Which PSU?

[scaryjim]

OK, if anyone hasn't been following the various threads I've complained about this in, here's a precis of my current situation:

Last week the proprietary PSU in my Antec Aria blew up. It didn't take the PC with it thankfully, but it did leave me without an HTPC. The replacement PSU - if I can even find one in stock - is very expensive.

I bought a 90W PicoPSU, but it would appear that it can't supply sufficient current to the 12V line to power up the computer. Fortunately I only bought it this week online, so I can return it under DSR, which is probably my best option.

That leaves me needing a PSU again. Looking around I could get a higher rated PicoPSU, but that'll be heading into the very expensive realms again, so I'm looking instead at 1U FlexATX PSUs which I believe I can successfully mod the case to use (without too much work).

I have a few options: there's a 120W unit which is fanless, which wouild be nice, but it's the most expensive, it doesn't have an ATX 12V connector and only supplies 8A on the 12V line (which should be enough, but...). Otherwise, there are 180W, 220W and 250W versions of the same PSU which all have a 40mm fan. The problem with that is that my case doesn't have suitable vents for it to draw air in or out (and I'd probably have to block the only fan mounting point to fit the PSU in, unless I got very creative), so they're far from optimal choices (on the other hand, they may be my only choice). The 250W is the cheapest @ £29.99 from microdirect, followed by the 180W @ £37 and the 220W at £43 - but the 220W is 80+ certified while the other two are not. The tempting thing to do is simply walk over to microdirect and pick up the 250W supply today, but given the low(ish) efficiency of it I can't help wondering if I'd be better buying one of the others (so I'm either closer to the rated power, or safe in the knowledge that it's a more efficient supply).

Or am I missing some other option?

Opinions Please


EDIT: One other thing that I might be able to do (although it definitely falls under the mad mod tag) is use a small 12V PSU I already have to provide additional 12V current to the ATX 12V connector - any opinions on how mad that is as a concept? It's got to bad news trying to use 2 different PSUs in one build, right...?

[Terbinator]

Do these have to be a certain size?

If they do have to be a certain size, I'm pretty sure BeQuiet do an ITX PSU.

Fanless would mean going Seasonic/Silverstone for normal ATX - also mean spending a lot of wonga.

[scaryjim]

Well, the original PSU is an odd one: it's kind of L-shaped. I haven't measured up the space it used to occupy, but basically it was a 120mm fan with a small PSU bolted to it, so it needs to be quite slim to fit in the space. I'll try to upload some pics of the inside of the case in a bit...

[kmac]

I think you've pretty much listed some well priced PSUs there. However, have a look at this Seasonic unit which got a good review in SilentPCReview

http://uk.rs-online.com/web/search/s...duct&R=5383940

Its small for ITX cases and 80+ efficiency. But at the higher end of your price specturm ( price quoted excludes VAT and is for 50 units, prices higher for 1 unit). The advantage is it has the ATX cables you will need, is 80+bronze, quiet, and made by a reputable company

I have one so can tell you how many and types of connectors etc.

[scaryjim]

Thanks, looks like a nice PSU. My only concern is that it's got a smallest dimension of 76.5mm, which might be too large for the case - I'll have to measure up when I get home!

... The advantage is it has the ATX cables you will need, is 80+bronze, quiet, and made by a reputable company

All the FlexATX ones I'm looking at are FSP, so I'm not too worried about the quality of them As I say, the main concern is the depth of PSU, as the Antec one was pretty slim. That and the fact that very few PSUs are designed to vent *out* of their largest side...

[watercooled]

What sort of components does the system have?
In answer to your earlier question, there are actually booster PSUs you can buy which fit into a 5.25" bay for example which are usually aimed at powering GPUs or something. And the Corsair HX1000 contains two separate switching PSUs. It's something you should probably avoid if possible but it might work, you should do some research into it first though; depending on how the motherboard is wired you might end up shorting a power supply if the circuits aren't isolated. I'd probably go for one of those 1U PSUs if a PicoPSU didn't have sufficient oomph.

