very low voltage to the fan. There is a temp sensor stuck to a coil inside of the PSU so I guess thats the one responsible for the low voltage. Can I snip that sucker off and replace it with a resistor? Or would it be easier to just run the fan from a regular powerplug outside of the PSU? And also, does the sensor control both fans or just the exhaust fan? The 92mm fan does seem to move very slowly to. There is also a plug for the motherboard but that was connected to the fan I removed. I am running the PSU outside of a case without load while modding it, so there is no load.
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MikeC
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Post by MikeC » Mon Aug 12, 2002 2:32 pm

Not all Enermax models work the same way, but it sounds like you have one like the first one I got. The 92mm fan spun relatively slowly (but still may have been at 12V, can't remember) & was unaffected by the thermistor. The 80mm fan was controlled by the thermistor.
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<br>Why worry about the thermistor at all? Just plop your fan in. If it doesn't spin, turn the manual speed knob up till it does. See what happens over time. If the thermistor heating up causes the fan to go too loud/fast, at that point, go to full manual control by replacing the thermistor with any restance between 0 and 100,000 ohms. 0 ohms should give you 12V at the 80mm fan output, 100,000 ohms will give you 5V.
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<br>A simpler thing (maybe cheaper) is to replace the fan with a Panaflo or similar quiet fan, then replace the thermistor with any 100K ohm pot. HINT: the thermistor IS a potentiometer, it's just not directly controlled by an adjustable knob; instead it is controlled by temperature. See the postscript added to the PSU mod article.
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MrMajestic
Posts: 121
Joined: Sun Aug 11, 2002 3:26 pm
Location: Sweden

Post by MrMajestic » Mon Aug 12, 2002 2:32 pm

Thanks for the reply. At the moment the Enermax fan is powered from outside of the PSU to ensure that it always spins. I will change the thermistor with a 100k pot later and probably take out the Enermax fan and put in a Zalman instead. Zalmans are cheaper than Enermax and Panaflos arent readily available here in Sweden.
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