HTPC PSU fan mod

[watercooled]

After carefully choosing quiet components for my general PC, there is still an annoying buzzing noise coming from the PSU, but being a SFF one, its not as simple as just swapping it out for another. So, I got into warranty-voiding mode and cracked it open.



First thing, if you've ever opened up a well-used power supply you'll be wondering why it's not caked in dust. Well it was but it turns out those air-bed pumps, like this, but the one I use is rechargeable, are fantastic for dusting (do it outside, of course).

I checked the fan on my bench PSU to make sure it was the source of noise, it sounds like bearing noise, and you can hear it even at low RPM. It's a 15mm depth fan so I don't have a huge choice; I had considered mounting something on the outside of the case but there's not much room because of the CPU cooler. So, I've gone for one of these and I'll either bodge the connector on to the existing 2-pin connector in the PSU, or drill a hole in the case and connect it to the motherboard.

[watercooled]

In hindsight, it's probably not the most interesting thing I could have posted, but you got some PSU internal pics.

Besides, I wanted to point the potential problems with obscure PSU form factors and recommend those pumps for dusting - they're cheaper than using air dusters/air compressors and as you can see they have pretty much the same effect. Also better than using a hoover as you don't need to go poking around to pick up the dust.

Oh and I should mention, never open up a power supply if you don't know exactly what you're doing a) because you'll void your warranty and B) depending on the design (i.e. some may drain the caps, deliberately or otherwise, when unplugged, but never count on that - always assume they're charged to operating voltage), those huge input filter caps can potentially store enough of a charge to kill if you short them with a part of your body.

[GoNz0]

fit a variable speed fan adjuster while your at it.

i did that years ago on a psu i had, saves you taking it apart again

[watercooled]

Good idea, in fact I might also connect the case fan to it.

[Golden Dragoon]

What sfx psu is that, I have been thinking about ripping the fan out of mine and replacing it with an akasa amber or something like that, but they are 25mm fans, so would have to dremmel out the fan grill, and use spacers so only ~10mm of the fan is sitting outside the psu, with the rest inside it.

Edit: you shouldn't need to bodge the fan connector to keep it internal, just use a saftey pin or small screwdriver to remover the ends of the wires from the 3 pin, and then slide them into the 2 pin connector from the old fan, and connect them up, when I have done this in the past it has worked perfectly.

[watercooled]

It's an Antec MT-350 supplied with the Antec Minuet case: http://www.anandtech.com/show/2637/4

Yeah Akasa amber are good fans, but I can let you know what that Sanyo one is like when I eventually get it so you can avoid any major modding, unless you're OK with.

Thanks for the tip about the fan connector, I was planning on breaking the side off the socket but that would be a tidier + reversible way of doing it.

[PeterStoba]

You can also get cables to do the job very nicely - http://www.amazon.co.uk/gp/product/B...00_i00_details

[watercooled]

You can also get cables to do the job very nicely - http://www.amazon.co.uk/gp/product/B...00_i00_details

Why make it too easy?

And hi BTW, not seen you for a while!

[Bambooz]

So you replaced a 30cfm fan with a 20cfm fan, and someone already suggested a fan controller to make it even slower? I smell roasted PSUs already..

Connecting it to the original PSU fan wires would be best, as it's temperature regulated according to the PSU temperature, not CPU or whatever the mainboard checks.
Getting rid of the stamped fan grille on the PSU cover might also help with the noise.

[watercooled]

MFR quoted CFM ratings are mostly rubbish, also at quoted max speed, but the current fan will never get to max speed - I tried it on a bench power supply at 12v and it's horrendously noisy. The PSU is hardly loaded in my rig so only needs minimal airflow, in fact it would probably be fine passive, but I want to keep some air moving over it to be safe. The fan only speeds up at about 150w load, the system it's powering isn't capable of pulling that, so it's constantly at minimum speed anyway, but the bearing noise is annoying in an otherwise very quiet PC.

The variable speed fan controller would just give me manual control over the speed.

The fan grill is integral to the case, and I want to avoid bodging things if necessary, and like I say it's bearing noise rather than airflow noise that's audible.

[wasabi]

What is the power draw of your htpc? If under 90w you could ditch the old psu entirely and fit a pico-psu or the likes.

I used to do fan replacments regularly before I went fanless. Thinking about it there is no good reason manufacturers can't make the fan a truly end-user replaceable part like case fans

[watercooled]

The most I can get is about 75 from the wall at full load, so a PicoPSU would be a possibility. However, the FSP one I have has a noisy (coil whine) power brick and I'm not keen on the big hole at the back of the case after removing the original PSU, but that's mostly nitpicking. Something else which concerns me is how hot the internal part gets without forced airflow, the components reach ~70C powering a D510MO Atom board, I'm not sure if the 'official' PicoPSUs are any better?

The new fan is already on its way so I'll see what that's like, as the power supply itself is very good, and it's cheaper than a new PSU.

[wasabi]

The DC board I've got isn't a pico-PSU but a similar idea gizmo, can't remember the brand to be honest but it comes on a little PCB like pic below:

the fact the power brick is eternal to the case isn't a bad thing IMO - it keeps the heat from the PSU external the case, even though I dislike the mess of power bricks as a point of principle.

I'm not too fussed about appearance of the machine as you can see - it is hacked into an old Shuttle and sits hidden behind the TV beside the sub.

[Golden Dragoon]

Took the dremel to mine last night and removed the rough stamped steel grill, and then popped it back together, it has made a big difference, the sound is just as loud, but less turbulent and much more pleasant, I will still replace the yate loon it came with though, am just waiting on the akasa to get here.

Also I have to say that I don't think my CiT psu, is a CiT psu, the caps are all japanese and rated at 105C the heatsinks inside are of a very good quality, and the soldering is all very good, it is made down to a price though with only passive pfc, but seems a whole load better quality than another CiT atx psu I took apart.
My guess is, they don't make sfx psu's and just stick a label on someone elses, or they were having a very good week\month when they made mine.

[watercooled]

It's bearing noise rather than air turbulence for me so I doubt it would make much of a difference on mine. Still waiting for the fan.

PPFC doesn't imply poor quality, it could just be an older model - maybe they bought old stock from another MFR? You can often get an idea of the OEM from the guts - you'll often get a brand printed on either the main transformer or the PCB but you can get a good idea based on layout alone. I'm thinking possibly Delta, but pics may help. Also, do the guts look similar to mine, as that Seasonic platform is rebranded and sold by a few MFRs.

[Golden Dragoon]

When I whip it out again to do the transplant I will take some pics, though the heatsinks look similar to some fsp ones in an old power supply I had, they are an upside down J with long oval holes punched through them, and are quite thick and look good quality, the only other CiT psu I have ever seen has simply had a couple of rectangular bits of aluminium with sharp edges and no fins or holes cut into them at all.