SilverStone Decathlon DA850 Gold 850W Report (Page 3 of 4)

Page 3 - Physical Look - Inside

To begin our internal inspection of the SilverStone Decathlon DA850 Gold 850W, I opened up the PSU. Please note doing this at home may void your 5-year warranty thanks to a seal that extends over one edge of the power supply. But for your benefit, I disassembled mine, so you do not need to. There are no user-serviceable parts inside.

Taking apart the SilverStone Decathlon DA850 Gold 850W is quite straightforward with the removal of four screws next to the fan mount. The photo above shows an overhead view of its internal components. The OEM is Channel Well Technology or CWT, which is a reputable OEM since 1993. At first glance, the build quality appears to be excellent. There are five main heatsinks inside, with three of them using a black color scheme while the other two being silver.

Starting with the transient filter stage, we find ourselves with two metalized polyester X-capacitors, two ceramic Y-capacitors, two ferrite coils, and one metal oxide varistor or MOV. This is two times the number of X-capacitors than recommended, which is always nice to see. It is also great to see the MOV, which is used to protect the power supply from AC voltage spikes. Not all modern power supply units have one, so it is good to spot one here.

On the primary side, we can see a single Japanese-made Nichicon capacitor. 100% Japanese-made capacitors are one of the main selling points of the SilverStone Decathlon DA850 Gold 850W, so this is a good start. Our 850W version of the DA850 series power supply incorporates one 470uF x 400V capacitor. This Nichicon capacitor is rated at 105 degrees Celsius, which is much better than the more value-oriented 85 degrees Celsius rated capacitors out there.

The active power factor correction or APFC circuit uses a single Lite-On Semiconductor GBU1506 rectifier bridge attached to the first heatsink. At 115V, it has a rated current of 15A at 100 degrees Celsius, so you can theoretically pull 1725W (15A * 115V * one diode). This, of course, is limited to the fact that it is not 100% efficient, just like any electrical component or device. This also neglects the fact that other components are unable to keep up. Either way, this far exceeds the 850W this power supply unit is rated for.

Moving forward, we have two GP28S506 power transistors directly attached to the largest heatsink. However, I was unable to find any further information regarding these transistors. Next to the power transistors is an ON Semiconductor FFSP0665A Schottky diode. Four transistors responsible for the main switching on the APFC circuit are located further down, with two of them located towards the left side of the largest heatsink separated by the Nichicon capacitor and the other two on a smaller heatsink directly behind. Two of these transistors are Silan Microelectronics SVF20N50F N-channel MOSFETs. These devices have a maximum Static Drain-Source On-Resistance of 270 mΩ and a typical resistance of 200 mΩ. It is important to note that the lower the resistance on these transistors are, the more efficient these components will be. This is because the Static Drain-Source On-Resistance, or RDS(on), will dissipate power, so the smaller the resistance, the less power wasted. I am unfortunately unable to clearly see the label on the remaining two transistors in the APFC section due to how tightly spaced these devices are. Another important component to note is the Champion CM6500UNX PFC controller located at the bottom of the main printed circuit board.

On the secondary side, we have a collection of smaller capacitors all rated at 105 degrees Celsius. There is a mix of Chemi-Con and Rubycon capacitors here, which are both Japanese brands, living up to their claim of 100% Japanese-made capacitors, adding to the quality of this power supply unit. Eight International Rectifier IRFH7004PbF transistors are located at the bottom of the large PCB, which are responsible for generating the +12V output. The continuous drain current for these devices is 164A at 100 degrees Celsius. The typical RDS(on) value is 1.1mΩ and the maximum RDS(on) value is 1.4mΩ. On the smaller daughterboard placed just before the output, we have six Sync Power Corporation SPN3006 N-Channel Enhancement Mode MOSFET transistors responsible for generating the +5V and +3.3V output. The continuous drain current for these devices is 57A at 100 degrees Celsius. The typical RDS(on) value is 4.7mΩ and the maximum RDS(on) value is 5.5mΩ. A Champion CM6901X PWM controller is located at the bottom of the board, not visible in the photo. Finally, we can also see a SITRONIX ST9S429-PG14 IC chip on the top layer of the board, which is responsible for overvoltage, overcurrent, overheat, and short circuit protection. The datasheet for all the components mentioned is found on their respective manufacturer’s websites.

Since this is a fully modular power supply, we have a large daughterboard at the output side for the modular cable connections. All connectors at the bottom of the daughterboard are soldered directly to the main PCB after the secondary stage to reduce power transmission loss. The output connector configuration is shown on the previous page. Overall, the internal build quality of SilverStone’s Decathlon DA850 Gold 850W is very good. Aside from a few glue glops, which is normal, the components are arranged very cleanly for optimal cooling with practically no wires running around inside. The solder points on its black PCB are acceptably clean in general. I would say the SilverStone Decathlon DA850 Gold 850W is generally good with regards to the selection of components used under the hood; appropriate for its performance class.

In terms of cooling performance, there are two things we need to pay attention to for a power supply unit; namely the heatsinks and cooling fan. In this case, we can see multiple heatsinks and one cooling fan inside SilverStone’s Decathlon DA850 Gold 850W. The layout of heatsinks inside the power supply unit is well-thought out to fit into such a relatively tiny enclosure. However, one small thing to point out is how the two silver heatsinks have no electrical components connected to them, which I find a bit odd. Nonetheless, extra heatsinks never hurt anyone.

The OEM of fan is Yate Loon, with D12BH-12 as the model number. The size of the fan is 120mm in diameter, which is the maximum the enclosure is able to accommodate. Further research indicates the D12BH-12 is a fluid dynamic bearing than that runs at a current of 0.3A for a maximum RPM of 2300. The rated airflow is 89 CFM at a noise level of 41 dB.

Page Index
1. Introduction, Packaging, Specifications
2. Physical Look - Outside
3. Physical Look - Inside
4. Minor Tests and Conclusion