Dis-Assembly
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The input filtering starts at the AC receptacle, with an X-Capacitor and two Y-Capacitors located there. The main PCB adds another X-Capacitor, two coils, two Y-Capacitors, and two MOVs, bringing the total number of components up to two X-Capacitors, two coils, four Y-Capacitors and two MOVs. The bridge rectifier used is rated for 8A, which is more than good enough for a 400 Watter. The two primary capacitors are 680µF parts made by Teapo. Screwed on to the main heat sink are two Toshiba 2SK3568 MOSFETs, which are used as the switching transistors, in a two transistor forward configuration. They are controlled by an ST Micro UC3845B Current Mode PWM controller.
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The capacitors used on the secondary side are Taiwanese parts made by OST. They are much better than many other Taiwanese and Chinese brands, and can sometimes hold up OK if they aren’t stressed much. However, more reliable Japanese parts would still be preferable.
The 12V rail uses two Diodes Inc. SBR20100CT rectifiers rated at 20A each. This means that the 12V rail would be capable of up to 40A. The 5V and 3.3V rails use STPS30L45CT and STPS3045CW rectifiers respectively. Both of these rectifiers are rated at 30A, so it would be safe to assume that both of these rails are capable of 30A. The supervisor IC is a Weltrend WT751002. It supports Over Voltage and Under Voltage Protection, but lacks Over Current Protection support, so this is really a single rail power supply, because OCP is required to separate the 12V rails.
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The soldering quality is generally very good. All of the joints have an appropriate amount of solder, and the component legs are all cut to appropriate lengths. The main toroid coil on the secondary side looks like it was soldered in by hand, as there is some residue flux, and the soldering doesn’t look quite as tidy as the other joints. This is unlikely to cause any problems, though.
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This power supply is cooled by an ADDA sleeve bearing fan – an AD1212MS-A70GL. ADDA don’t have any specs available on their website, but they do have specs for the similar -A71GL and -A72GL, Both of which have speed, airflow and noise ratings of 2050RPM, 80.5CFM (Cubic Feet per Minute), and 30dB respectively. I’ll wager that this fan has similar if not identical specifications. I wouldn’t say that ADDA are the most reliable of brands, but they are still miles better than many others. The heat sinks aren’t massive, but the fan was actually fairly quiet under light loads, such as what the average home or office computer would draw. It got a bit louder at higher loads, but it was never what I would consider disturbing.
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