Page 3 - Physical Look - Inside
In order to further investigate the design details of the SilverStone Essential Gold ET750-HG 750W power supply unit, some panel removal is required. It is important to note two important concerns before disassembling any power supply unit. First, certain components, such as the capacitors, may cause an electrical shock; and second, your three-year warranty will be voided if the screws on the power supply unit are removed. Therefore, unnecessary disassembling of a power supply unit should be avoided. Once the top panel of the ET750-HG 750W is removed, a closer look of the electronic components can be revealed. The OEM for the power supply is Channel Well Technology or CWT for short.
Let us first take a look at the transient filter stage of the power supply unit. The function of the transient filter stage is to protect the computer from the power grid noise and voltage spikes. In the SilverStone Essential Gold ET750-HG 750W power supply unit, the transient filter stage contains a metalized polyester X-capacitor and two Y-capacitors behind the power plug. On the main PCB, the transient filter stage continues; there are several ferrite coils, one metal oxide varistor, one X-capacitor, and two Y-capacitors. The transient filter stage of this product is complete. There is also a MOV here is to prevent the computer from being damaged by surges. It is worth mentioning not all the power supply units in the market have an MOV.
Now, we move on to the primary side. The big capacitor in the photo is a Nichicon capacitor, which is rated at 560uF at 400V and 105c. It is a Japanese brand capacitor, therefore it may have a higher cost, but the quality would be better compared with the capacitors made in other countries. I am happy to see a 105c rated capacitor here. It is definitely better than those 85c rated capacitors. This is because the PSU will normally generate a lot of heat at high workload and having this higher temperature rating will increase its reliability.
In the above photo, we can see there is a long heatsink located right beside the large capacitor. There is a rectifying bridge attached to the rightmost side of that heatsink. From what I can see, the rectifying bridge is a GBU1506. At 115V, the maximum rectified forward current capacity with heatsink is 15A, so you can theoretically pull up to 1725W (15A * 115V) from the bridge rectifier at 100% efficiency -- of course, this is limited by the fact that it is not 100% efficient, and also neglects the fact that not every component in the system are able to keep up. On the left side of the rectifying bridge, there is one Infineon D0865C5 diode and two GP28S506 transistors on the big heatsink. The IC for the PFC controlling unit is the Champion CM6502S. The standby PWM controller is the TNY177PN from TinySwitch. In photo, you can also see a small PCB daughter board installed behind the modular cable sockets PCB. On that daughter board, there is a Champion CM6901 resonant controller.
The electrolytic capacitors on the secondary side are not manufactured in Japan. Some of these electrolytic capacitors are made by CapXon, which is a Hong Kong based company with their manufacturing facility in China. Other capacitors are made by Jun Fu from China. The polymer capacitors are not from any Japanese company either; they are made by APAQ Technology from Taiwan. Considering this is a budget power supply, I do not expect the ET750-HG 750W will be equipped with all Japanese capacitors. You will need to see how this holds up in the long run though. For a modern power supply unit, the power output from the rectifiers is +12V. The +12V output of the power supply unit can just directly use the power from the rectifiers; however, the +5V and +3.3V outputs are converted from the +12V output. The conversion functionality is mainly realized by the components on the DC-DC daughterboard, where you can find an APW7159 synchronous buck PWM controller and four UBIQ QM3006D MOSFETs handling the +5V and +3.3V outputs. For current protection, there is a Sitronix ST9S313-DAG on the main PCB. More information about these parts can be found from their respective datasheets from the manufacturer's website.
In terms of cooling performance, there are two things we need to pay attention to for a power supply unit; namely the heatsink and cooling fan. In this case, we can see more than one heatsink and one cooling fan inside of the ET750-HG 750W. The number of heatsinks inside the power supply unit is abundant thanks to the roomy chassis. The size of the fan is 140mm in diameter, which is appropriate for this enclosure. According to the label on the fan, the D14SM-12 fan is made by the Yate Loon Electronics.
Page Index
1. Introduction, Packaging, Specifications
2. Physical Look - Outside
3. Physical Look - Inside
4. Minor Tests and Conclusion
