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 better.


Silverstone trusted Seventeam, an OEM we have encountered before, with the construction of this PSU. The main PCB is really long and houses two extra-large heatsinks. A full-bridge topology is utilized on the primary side, and we find a synchronous rectification scheme for the +12V rail with two DC-DC converters for the generation of the minor rails on the secondary side. The manufacturing quality looks good, although it is not top notch, and the secondary side mostly uses polymer caps for ripple filtering.


Behind the AC receptacle is a small PCB that holds a pretty long mains fuse, a CM choke, two Y caps, and a single X cap. Thankfully, the power wires are connected with the main PCB through spade terminals, so their removal is a piece of cake and no de-soldering is needed. On the main PCB, we find the other components of the transient fiter: two CM chokes, an X cap, two Y caps, and an MOV.


The two parallel bridge-rectifiers are bolted onto a small heatsink, and their model number is GBJ2506. Each one can handle up to 25 A of current, so they are pretty strong.


We find an electromagnetic relay and the thermistor that suppresses high inrush-currents behind the PFC input capacitor, which filters the high-frequency ripple of the bridge-rectifier output. Above and next to it are two chokes which, together, form the main APFC choke. There was apparently no space for a larger choke so two smaller ones had to be used in series. The hold-up caps are provided by Hitachi (560 μF each or 1120 μF combined, 400V, 105°C) and the APFC controller is a UCC3818D IC.


In the APFC, four Infineon SPA20N60C3 fets are used with two IDH08SG60C boost diodes made by the same manufacturer.


The main switchers are four SPW35N60C3 fets arranged into a full-bridge topology. Their PWM controller is installed on a small vertical daughter-board, and, unfortunately, several components blocked the view, which made identifying its model number impossible.


On the secondary side, six IPP032N06N3 rectify the +12V output that feeds two DC-DC converters generating the minor rails.


Filtering on the +12V rail is mostly done by polymer caps of the Lelon brand. We find two pairs of Enesol and APAQ polymer caps on each one of the DC-DC converters.


The 5VSB circuit features a PI or capacitor-input filter consisting of two caps and one inductor to suppress AC ripple.


This vertical PCB houses the supervisor IC: a SITI PS232S that provides OCP for up to four +12V rails. Nevertheless, we strongly believe that this IC doesn't handle the OCP of the +12V rails at all, and you will see on what grounds we base this claim in one of the paragraphs below.


Some heat-shrink tubing on these naked wires would be nice.


Many thick wires transfer earth and all the outputs to the modular PCB. Soldering quality on the modular PCB isn't that good.


On the front of the modular PCB is a WT7518D supervisor IC that supports OCP for up to four rails. A LM393N dual voltage comparator next to it provides two additional OCP channels, which increases the total number of OCP channels to six; the same number as the +12V virtual rails that this PSU has in multi-rail mode. Seventeam apparently didn't want to transfer the signal of the switch that toggles between the single rail and the multi-rail modes all the way back to the vertical PCB holding the main supervisor IC, so they installed a smaller supervisor IC and an LM393N directly onto the modular PCB to be used exclusively for the OCP circuit. We find many polymer filtering caps on the front of the modular PCB. All of them are provided by APAQ and Enesol. APAQ and Enesol also provided the three pots/potentiometers used for adjusting the voltage of the major rails, and the switch that disables OCP and converts the unit into a single +12V rail.


Soldering quality on the main PCB is, generally, good, although there are some blobby solder-joints, which are clearly handmade, on the secondary side.


The cooling fan is provided by Sunon and its model number is PF80251B3-0000-A99 (12 V, 2.7 W, 53 CFM, 4200 RPM). It uses double ball-bearings for increased lifetime and is quite noisy, especially at higher speeds. We have to wonder why Silverstone hasn't kept the top-mounted fan that their original ST-1400PSZ uses instead of installing this "noise generator" into the ZM1350.