SilverStone DA850R Gold 850W Report (Page 3 of 4)

Page 3 - Physical Look - Inside

As always, we opened up our SilverStone DA850R Gold 850W power supply to take a detailed look at what is going on inside. Please note that doing this at home will likely void your 5-year warranty, as one screw has a seal over it that says "electrocution risk if opened" as mentioned on the previous page. It technically does not say opening it will void its 3-year warranty, but the warranty terms on the website strongly implies that. For the benefit of you, we cracked ours open, so you do not need to. There are no user serviceable parts inside. It is important to note the 3-year warranty is shorter than the industry standard of 5 to 10 years for mainstream PSUs nowadays.

Disassembling the SilverStone DA850R Gold 850W is quite straightforward with the removal of four to six screws, depending on how far you want to get. Our photo above shows an overhead view of its internal components. Its OEM is Andyson, which has a mixed reputation for quality. This is different than the SilverStone Decathlon DA850 Gold 850W, which was built by CWT, a manufacturer that has always been very solid. The DA850R features an LLC full bridge topology with DC-to-DC converters. At first glance, the build quality appears to be very good. There are four main heatsinks inside, all unpainted. Three are located on the primary side, while one resides on the secondary side.

Pulling the enclosure apart and we got straight to the internal inspection. The transient filter stage is the first input stage of a computer power supply, so we will take a look at that first. SilverStone has always done a great job in the past to make sure their power supplies met or exceeded the recommended requirements, and the DA850R Gold 850W is no exception. The SilverStone DA850R Gold 850W has one metal oxide varistor, two metalized polyester X-capacitors, four ceramic Y-capacitors, and two common mode chokes. This is two times the amount of X and Y capacitors than recommended. Considering some PSUs have missing MOVs, I am happy to see it here as this component is used to stabilize spikes from the AC line.

The active PFC circuit featured on the SilverStone DA850R Gold 850W uses two bridge rectifiers on both sides of the heatsink closest to the transient filter stage. Unfortunately, I was unable to see their brand and part number.

On the largest heatsink shown in the above photo, there is one WeEn BYC10-600P Hyperfast power diode attached to it as the APFC boost diode. Meanwhile, on the same heatsink, there are two Sanrise Tech SRC60R140BS power MOSFETs placed. Each is certified for up to 15.8A at 100c. These transistors present a maximum resistance of 140 mΩ and typical resistance of 126 mΩ when turned on according to the manufacturer's data sheet. This on characteristic is called Static Drain-Source On-Resistance, or commonly abbreviated as RDS(on). The more efficient the component is, the lower the RDS(on) value, since it wastes less power with lower resistance.

On the primary side, we can see two Taiwanese-made LTEC capacitors. Our 850W version of SilverStone's DA850R Gold power supply incorporates two 390µF x 420V capacitors in parallel for an equivalent capacitance of 780µF x 420V. It is rated at 105c, whereas more value-oriented power supplies usually use 85c rated capacitors.

Further down the line, we can see four Magnachip MDF18N50 power MOSFETs for primary switchers. They are located on the pi-shaped heatsink between the bulk capacitors and the transformer, with two on the same side of each leg. Each is rated for up to 11A at 100c. These transistors present a maximum resistance of 27 mΩ and typical resistance of 22 mΩ when turned on according to the manufacturer's data sheet.

Champion's CU6901VPA is the switching controller, located at the back of the main board.

On the secondary side, we can see more Chinese-made and Taiwanese-made electrolytic capacitors from Jun Fu and Teapo, respectively, rated at 105c. As with modern high efficiency power supplies, all rectifiers produce the +12V out, while the +5V and +3.3V outputs are generated from the +12V output using a DC-to-DC converter within the power supply unit. Six All Power Semiconductor G013N04G MOSFETs are responsible for generating the +12V output, located at the back of the PCB, as shown. The G013N04G's rated continuous drain current is 100A at 100c. It has an RDS(on) value of 1.8 mΩ typical. Also found on the back is a Weltrend WT7527RA monitoring IC that provides over current and over/under voltage protection.

It appears there are four MOSFETs on the add-in board parallel to the rear modular cable daughterboard that generate the +5V and +3.3V output from the +12V rail. Unfortunately, I could not identify the parts. On the same PCB, we can find an ANPEC APW7159C, which is the PWM switching controller. The datasheets for all components mentioned in this review can be found on their respective manufacturers' websites.

At the back, we have a large daughterboard covering the majority of the rear panel for the modular cable sockets. All modular sockets at the bottom are soldered directly to the main PCB after the secondary stage. Pin headers join the mainboard and daughterboard to reduce power transmission loss. The output connector configuration can be seen on the previous page.

Overall, the internal build quality of SilverStone's DA850R Gold 850W power supply is very good -- definitely positive news for an Andyson-built unit. Components are arranged very well for optimal cooling with minimal wires running around inside, and solder points on its black PCB is quite clean in general. I would say the SilverStone DA850R Gold 850W is lower tier with regards to the selection of components used under the hood, as it consists of exclusively Chinese and Taiwanese-sourced budget parts.

Lastly, we see a 120mm fan that provides cooling to the SilverStone DA850R Gold 850W's internal components. It is connected to an add-in board with a Weltrend WT51F104 microcontroller using a 2-pin connector. A 120mm fan is rather small nowadays for a power supply with a bottom mounted fan, but if not a lot of heat is being generated, noise will be kept to a minimum.

The fan model is Poweryear PY-1225H12S, as shown in our photo above. The PY-1225H12S is a sleeve bearing fan specified at 0.35A. The fan is not supposed to activate until the PSU is loaded to approximately 340W with semi-fanless mode active. As such, it should remain off for the most part, and even when it is on, the fan speed will vary with load. Fans with sleeve bearings have shorter lifespans compared to ball or fluid dynamic bearing fans, but are quieter than ball bearing fans and costs less than fluid dynamic bearing fans.

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