[scaryjim]

It's a Sempron 140, ASUS M4A785TD-M EVO, 1x 2GB DDR3. There's also a PCI video in card in there at the moment. I've tried booting to BIOS without the HDD / DVD drive attached and it still won't make it. The 12V rail is rated to 5A, I don't know if that's peak or continuous but I'd guess the latter: don't know what the peak rating is.

I'm assuming that the PC very briefly runs at full load when it cold boots, and since the CPU can pull 45W I've only got 15W left over for everything else on the 12V rail before I'm beyond the current rating. Very silly of me to not think about it more carefully in the first place *doh*

The spare "PSU" I've got is a little thing from an ancient SFF PC someone gave me which only outputs 12V and 5VSB, and also has a PS-ON connector. It'll supply 5.5A on its 12V line, so I was considering wiring it up to a 4-pin connector and feeding the ATX 12v connector off that! Thing is that's never going to be a long term solution, so I guess I should forget it and just sort the RMA for the pico...

[scaryjim]

OK, measured up the PSU when I get home and was a little surprised to find that I could just about fit a flexATX PSU *inside* the old PSU casing, even with the 120mm fan in there! In fact, from the positioning of the PCB I wouldn't be at all surprised if the original PSU is actually a 1U flexATX in a custom chassis. This means 2 things:

a) I can actually look at much bigger PSUs that I previously though (~ 150x95x86mm)
b) I'm very tempted to buy the flexATX PSU and mod it into the original PSU chassis (after cleaning it, obviously ).

[watercooled]

I would have thought the same really (that the PicoPSU could run that system) but as you say the peak power draw might be too much. It could possibly be a faulty PicoPSU though, does it look like it's supplying power e.g. any LEDs on? My Athlon X2 5050e system only pulls about 90w max from the wall according to my power meter when it's loaded with Intel Burn Test though, 7zip only manages 75w (a more realistic max) so a 90w PSU could, in theory power that system. You've also tried without the HDD though, that would be another suspect i.e. high startup current.

[scaryjim]

Yeah, the pico is definitely supplying power on some lines: I get the standby LED on the mobo fine, and if I turn the PC on without the ATX 12V connector plugged in it fires up, the fans turn, the network lights blink - all that stuff (everything except POST, basically, which I assume is because the CPU isn't being supplied with current). I tried the same thing with a spare ATX PSU and got exactly the same result - no ATX 12V connector and everything fires up, fans spin, network lights blink etc. The only difference there was that the computer booted when I added the ATX 12V connector, which is what makes me assume that it's asking for too much juice on the 12V line.

[scaryjim]

Right, I've got an FSP 250W FlexATX PSU sitting on my desk Was pleasantly surprised to see an 80+ Bronze sticker on it when i picked it up. It doesn't look like I will just be able to transplant the guts into the old PSU chassis sadly, so now I've got to decide whether I mod the old chassis into a bracket for this PSU, or whether I just find somewhere else in the case to mount it. *sigh* this was meant to be an easy PSU replacement

[watercooled]

Check it works first! If it fits you could put it in the case sideways and use the front bit of metal from the broken PSU (would involve using a Dremel or something), popping out the AC socket and run the cable through that. You might want to use some electrical tape or something to cover the sharp edges in the hole so they don't strip the cable, also you should ensure a proper ground connection between the PSU and the case. I did something similar myself using a PicoPSU and the back of the PSU was supplied by a kind Hexus member to stop anything getting inside the case for example.

[scaryjim]

I'll have to do some pics to show you how the old PSU worked in the case - it was somewhat.... non standard

Having popped the flexATX open quickly it was obvious that I couldn't just transplant the guts, so when I got home tonight I had a quick look at how it compares to the old PSU and what the spacing round the case is like and I've come up with a plan that merely involves using parts of the old PSU casing to making a mounting bracket: so the new PSU will just screw into the bracket which will then fit back exactly where it used to be! It also means I get to keep the existing 120mm fan (although I may flip it round to be an intake rather than an exhaust). It also means I'll have a ready made bracket for 1U flexatx PSUs should the worst happen with this one (and it should mean I get to keep using my Aria for as long as they keep making microATX motherboards ).