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.


Once we removed the casing we identified the OEM, which is Channel Well Technology (CWT) and to be more specific the PSU is based on CWT's DSG platform.


The first part of the EMI/transient filtering side resides on the AC receptacle with two Y and one X capacitor. It continues on the main PCB with four Y and one X capacitor, three coils and an MOV.


There are two bridge rectifiers cooled passively by heatsinks. Right in front of the bridges, on a vertical daughter-board we find the combo PFC/PWM controller, an CM6802. In the APFC two 20N60C3 mosfets are used and of course a boost diode. The smoothing/reservoir capacitor is a Nippon Chemi-Con (85°C, 560μF, 400V). Two FDP20N50 mosfets are the primary switches.


In the secondary side synchronous design is used, meaning that more efficienct mosfets are used instead of Schottky Barrier Rectifiers (SBRs) that register forward voltage drops. Five IPP037N08N3 mosfets handle +12V and afterwards the minor rails are generated via two DC-DC voltage regulators from +12V. In each voltage regulator module we find an APW7073 controller and two pairs of ME70Ν03 and ME90N03 mosfets. All filtering capacitors in the secondary are from Chemi-Con and besides electrolytic we also found two polymer ones. The protections IC is a PS229.


The modular PCB, although it has space on its solder side for some capacitors, is not equipped with any. Shame because that would greatly help ripple suppression. Soldering quality is good enough here.


The solder side of the main PCB exhibits many bad, hand made, solder joints. Way too much solder was used in many of them and in general we can pretty much say that soldering quality and workmanship are average.


We spotted some weird cable joints near the area where the DC outputs leave the main PCB. As it seems there wasn't enough space on the main PCB for all 5V and 3.3V wires so cable joints were made to feed the extra connectors. The bad thing is that whoever made these joints left the soldering iron on the 3.3V cables so it nearly melted them and on top of that the joints are far from good. Also the heatshrink on one of them is loose enough to slip and provoke a short circuit, if the naked cable touches the casing. We suspect that the sample we have on our hands is a pre-production model because it's the first time we see such low quality from CWT. I previously tested many CWT PSUs and have never seen such an issue before.


The cooling fan is provided by Yate Loon Electronics (D14SM-12, 1400RPM, 62CFM, 29dBA).