Power supply fan upgrade

If you’ve read my previous post you’ll know that I already own some pretty fancy equipment. One of the less fancy things that I own is a rather cheap bench power supply, the Tenma 72-10500. It’s just a re-branded Korad power supply. While being cheap these power supplies still offer great value for your money.
However, one of the really annoying things of this power supply are the two fans. They are loud – really loud. So loud that I decided to replace them with some more decent fans.

Note: This is not going to be a review of any kind. Everything stated in this article is just my personal opinion.

Taking off the hood

Quite obviously the first step was to take a look inside and see what kind of fans this device uses. Although this is quite a cheap unit, the engineer who designed this certainly put some thoughts into it.PowerSupply opened 2 One of the fist things that I noticed that I really like is the fact that all mains cabling connections has been heat shrunk. Furthermore all the earth connections have crimped ring terminals that have been screwed down with shake-proof washers – you won’t find this in every cheap Chinese device.

The heat sink assembly

The heat sink assembly is actually another neat thing in this unit. I’ve never that kind of setup before but personally I like it very much.As you can see it will be very easy to replace the fans on the heat sink assembly as the heat sink and the PCB are connected through separate screws.

Heat Sink Assembly
Heat Sink Assembly
Heat Sink Assembly
Heat Sink Assembly

Choosing the right fans

The fans used in this power supply are standard 80 x 80 x 20 mm computer case fans. Hence there will be a variety of fans to choose from. Arctic Cooling F8Sadly I don’t own an air flow meter to measure the amount of air that is being moved by the stock fans. However, I couldn’t really care anyway and decided to use my favorite computer case fans: The Arctic Cooling F series case fans.

Replacing the fans

Due to the simple mechanical setup of the heat sink assembly replacing the fans was a real peace of cake. Sadly the old fans didn’t use the three pin Molex connectors but the two pin JST series connectors instead. Heat sink assembly with new fansAs I didn’t have any JST connectors around I decided to simply cut of the cable of the old fans and solder it to the cable of the new fan. A bit of heat shrinking tubing protected the solder joints against shorts and all that’s left to do was screwing the new fans to the heat sink.

In case you’re wondering which stock fans are used in this device, they are JSF branded JSF8025MS.

Tenma 72-10500 stock fans
Stock fan vs. Arctic Cooling F8

Conclusion

The power supply is still louder than I expected but definitely way more quiet than before. The problem is that in this case it’s not really the fans themselves that are generating a lot of noise but the air that they pull through the sharp edges of the heat sink that is mounted very closely to the fan.
I took a picture of the noise before and after the modification:Before After comparasionAs you can see there’s quite a notable difference. The power supply operates a lot more quiet after the modification.

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