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.


As with all ZX series PSUs the OEM of ZX 850W is Great Wall. This platform utilizes an older topology, rather an LLC resonant converter, to achieve Gold efficiency levels.


The first stage of the transient filter is located at the AC receptacle with one X and two Y capacitors. On the main PCB there are three coils, two X and two Y caps. Unfortunately the manufacturer omitted the essential MOV, something unacceptable for a high-end category PSU.


Two bridge rectifiers, US8K80R, are utilized and cooled passively by the primary heatsink. Right next to them resides a thermistor for inrush current protection and a relay that bypasses it once the PSU powers on and the PFC capacitors are charged. The APFC uses three STP25NM50N mosfets and a boost diode. There are two parallel CapXon (330µF, 420V, 105°C) smoothing/reservoir capacitors. As main switches two STP25NM50N are used. The combo PFC/PWM controller is a Champion CM6802.


In the secondary side four IPP034NE7N generate +12V and afterwards two DC-DC voltage regulation modules generate the minor rails. The 5V VRM uses two pairs of IPD040N03L and IPD060N03L mosfets. The other VRM, for 3.3V, is equipped by only two mosfets, an IPD040N03L and an IPD060N03L. The polymer capacitors on the VRMs are provided by Capxon and the electrolytic caps in the secondary side are provided by Teapo and are labeled at 105°C.


A huge large bus bar transfers +12V to the modular PCB. A highly effective way to transfer with minimal losses a large amount of power. A smaller bus bar grounds the modular PCB. Several RGTX series capacitors are used to further filter DC outputs. Strange enough purple wires, instead of red ones, are used for 5V and two ferrite beads are wrapped around them to suppress electrical noise.


In a vertical daughter-board the protections integrated circuit is housed, a PS223.


Soldering quality and workmanship on the main PCB is quite good but not top notch.


The fan is provided by Yate Loon Electronics and its model number is D14BH-12 (2800 RPM, 140 CFM, 48.5 dB).