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 platform is the same as in Seasonic's new high-end models (SS-1250XM2, SS-1200XP3 and SS-1050XP3), with some minor changes in parts. The primary side consists of a full-bridge topology with an LLC converter for lossless switching, while the secondary side employs a synchronous design with the +12V fets installed on the main PCB's solder side. Both DC-DC converters are on the modular PCB to reduce power losses, a technique Seasonic has employed for some years now.


The sealed PCB behind the AC receptacle holds a CM choke, four Y caps, and an X cap. The transient filter's other components, two X and Y caps, each, two CM chokes, and an MOV, are on the main PCB. There is also an NTC thermistor. It protects the unit from large inrush currents and comes with a relay that isolates it once it finishes its job.


Two bridge rectifiers (GBJ2506) are used, and they can handle up to 50 A of current combined.


The APFC converter uses three Infineon IPP50R199CP fets and a single STPSC806D boost diode. The three parallel hold-up caps are by Nippon Chemi-Con (420 V; 330 μF each or 990 μF combined; 105°C; KMR series).


The PFC controller on the small vertical PCB above is an NPC1654 IC.


The full-bridge topology uses four Infineon IPP50R399CP fets and an LLC resonant converter to boost efficiency.


The LLC resonant controller, a Champion CM6901 IC, is on a vertical PCB right behind the bulk-cap in the middle.


The +12V fets, four NXP 2R640s, are installed on the solder side of the main PCB. The enclosure and a large heatsink cool these down. The latter is depicted in one of the photos above. All capacitors in the secondary side, polymer and electrolytic, are provided by Nippon Chemi-Con.


On the rear of the modular panel are the two VRMs responsible for the generation of the minor rails. Each VRM utilizes three Infineon BSC0906NS fets, and a single APW7159 PWM controller handles these regulators.


There are many FPCAP (Japanese) polymer caps on the front. While most are used for filtering purposes, some are for the DC-DC converters.


The lower sockets of the modular PCB are directly soldered to the main board for decreased energy losses on power transfers at, in particular, higher loads.


The standby PWM controller is an ICE2QR4765 IC.


A large daughter-board holds the supervisor IC, a Weltrend WT7257V, and an AS393 dual-voltage comparator. The WT7257V supports OCP for up to two +12V virtual rails, but the X-1050 only has one on paper.


Soldering quality is very good, which is as expected of a high-end Seasonic unit.


The cooling fan's model number is 9S1212H403, and it is by Sanyo Denki. It uses a pair of ball-bearings, which should have it last a long time (40,000 hours according to its manufacturer, at 40°C and full speed). Unfortunately, it is especially noisy at high speeds. We believe Seasonic should use a quieter FDB fan instead.