As we mentioned on other articles, the first place we look when opening a power supply for a hint about its quality is its filtering stage. The recommended components for this stage are two ferrite coils, two ceramic capacitors (Y capacitors, usually blue), one metalized polyester capacitor (X capacitor), and one MOV (Metal-Oxide Varistor). Very low-end power supplies use fewer components than that, usually removing the MOV, which is essential for cutting spikes coming from the power grid, and the first coil.

This power supply from HEC has more than the minimum recommended number of components for this stage. In addition to the above list, it uses one extra metalized polyester capacitor (X capacitor), see Figures 9 and 10.

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Figure 9: Transient filtering stage (part 1).

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Figure 10: Transient filtering stage (part 2).

A very interesting feature from this power supply is that its fuse is inside a fireproof rubber protection. So this protection will prevent the spark produced on the minute the fuse is blown from setting the power supply on fire.

In the next page we will have a more detailed discussion of the components used in the WinPower 480 W.