A Look Inside & Component Analysis

Before reading this page, we strongly suggest a look at this article, which will help you understand the internal components of a PSU much better. Our main tool for the disassembly of the PSU is a Thermaltronics TMT-9000S soldering and rework station. It is of extreme quality and is equipped with a matching de-soldering gun. With such equipment in hand, breaking apart every PSU is like a walk in the park!


The V1200 uses Seasonic's top platform, the XP3, an upgraded version of the KM3 platform we have come across in many of our reviews. The primary side uses a full-bridge design and an LLC converter for lossless switching, and the secondary side employs a synchronous design with the +12V fets on the main PCB, which is the same setup as in the KM2 platform, while the DC-DC converters are installed on the modular PCB for decreased power losses. All the components used are only of the highest quality, which is the norm for a Seasonic product.


Right behind the AC receptacle is a sealed PCB that hosts some of the components of the EMI filter: a CM choke, four Y caps, and a single X cap. The filter's other components are on the main PCB and include two pairs of X and Y caps, two CM chokes, and an MOV.


The thermistor that protects the unit against large inrush currents and the corresponding electromagnetic relay that isolates it from the circuit once the APFC caps are fully charged.


Two parallel bridge rectifiers are used, and both are bolted to a dedicated heatsink.


The APFC converter uses three Infineon IPP60R125CP fets and a single SCS110AG boost diode. The three parallel hold-up caps are provided by Hitachi (420 V; 330 µF the two of them and 390 µF the last one or 1050 µF all of them combined; 105°C; HU series).


This small daughter-board right between the heatsinks houses the PFC controller, an NPC1654 IC.


The full bridge topology uses four Infineon IPP50R199CP fets. An LLC resonant converter is also used to boost efficiency.


The LLC resonant controller, a Champion CM6901 IC, is hiding behind the middle bulk-cap, so we had to remove it to provide you with a clear view.


There is a quite large heatsink that doesn't hold any mosfets in the top of the secondary side. It plays an active role in cooling down the +12V fets right below it, on the solder side of the PCB. The latter consist of eight Fairchild FDMS015N04B fets that are cooled by the aforementioned heatsink and the enclosure itself.


All capacitors in the secondary side, polymer and electrolytic, are provided by Nippon Chemi-Con, so they are of very good quality.


The VRMs (Voltage Regulation Modules) handling 5V and 3.3V are installed directly on the modular PCB to drastically reduce impedance and the distance the minor rails have to travel. Each VRM has three Infineon BSC0906NS fets, and one APW7159 PWM controller handles both regulators.


Every modular socket on the bottom is directly soldered to the main PCB via thick metal conductors that minimize the amount of energy lost on them.


Several polymer caps on the front of the modular PCB improve ripple suppression, and the chokes and the polymer caps that are exploited by the DC-DC converters are also here.


This board, right at the edge of the secondary side, holds a Weltrend WT7257V supervisor IC and an AS393 dual-voltage comparator. The supervisor IC supports OCP for up to two +12V virtual rails, though the V1200 only has one.


The standby PWM controller is an ICE2QR4765 IC.


Soldering quality is great, and the solder side of the PCB is, strangely enough, green, which is contrary to the red color of the main side.


The V1200 uses exactly the same fan as the V1000, which is great since CM spared no expense by picking a Dynamic Fluid Bearing fan by Protechnic, one of the best fan manufacturers out there. These FDB fans are among the best money can buy today because their longevity and low noise output is unmatched. The fan's model number is MGA13512XF-025 (135 mm, 12 V, 0.38 A), and like in our V1000 review, we just have to praise CM for such an impeccable pick.