A Detailed Look
The Cooler Master MasterWatt 550W power supply enclosure is painted matte black and measures 140mm (5.5”) deep. The back panel includes an AC receptacle and main power On-Off switch. The PSU features semi-fanless operation, which keeps the fan from spinning when the output power is below 15%.
The Cooler Master Silencio fan (DF1202512RFLN) is rated for 0.16A and 2500 rpm at 12 VDC. The fan incorporates a Loop Dynamic Bearing (LDB) for long life and quiet operation. This appears to be another variant of a Fluid Dynamic sleeve bearing.
The front panel on the MasterWatt 550W PSU incorporates three modular cable connectors for the three modular peripheral cables.
The three modular cables are flat ribbon-style for easy cable routing.
Under the Hood
Here are a few pictures showing the layout and components inside the MasterWatt 550W Bronze power supply. Cooler Master appears to be using the HEC Group as the OEM for the MasterWatt series.
The PSU incorporates DC-to-DC converters to generate the +3.3V and +5V outputs from the +12V supply. The layout of components and the soldering appears to be good. The capacitors are primarily made by Teapo. For example, the primary bulk capacitor is made by Teapo and is rated for 330uf, 400V and 85°C.