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!


As we already mentioned, the OEM of this unit is Delta Electronics. The PCB is clearly underpopulated and single-sided to keep costs down. The design is not modern but this is a mainstream PSU, and the secondary side utilizes a group regulated scheme to generate the minor rails. Also, only passive components rectify the DC outputs because mosfets would increase the cost significantly.


The first part of the transient filter is right at the AC receptacle. It only consists of a pair of Y caps. The main PCB holds the second part of the aforementioned filter. It consists of four Y caps, two X ones, and two CM chokes. Delta unfortunately didn't use an MOV (Metal Oxide Varistor), which we find unacceptable.


The single bridge rectifier, a US8K80R, is bolted onto a dedicated heatsink. It can handle up to 8 A of current, so it will suffice for the needs of the VP550F.


In the APFC section, a single Infineon IPW60R160C6 mosfet is used along with the necessary boost diode. The hold-up cap is a Samxon. Labelled at 85°C, it is rated at 450 V with 330 μF capacitance. We would like to see a higher quality cap used here.


Two Infineon IPP60R190E6 are used as main switchers.


The combo PFC / PWM controller is an outdated Fairchild FAN4800A IC that is soldered onto the main PCB. Also, the standby PWM controller is a TNY278PN that can deliver up to 16W at 5VSB with 230VAC input.


Only passive components are used in the secondary side. Active ones are more expensive but offer much higher efficiency. So, the +12V rail is handled by a couple of STPS40M60CT Schottky Barrier Rectifiers (SBRs). Two STPS30L30CT SBRs generate the 5V rail, and a single STPS30L30CT generates the 3.3 V rail. We also spotted the SBR that rectifies the 5VSB, an SB1060FCT, in the secondary side. The only two toroidal chokes in the secondary side point to a group regulation scheme (where +12V and 5V are regulated by the same circuit and 3.3V by another). This means that the unit won't handle highly unbalanced loads amongst rails optimally. Finally, the filtering capacitors that Delta used are mostly provided by Ltec, so they are not the best ones available, but we also found two Rubycons, two Chemi-Cons, one electrolytic, and one polymer. Finding such good caps in even low quantities inside an entry-level PSU is really weird but nice.


The protections IC is a DWA106 that is supported by an LM393N dual-voltage comparator. The latter most likely handles the OCP (Over Current Protection) for the two +12V rails.


Soldering quality may not be up to the levels that the high-end Delta implementations enjoy but is still really good, especially for a budget product.


The PSU really has two +12V rails, with the shunt resistors located on the component side of the PCB.


The cooling fan is provided by Yate Loon Electronics and its model number is D12SH-12. it isn't quiet with a maximum speed of 2200 RPM and 40 dBA noise output, but its maximum speed is thankfully curtailed by the fan-control circuit. Also, it uses a sleeve bearing to drop its price while aggravating its lifetime. However, we didn't expect to find a ball-bearings fan (or an FDB one) in a budget unit.