EnergyKnight SS-350ET-T3: the cheapest Seasonic unit (updated)

Secondary side

On the secondary side of the SS-350ET-T3 there are the Schottky diode rectifiers, compared to previous platform, axially switched between left and right. So now the +12V rectifiers, PFC Device Corporation PFR30L50CT (30/250 A, 50 V, 0.54 V @15 A/25 °C, 0.5 V @125 °C), are on the right side. There is a copper plate under the front rectifier which helps conducting the current. There is one blank spot for higher rated versions of this platform (going up to 600 W). You can see both the filtering capacitors, Teapo SJ 2200/16, in front of them. Also no sign of any multiple “rails” anywhere. There is also space for larger capacitors and more cabling for higher versions. The +5 V rail has ST Micro STPS30L30CT (30/220 A, 30 V, 0.57/0.5 V @30 A) and SJ 2200/10+SC 1000/10. The +3.3 V has separate inductor, as you can see, because it uses mag-amp for generation from +5 V transformer output. Its rectifier is also STPS30L30CT, filtering capacitors are SJ 2200/10 with SY 1000/10.

Finally the −12V rail uses auxiliary winding on the common +5/+12 V inductor, small diode and Teapo SC 220/16. The secondary monitor (supervisor) is the HawYang HY-510N on a daughterboard by the +3.3 V rail. Besides providing the ordinary functions (Power Good) it also monitors OVP, and UVP (only for +3.3 and +5 V rails though). There is no OCP or other capability in this IC. The fan controller circuit uses SMD thermistor on the central transformer tap, and CYStek (CYStech Electronics Corporation) BTN1053I3 (2.5/5 A, 80 V) NPN transistor in TO-251 package.

Build quality

As usual, I’ll focus on the overall build quality and other things like electrical safety here, as the quality of the components that were used has already been discussed before. The separation between the primary and secondary side is good. There is also some drilling under the main transformer for better cooling and some creepage slots under the stand-by transformer. You can also see rubber spacer. As already stated, thermistor does not come with heatshrink. Component insulation is mostly good, on the other hand for my taste there is way too much silicone in the unit.

The soldering looks nice on first look, and it is true there was only single solder ball. But there are quite many manually resoldered joints, especially the larger ones, which (as usually) nobody cleaned afterwards. And many of the smaller joints look far from good enough to me, so alltogether I’d remove all the 10 base points.

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