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 platform is the same as in the LEPA G1600-MA PSU, the MaxRevo, and high capacity Platimax units. The design is very clean, and still preforms well by today's standards, although already in production for some years. The primary side consists of a ZVS phase-shifted full-bridge topology, while the secondary side uses synchronous rectification to generate the +12V rail, with a pair of VRMs (Voltage Regulation Modules) to handle the minor voltages.


The AC receptacle incorporates a complete line filter (YO15T1, provided by Yunpen). The EMI/transient filter continues on the main PCB with three CM chokes, one X and four Y caps, and an MOV.


The single bridge rectifier is bolted to a dedicated heatsink, and its model number is GBU2006. It can handle up to 20 A of current, which is enough to cover this unit's requirements. The large PFC choke, or boost inductor, and the PFC input capacitor have been put behind the bridge.


The NTC thermistor that protects the unit from large inrush currents is well hidden by the APFC's heatsink. It is supported by an electromagnetic relay.


In the APFC, two SPW35N60C3 fets chop the incoming fully rectified signal; the three three bulk caps (400V, 330uF each or 990uF combined, 105°C, HC series, 2000h lifetime) with a rather small combined capacity for a 1.7 kW PSU are by Panasonic/Matsushita, so we expect a pretty low hold-up time. The APFC controller, an ICE2PCS01 IC, is on a vertical PCB. We also found an LM393 voltage comparator on the same PCB. On the main PCB is a CM02X IC that blocks the current through the cap discharge resistor when AC voltage is connected.


The main choppers are installed in a full bridge topology, and their model number is TK18A60V (Toshiba). On a small daughter-board resides a UCC28950 IC, the main switchers' controller, and the other IC on this board is a UCC27324, a high-speed, low-side power mosfet driver.


The main transformer looks small for the unit's capacity, but its high density should allow it to cope with the task.


The secondary heatsink holds eight IPP015N04N fets that regulate +12V. Two large toroidal chokes and ten Rubycon caps (16V, 1500μF, 105°C, ZLK series) behind these filter this rail.


The +12V rail is transferred to the modular PCB and the smaller PCB right behind it, with VRMs, through several bus bars. This particular approach manages to avoid the use of wires, which minimizes voltage drops, especially at high loads. The shunt resistors used by the OCP are soldered to the modular PCB's solder side. On front, to the left, is the protections IC, a PS238 that provides OCP for up to six +12V channels, and the unit comes with just as many virtual rails.


To restrict energy losses, both VRMs responsible for the minor rails are installed very close to the modular PCB, on a smaller PCB right behind it. Each VRM comes with an APW7073 PWM controller, and four APM2556N fets are used, while the filtering polymer caps are by Enesol.


A TOPSwitch-JX TOP265 integrated of-line switcher controls the 5VSB circuit, providing for high efficiency and minimal energy consumption in standby.


Soldering quality on the solder side of the double-sided PCB is very good. Right below where the +12V rails are rectified is a large copper plate to enhance the PCB's conductivity, which decreases voltage drops, especially with high currents.


The fan is by Adda, and its model number, ADN512UB-A90, tells us that it is a ball-bearing fan. It is rated for 0.44 A while operating at 12 VDC and is rather noisy at even low RPM, which makes it very loud once it speeds up.