Silencing some old (but good) PSUs

[fattypants]

The PSU in my wife's computer and in my HTPC work perfectly well, had them for years, but they're too damn loud.

Can I just unplug the fan inside and replace it with a quieter one, or maybe put an inline resistor in? The HTPC only draws about 60-70W at the very most, but her PC can draw 250W when playing games.

 

[Tsumi]

You can. I would just get two CX430's when they go on sale though.

What is the specific model of your PSU's?

 

[larrymoencurly]

Changing to a quieter fan of the same airflow rating will probably help more than anything else.

If you add an inline resistor rated for 12/(fan amp rating) ohms, you'll drop the fan voltage by about half because fans tend to draw half their rated amps. Don't do this if the fan is already temperature controlled because the voltage could become too low for the fan to start. Be sure to use a resistor rated for enough watts, at least 144/ohms, preferrably twice that because resistors get hot enough to melt plastic or burn stuff when operated at their rated wattage. Or instead of a regular resistor, use a thermistor (NTC type) of that ohm rating at room temperature to make the fan speed vary with temperature, and attach it to the LOW VOLTAGE heatsink closest to all the red, black, yellow, and orange wires going to the computer or to the bigger LOW VOLTAGE donut coil next to it. Cover each wire lead of the resistor or thermistor individually with high temperature heatshrink tubing (polysulfone or teflon, not PVC) and the whole thermistor with in the same kind of heatshrink as well. I emphasize "LOW VOLTAGE" because there are high voltage donut coils in the AC line filter and high voltage heatsinks for the power factor correction and inverter transistors, and you have to keep everything away from them. You can probably glue the thermistor between the heatsink fins or in the donut coil's hole with silicone rubber sealant.

 

[fattypants]

Thanks for the information guys! I think I'm going to swap the fans out, since I don't want to melt any resistors...

I'm not sure what the models are, they're both decent brands I'm sure (I learned my lesson on cheaping out on PSUs a decade ago), but I bought them before silence was my main concern.