Disassembly
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The input filtering is completely inadequate, consisting of just two Y-Capacitors. There are no coils or X-Capacitors. There is also no bridge rectifier – just four 3A diodes. The switching transistors are Fairchild FJP13009s rated at 12A each, in the rather dated half-bridge configuration. The screws on the switching transistors were done up very loose – so loose that I undid them with nothing but my bare fingers.
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The capacitors are all made by Kingcon – a brand nobody seems to know much about. As a rule of thumb, if a capacitor is not from one of the respected manufacturers, then it should be assumed to be of low quality.
The 12V rectifier is the one on the right. It’s a JD Semiconductors 16F020C, which is a fast recovery rectifier rated at 16A. Considering that the label claims 24A worth of 12V capacity, this part is insufficient. It would also have been better to use a schottky rectifier for greater efficiency. The 5V rectifier is an SB3045ST Schottky rectifier rated at 30A, and the 3.3V rail uses a JD Semiconductors 20S45 20A schottky rectifier. The 12V rectifier’s screw was also loose enough to undo without any tools. The other two were more tightly done, though. The controller IC used is an EST7502B supervisor/PWM controller combo IC. The only protections it supports are Over Voltage and Under Voltage Protections. It lacks Over Current Protection, so this is a single rail power supply.
The soldering quality is passable, but there are a few messy looking joints on the secondary side. This probably won’t cause any problems, though.
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Ah, now I know who the OEM really is – Mary. How do I know? It has a wittle Wam. Jokes aside, the fan did stay very quiet throughout the testing, in spite of being wired directly to 12V. I have also started peeling the labels off fans and checking the bearing housing for lubricant. Thankfully, this fan had adequate oil and the plug had a tight seal. The heat sinks aren’t too tiny, but they could be larger.
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