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 OEM of this unit is HEC/Compucase, and an older design and components were used to keep production cost low, which lowers the final price of the product by as much as possible. The unit then uses passive components for the rectification of all rails in the secondary side and a group regulation scheme, which bodes badly for our cross load tests.


We removed the unit's main transformer and some other components to provide you with a clear view of its internals.


A small PCB behind the AC receptacle houses the first part of the transient filter including one X and two Y caps along with a CM choke. The second part of the above filter is installed on the main PCB and consists of one CM choke, two Y caps, a single X cap, and an MOV (Metal Oxide Varistor). We should remind you here that the latter is a very important component since it provides protection against surges coming from the mains network.


A couple of bridge rectifiers with model number GBU1006 are bolted to a dedicated heatsink.


In the APFC, three FDP18N50 fets and a BYC10-600 boost diode are used, and the hold-up cap is provided by Teapo (400 V, 330 µF, 85°C). We would like to see a cap with higher capacity and a better temperature rating here instead.


The main switchers are two FDP18N50 fets and the combo PFC/PWM controller is a Champion CM6800TX IC. The latter is installed on a vertical daughter-board.


The standby PWM controller is a Power Integrations TNY279PN IC.


The +12V rail is generated by four PFR30L60CT SBRs while the 5V rail is rectified by two STPS30L45CTs; the 3.3V rail is handled by another pair of STPS30L45CTs.


All caps in the secondary side are provided by Teapo and are rated at 105°C. Teapo caps are among the best non-Japanese caps, so all is good here.


There are only two chokes in the secondary side, which will severely hamper the unit's performance, especially with highly unbalanced loads on the rails. Two chokes in the secondary side are a clear indication of a group regulation scheme, where the +12V and 5V rails are generated by the same circuit and use the same choke while 3.3V is rectified by a second circuit utilizing the smaller of the two chokes.


The protections IC, a Weltrend WT7527 IC, supports OCP for up to two +12V rails. It is soldered to the component side of the main PCB.


Soldering quality is good, especially for this price category.


The fan has HEC's logo, and its model number is EFS-12E12H (12 V, 0.25 A). Exactly the same fan is used in the EVGA 500B, and although it isn't the quietest available, the controller keeps its rotational speeds low during normal conditions and low- to mid-range loads; so it doesn't produce a lot of noise. The letter "S" in EFS probably stands for "sleeve bearing".