The 2012 El-cheapo PSU Roundup

[c_hegge]

Well, I'll be darned. Fixed.

[LongRunner]

In test 4 for the Coodmax you stated 3.33V on the +12V rail.

[c_hegge]

And I thought I had bad voltage regulation from some of this year's contenders

Jokes aside, I have fixed it

[LongRunner]

I have a bottom-of-the-barrel CWT build labelled as "Psi" brand, model ATX-400EPNC12. Quality-wise it's about level with the Epic Fail ATX-400, though the PCB is clearly different (the same one used for the "ISO" series).

The mains wires to the PCB are only rated for 300V (AWM 1007, the same style used for most output wires). I don't know if this is a serious hazard, but the mains cords I've cut open have heavier insulation, and decent PSUs usually use 600V (various styles, some of which are double-insulated) wiring on the primary side. The input filtering includes three 400VDC film capacitors (a 0.68µF on the AC input, before the switch, and two 0.1µF on the PCB), one common-mode coil, and three 4.7nF 2kV ceramic capacitors (two on the AC side, one on the DC side of the bridge). The rectifier is made up of four RL205 (2A 600V), the primary capacitors are 330µF "MK" (which look much like Fuhjyyus, right down to the date-code format, so presumably they're another rebrand of them), and the main switchers are TT2146. The main transformer is EI-28 . The +5VSB has two 680µF 10V 8mm Fuhjyyu TMR, the +3.3V (the only other rail with a full Π filter) has a 1000µF 10V TN before the coil and a (leaking) 2200µF 6.3V TNR (a special orange type which seem to be commonly used on the +3.3V in ISO series PSUs) after (both 10mm), the +5V has two 470µF 10V 8mm TNs, and the +12V has a single 680µF 16V 8mm TMR.

The fan is a Ruilian Science RDM8025SA, the same model in the Okia from the previous round-up. I only just found out how much more noise can result when you put a fan in a badly ventilated PSU, and it can make seemingly very quiet fans ~whooooosh~. I bet this PSU would get another fail award if you reviewed it.

By the way, the Epic Fail has no MOVs.

[c_hegge]

I have a PSI branded unit which I'm doing in this year's roundup. It is a Solytech. It did at least 250W (I think. I haven't got its results in front of me now) in spec, and shut down when I asked for more.

[LongRunner]

On the page for the Aywun:

Can’t deliver anything with the ripple in spec, No input filtering, Inefficient, Poor ripple suppression...

And on the Epic Fail's page...

Can’t deliver anything with the ripple in spec, Shuts off above 250W, Inefficient, No SATA connectors, Poor ripple suppression...

For some reason, the wires between the inlet, switch, and pass-through, including the earth wires, on both the Epic Fail and my Psi are 600V (AWM 1015, which is single-insulated), even though the wires from there to the PCB are only 300V. Beats me what CWT were thinking.

[LongRunner]

Regarding the Rexpower...

The Ripple suppression was also average. Yes, it was acceptable, but it was unspectacular on the 12V rail.

That's probably because they only used the single cap there. Using two caps, one on each side of the ferrite coil, would likely give a big improvement. The +5V rail in that unit actually gave good results so it seems to me that the +12V wouldn't be hard to improve - they just don't want to improve it.

I know Fuhjyyu are awful, but I'm not sure they're any worse than the other brands featured in that unit.

[c_hegge]

Regarding the Rexpower...

The Ripple suppression was also average. Yes, it was acceptable, but it was unspectacular on the 12V rail.

That's probably because they only used the single cap there. Using two caps, one on each side of the ferrite coil, would likely give a big improvement. The +5V rail in that unit actually gave good results so it seems to me that the +12V wouldn't be hard to improve - they just don't want to improve it.

I know. I just don't comment on why or what could be done to improve it in that part of the review. If I do so at all, it's in the build quality discussion.

I know Fuhjyyu are awful, but I'm not sure they're any worse than the other brands featured in that unit.

I am. I still see more failed fuhjyyu caps than any of those no-name brands (CS/12KJ included).