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 FSP Twins 500 W consists of a frame and two power modules. The frame includes the DC-DC converters that generate the minor rails, along with the -12V regulation and digital communication circuits. The power modules generate the +12V rail and 5VSB outputs and feature a digital design with two MCUs to handle the control functions. These MCUs are also responsible for the digital link to the frame.

On the primary side of the modules is a half-bridge topology, while a synchronous design is utilized to generate the +12V rail in the secondary side. The modules' filtering caps are of high quality, and in addition to electrolytics, FSP uses a number of polymer caps for increased reliability.


The transient filter starts at the AC receptacle and includes - in this case - two Y caps and a single X cap. It continues on the main PCB with the same number of Y and X caps, along with two CM chokes and an MOV. There is also an NTC thermistor for protection against large inrush currents. An electromagnetic bypass relay supports this thermistor.


The single GBU1506 bridge rectifier is bolted to a dedicated heat sink.



One Infineon IPA60R165CP FET is used in the APFC converter, along with an IDH06G65C5 boost diode provided by the same manufacturer. The bulk caps come from Nichicon and have a much longer lifetime (2.5 times as much) than the bulk caps we usually find in high-end desktop PSUs.


The primary switching FETs, two Infineon SPA11N80C3s, are configured in a half-bridge topology.


Two MCUs are installed in each of the power modules. One handles the control functions, while the other most likely handles the digital link to the frame. The first MCU is a Texas Instruments MSP430AFE253 and the second is a Microchip PIC24FJ32GA.


The +12V rail is rectified by a pair of NXP PSMN2R2-30YLC FETs in the secondary side of these modules. The electrolytic and polymer filtering caps are from Chemi-Con and of high quality. There are no KZE caps in the Twins, only the higher-quality KY and KZH ones. Given how little space there is inside each module, which limits airflow, and the overpopulated PCB, it is good to see FSP using electrolytic caps with a longer lifetime.


There's a very basic protections IC on this board, the HY-510N. One of the MCUs probably also handles some of the protection features.


The 5VSB circuit is installed to a vertical daughterboard. Its main rectifier is a 30A60CT SBR, cooled by a small heatsink.


Soldering quality is good, but FSP's PCB isn't that robust. It didn't cope with the high temperatures of our desoldering tools very well.


A 40 mm diameter fan, sourced by Protechnic Electric, cools each module. Its model number is MGT4012ZB-W28, and it uses a dual-ball bearing, which should have it last a long time. Expect this ultra-high-speed fan to make a lot of noise if you push these modules hard.


The Twins frame hosts DC-DC converters for the minor rails and the digital interface that facilitates communication between the modules and the host system. There are a number of PCBs inside the frame, all of which are connected to each other through cables and pins.


Both DC-DC converters use eight NXP PSMN2R2-30YLC FETs, while the common PWM controller is an ANPEC APW7159C. All of these parts are cooled by the frame's chassis.


The filtering caps are provided by Chemi-Con and Teapo. All of the electrolytic caps are Japanese, and they should, as such, last for a long time.


The VRMs are fed by the power modules through a couple of wires.


These two boards host the MCU (Microchip PIC24FJ32GA) and USB transceiver, a Silicon Labs CP2112 IC.