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Old 05-29-2015, 07:32 PM   #2352
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Thumbs up ePower EP-350XP-24 (P022-E platform) (page 118)

Alright, today I decided to post something a little different from the usual HiPro and Macron PSUs:
ePower Xtrem-350 (model EP-350XP-24 based on P022-E platform).

Before I begin my "book", first I’d like to express my gratitude towards Pentium4 here, as he is the one that gave me this cool PSU.

Okay, now let's get down to brass tacks, the real deal, the actual PSU and its guts . Most of you PSU "maniacs" reading this thread know what I mean. Starting with some case pictures...
Nothing extraordinary here, but you can see that we have us a wire fan grille rather than cheap stamp cutouts in the case, so I think we are off to a good start. Also some sleeved and twisted output cables. And perhaps another notable feature is that some of the cables for the main rails on the ATX connector are 16 AWG rather than 18 AWG. So we are definitely NOT dealing with a cheapie "hong-kong-fly-appart LLC" PSU here .

What the label says…
Ah. It is a bit disappointing with all of those different wattages. It's like ePower really didn't want to print different labels for their PSUs, so they just did a "one-label-fits-all" here. But anyways, this is the 350W version, so that's what we'll be looking at…
Label claims two separate 12V rails capable of 18A each, but combined total is 20A, or 240W of power on the 12V rail alone. That should be plenty for a 90W TDP CPU and a medium-power graphics card, though. And one last bit of info we get from the label is who made this power supply. UL number E1390843 means this PSU was made by Topower.

Let's remove some screws now to see the guts…
Oh my! Did I just have a deja vu or something?... *drinks some cold water* Yep, that is a double warranty sticker . But I don't think I can get double the warranty here .

Anyways… Moving onto the real guts. Top view:

We see four transformers here (the one on the upper right is a CM choke for the AC line). Definitely quite unique design, as you will see in a bit (at least nothing that I have seen before). It's basically a half-bridge PSU with an extra transformer that seems to be used for over-power protection/sensing (OPP). As for the sizes, the main traffo appears slightly bigger than your typical "35". I think it is a "39"-size.
Other things to note: there is an actual AC connector on the board and the fuse has its own holder. The switch on the back of the PSU is a DPST. All mains-wiring is 18 AWG rated for 600V. And, of course, nice, big, black heatsinks .

Here are a few more internal shots:

And finally, a solder-side and fan picture – all for your viewing pleasure .
The soldering is quite good on this PSU and the board was cleaned very well from leftover flux. Also, note the fan: although it is a sleeve bearing Globe Fan, it has a much bigger rotor assembly and the plastic is shiny, smooth, and well-formed. The fan also spins very "smoothly". So I think this is definitely a higher quality Globe Fan. Plus, it is temperature controlled, and the controller itself actually has connectors for two addition fans. Cool!

Now, these pictures still can't really tell you how unique this PSU is, so I will do a detailed breakdown of the components next.

Primary Side
2x single-mode chokes on AC receptacle + 1x CM choke
1x 0.33 uF + 1x 0.1 uF safety X-caps between L-N. Also 5x Y-safety caps.
GBU8J bridge rectifier (8A, 600V) and has its own small heatsink.
2x Teapo LXK 200 V, 680 uF primary bulk caps, 21 x 44 mm (d x h)
2x 2SC2625 NPN BJTs for the main PS + 2.2 uF film cap
2x YihCon RK 50 V, 4.7 uF caps for the BJT base drive
1x 2SK2645 N-Ch MOSFET for the 5VSB

Controllers and ICs
This is where it gets interesting. There is a UC3842b PWM controller. However, this is not for the main PS – it is for the 5VSB. Yes, a whole PWM controller just for the 5VSB! Why Topower didn't use a PWM-FET combined IC? I don't know either. But this is still much more enlightening than a 2-transistor design. As for the main PS, that uses a standard TL494 controller in conjunction with a LM339N quad comparator.
The 3.3V rail does not appear to be linear or mag-amp regulated like you might expect. Instead, it is (I think) a single-ended DC-DC buck-converter (high-side MOSFET + free wheeling diode + output coil), with its source being the 5V rail. Now, what I am not sure about is what controls this. There is a KEL321 chip on the board from ST micro (which I ASSume is equivalent to a TL321 dual op-amp and is what drives the 3.3V rail MOSFET). Finally, the -5V rail (yes, there is one on this PSU) uses a 7905 IC and it is attached to the secondary heatsink.

