A Look Inside

Before reading this page we strongly suggest to take a look at this article, which will help you understand the internal components of a PSU much better.


The OEM of this unit is Enermax and the used platform is similar to the Platimax 850W we reviewed in the past. This platform was originally used in Modu87+ units and then passed to Lepa G PSUs. Although it has been around for some years now, this design is still considered modern since an LLC converter is used in the primary side along with synchronous rectification on the secondary side and two DC-DC converters for the generation of the minor rails (5V & 3.3V). Of course the higher capacity Platimax units utilize a different and more advanced platform which however significantly raises the cost bar and since the Revolution87+ PSUs should stay at affordable price levels, the older Modu87+ platform along with some modifications was a better choice.


Right behind the AC receptacle there is a small PCB holding most of the transient filtering stage components. Namely four Y and two X caps are installed there along with two CM chokes. On the main PCB we find another CM choke and an MOV (Metal Oxide Varistor).


The bridge rectifier is cooled passively by a dedicated heatsink. Its model number is LL25XB60, it's a Japan made component and can handle up to 25A of current. Right in front of the bridge rectifier we find the PFC input capacitor and two current sense resistors.


In the APFC section two Toshiba K20J60U fets chop the incoming fully rectified signal and a C3D06060 boost diode is also utilized to protect from freewheeling currents. The two parallel hold up caps are provided by Nippon Chemi-Con (390μF each or 780μF combined capacity, 400V, 105°C, KMR series). Close to the aforementioned caps a thermistor is installed for protection against large inrush currents and an electromagnetic relay, which isolates the thermistor from the circuit once the start up phase finishes.


The PFC controller is installed on this small vertical PCB. It is a Champion CM6502S which according to its manufacturer is designed to meet 90+ spec (total efficiency) since it allows loss less (Zero Voltage) switching of the APFC fets.


As main choppers two SiHG20N50C fets are utilized.


In the secondary synchronous rectification is used so the +12V rail is generated by four IPP037N08N fets. Up to this point this is the only difference compared to the Enermax Platimax 850W which instead uses six IPP015N04N fets for the +12V regulation. The latter have much lower Rds(on) value meaning less energy dissipation and higher efficiency.


The minor rails are generated through two DC-DC converters. On each converter three fets (most likely APM2556 type) handle the regulation process along with their PWM controller. Also as you can see from the photos above, many polymer filtering caps are used along with some electrolytic ones. All are provided by Chemi-Con and in order to save some PCB space they are installed vertically on small daughter-boards.


The supervisor IC is a SITI PS232S which supports OCP for up to four +12V rails, matching this way the PSU's specs. It is installed on a vertical PCB which resides in the secondary side.


On the solder side of the small modular PCB we find two rather large Nippon caps which apparently were added at the last minute by hand, probably to improve ripple suppression. Many manufacturers discover that ripple is a little higher than desired during production, at which point they can't alter the main PCB design, so they add some extra caps on the modular panel to suppress these unwanted AC fluctuations on the DC outputs. As you can see soldering quality on this PCB is not exceptional.


On the main PCB soldering quality is vastly improved, compared to older Enermax PSUs we have seen and is on par with the Platimax's 850W. Nevertheless it still isn't so great compared to higher-capacity Platimax units or the MaxRevo PSUs which use a newer platform. In this side we spotted the LLC resonant controller, a Champion CM6901X IC. Also under the +12V islands we noticed four shunts, which along with the PS232S supervisor IC prove that indeed this PSU has four +12V virtual rails.


The cooling fan is provided by Enermax itself and its model number is EA142512M-0A (12V, 0.45A). Exactly the same is used in the Platimax 850W. According to Enermax its twisted bearing offers extended lifespan along with lower noise output. Indeed during our tests most of the time the fan was really quiet and only at higher loads/ambient it was making its presence felt.