Silent Fanless Computer Power Supply


Silent Fanless Computer Power Supply

 

Silent Fanless Computer Power Supply

 


There are a few different ways of doing this but basically you have to make the heatsinks NOT live and you have to provide better cooling for the transistors.

The heatsinks used in PSUs are generally soldered to the PCB via little metal tabs and current usually flows through them, ie they are live with voltage and act as part of the circuit. What you have to do is cut the tabs which takes the heatsinks out of the circuit and them use wire to replace them in part of the circuit.

Silent Fanless Computer Power Supply

The second part can be done various ways eg. make heatinks that replace the existing ones and attach them onto a bigger heatsink (thats what I did below) or extend the transistors with wires and attach them directly to the big heatsink.

I tried this method on three PSUs all with no luck. The PSU would whine or hiss after adding the wires. I tried making the wires really short and I checked all my connections repeatidly. I asked a PSU repair guy why and he said that it was the extra resistance the wires made in the circuit that caused the noise. He aslo said that it may seem like a really tiny difference but it was because the opperate at a very high frequency. I wanted a REALLY silent PSU so I was particularly fussy about the noise it produced so if you did the same you might not notice or care. Maybe I just had bad luck and picked the wrong PSUs, I dont know but it worked like this anyway:



I was lucky and got a 150 watt Micro ATX PSU in which the heatsinks were grounded.



There are a few different ways of doing this but basically you have to make the heatsinks NOT live and you have to provide better cooling for the transistors.



The heatsinks used in PSUs are generally soldered to the PCB via little metal tabs and current usually flows through them, ie they are live with voltage and act as part of the circuit. What you have to do is cut the tabs which takes the heatsinks out of the circuit and them use wire to replace them in part of the circuit.



It might look like this when done (the wires are where the metal tabs were):



The second part can be done various ways eg. make heatinks that replace the existing ones and attach them onto a bigger heatsink (thats what I did below) or extend the transistors with wires and attach them directly to the big heatsink.



I tried this method on three PSUs all with no luck. The PSU would whine or hiss after adding the wires. I tried making the wires really short and I checked all my connections repeatidly. I asked a PSU repair guy why and he said that it was the extra resistance the wires made in the circuit that caused the noise. He aslo said that it may seem like a really tiny difference but it was because the opperate at a very high frequency. I wanted a REALLY silent PSU so I was particularly fussy about the noise it produced so if you did the same you might not notice or care. Maybe I just had bad luck and picked the wrong PSUs, I dont know but it worked like this anyway:



I was lucky and got a 150 watt Micro ATX PSU in which the heatsinks were grounded:



I had to remove a capacitor to unscrew the transistors from one the heatsinks:



The other I had to completely remove transistors and all because there was no way to get a screw driver in there to remove the screws on the transistors.

I had to remove a capacitor to unscrew the transistors from one the heatsinks.

I then made similar heatsinks out of plain 5mm aluminium. I did this because the original ones were going to be very difficult to bolt to a big heatsink.

Silent Fanless Computer Power Supply

Silent Fanless Computer Power Supply

Silent Fanless Computer Power Supply

Silent Fanless Computer Power Supply


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