Secondary Side
2x D83-004 (30A, 40V) schottky rectifiers in parallel, 100 Ohm load resistor
2x Teapo SC 6.3 V, 3300 uF, 10 x 25 mm (d x h) caps with 3-turn, 6 mm PI coil in between them.
1x Fuhjyyu TMR 10 V, 2200 uF, 10 x 25 mm, with a 5-turn, 6mm coil separating it from the 5V rail. This is the connected to the (upper) MOSFET for the 3.3V rail buck regulator.

3.3V RAIL:
No rectifier (shared capacity of the two D83-004 on the 5V rail), 100 Ohm load resistor
CEP8030 or CEP8060 MOSFET for the buck regulator (not sure of label, since I could see only the letters in bold.
SBL2040CT free-wheeling diode for the buck regulator
2x Fuhjyyu TMR 10 V, 2200 uF, 10 x 25 mm (output of buck regulator), with 6-turn, 5 mm air-core PI coil in between these caps

2x BYQ28E fast recovery rectifiers (10A peak per diode, 200V) in parallel
330 Ohm load resistor
1x Fuhjyyu TMR 16 V, 2200 uF, 10 x 30 mm, with 18-turn, 6 mm PI coil before it

-12V RAIL:
Two 2 A (?) diodes, 220 Ohm load resistor
1x YihCon RK 16 V, 220 uF, 6.3 x 11 mm and 1x Fuhjyyu TNR 16 V, 470 uF, 8 x 13 mm
With ~36-turn, 4-5 mm PI coil after the YihCon cap above.

Can't see what rectifiers it has… 560 Ohm load resistor
7905 linear regulator
1x 1x Fuhjyyu TNR 16 V, 470 uF, 8 x 13 mm after the regulator

SB540 (?) (5A?) schottky rectifier, 220 Ohm load resistor
2x Fuhjyyu TNR 10 V, 1000 uF (?) caps with a PI coil in between them

Finally, I did some brief 5VSB tests.
- With no load on 5VSB, the PSU pulls 3.1W from the wall @ 0.42 PF and sits at 5.06V
- With 1.1A load ( ~5.5W) on 5VSB , the PSU draws 10.3W @ 0.51 PF and is exactly 5.00V. The efficiency is about 53% with that load, which is quite acceptable compared to many other PSUs I've seen (especially some 2-transistor designs).

And that concludes my unofficial review of this thing. I still haven't decided in which one of my future build PCs I'll put it yet (I have several socket 939 and P4 motherboards sitting around). Not sure if I will recap it yet either, since it is NEW! Generally, for my own stuff, my rule is: no Fuhjyyu cap gets a break until it bulges, leaks, or goes high-ESR. So I might just use it as-is for a while.

Anyways... as always, big thank you if you read through my wall-of-text . (and again if you didn't )
Attached Images
File Type: jpg ePower EP-350XP-24 (5).jpg (73.0 KB, 21 views)
File Type: jpg ePower EP-350XP-24 (6).jpg (114.3 KB, 19 views)
File Type: jpg ePower EP-350XP-24 (7).jpg (199.9 KB, 28 views)
File Type: jpg ePower EP-350XP-24 (8).jpg (73.0 KB, 27 views)
File Type: jpg ePower EP-350XP-24 (9).jpg (295.0 KB, 237 views)
File Type: jpg ePower EP-350XP-24 (10).jpg (279.6 KB, 34 views)
File Type: jpg ePower EP-350XP-24 (11).jpg (130.4 KB, 38 views)
File Type: jpg ePower EP-350XP-24 (15).jpg (247.2 KB, 167 views)
File Type: jpg ePower EP-350XP-24 (14).jpg (381.4 KB, 23 views)
File Type: jpg ePower EP-350XP-24 (18).jpg (88.6 KB, 25 views)

Last edited by momaka; 05-29-2015 at 07:39 PM..
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