Fan Control for Server PSU (Delta DPS-350AB-12 A 350W 80 Plus Silver)?

PVC

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I received this Flex-ATX Delta DPS-350AB-12 A 350W 80 Plus Silver PSU, and did some preliminary testing for trying to evaluate noise levels of the 15x40 mm PSU fan. My test platform is an APU-Build/InWin Chopin/ASRock B450/Ryzen5-3400G/150W-PSU with the Chopin-150W-PSU unplugged and the Delta-350W plugged in its place. The 350W-PSU-fan starts with a howl at full speed each time the AC/wall-power is disconnected and then slows for a moment and then forever shuts off after the initial burst of fan speed.

  • The PSU-fan starts with a howl at full speed each time the AC/wall-power is disconnected
  • After the initial full fan speed startup the fan shuts off completely
  • The fan remains shutoff for subsequent startups unless the AC/wall-power is disconnected again
  • The PSU was only mildly warm when touched with your hand, but after my normal use for an hour or so it is more than mildly warm but still not hot.

The cable from the 15x40 mm fan is a 3-pin cable (Red, Black, Blue) that plugs into a 3-pin fan receptacle on the PSU-PCB/Printed-Circuit-Board (see pictures). So I am guessing that this PSU has its own built-in fan speed control?

Maybe the PSU is just not hot enough to require the fan? I tried a mild stress test using Asus RealBench to heat-up the 3400G-CPU to 75c. If the fan only needs to run at slow speeds (OR OFF) for my APU-Build then that would be great!! I wouldn't even consider doing a fan mod for excess fan noise. But I don't know for sure if that is the situation? Maybe I need to try heating it up with a Prime95 stress?

Anyone have experience with these server PSUs? Is fan shutoff normal for my APU-Build?
 
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PVC

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I could try using ASRock motherboard fan control by:
  1. unplugging the 3-pin Delta fan from the receptacle on the PSU-PCB/Printed-Circuit-Board
  2. plugging the 3-pin Delta fan into my Noctua Extension cable
  3. Connect the extension to ASRock Chassis Fan 2 in order to get motherboard fan control

Maybe set fan to DC-MODE with the Noctua low noise adapter/LNA inline to accomplish running the PSU fan at a constant low speed. Or, maybe set fan to PWM based on CPU temperature. eta> Oh, I don't need the low noise adpter/LNA because I can lower the speed by changing the DC MODE control from FULL SPEED TO STANDARD.
 
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PVC

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That is one kick-azz fan. Check out the 11000 RPM and Air Flow;
Delta Fan 15x40 mm - AFB0412SHB DC 12V 0.35A
  • Air Flow 14.8 CFM (0.414m³/min)
  • Static Pressure 0.601 in H2O (149.7 Pa)
  • Noise 41.5dB(A)
  • RPM 11000 RPM
  • Power (Watts) 1.92 W

Tomorrow I will do some more testing;
  1. First to see is the PSU will function with the Fan unplugged from the PSU-PCB
  2. Second to see if I can use a 3-pin extension cable to connect this Delta fan directly to motherboard control
 
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REVOCCASES

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some of these server PSUs have a pretty clever control circuit to check if the fan is connected and working (therefore the fan is turned on to 100% when you plug it in, so the PSU can detect if the fan is working normally).

if you disconnect the fan or replace it with another model you could run into the issue that the PSU will go into "failsafe mode" because it "thinks" that the fan is broken.

from what I read in your first post this sounds totally normal. at some point the fan should kick in when the PSU gets too hot. just run a stress test for a bit longer and see what happens.
 

PVC

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Thanks for that; Yep, with the 3-pin fan unplugged from the PSU-PCB it only runs for about 8 seconds;
  • The motherboard did get temporary power to show lights and spin the CPU cooler
  • After 8 seconds or so the PSU shuts down forever
  • You cannot power on the computer again unless you unplug and re-plug the wall power
  • If you unplug and re-plug the wall power then you can get another 8 seconds of power from the PSU

I plugged the PSU-Fan back into the PSU-PCB and the computer works again with the fan still off. I will try a Prime95 stress test to get it warmed up in order to evaluate the fan sound.
 

PVC

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Success: The fan came on right away with Prime95 stress test. I am guessing that Prime95 draws more power. I cannot hear the PSU fan at all. But if I put a wet finger next to the exhaust I can feel the Air Flow. Or if I put a butane lighter flame next to the Air Flow (being careful not to burn anything) then I can see the Air Flow effects on the flame.

This is great because I cannot hear the PSU fan!! My Noctua NH-L9a CPU Cooler fan makes much more noise than the PSU fan and I never hear the Noctua unless I am stress testing.

Caveat; Repeat - this is a low power APU build, no gaming. My regular PSU is the Inwin Chopin 150W PSU.

So Far, so good. I don't have my K39 case yet to see how the PSU fits. Not bad for $26 free shipping.
 
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PVC

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Moving on to cable management; There are only two cables (listed below) that I need for my APU Build. Also, that tiny 4-pin P3-cable may be for a CD-drive or floppy??? I dunno. I don't need the P3 connector but I will keep it because it is (too complicated and too miniaturized) to remove. Here's the two cables I need:
  • 24-pin ATX power
  • 8-pin EPS motherboard power

The other cables for Graphics card power, Sata power, and the obsolete P8 connector will be snipped and capped with terminator caps crimped on to the end of each of five wires.
 

PVC

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I got my K39 case in today. The Flex-ATX 350W PSU fits nicely/snugly into the bottom of the K39 case secured by 2 screws.

Thanks and a big shout out to @REVOCCASES for the inspiration that led me to this (practical/common-sense) and (cheap-$26 wow!) recycled Server Flex-ATX power supply for my APU build(s).

eta: Speaking of Cable Management; the above picture shows cables routed to left in the picture. I will change that to route the cables to the right of the picture so that they are hidden (behind the motherboard) into the vacant Graphics card space. Then I need to remove the motherboard mounting tray to route the cables again to the front for plugging into the motherboard. The reason for removing the tray is because the plugs are too big to route through that little slot between the tray and the side of the case. eta: Whoops; changed my mind on routing cables behind the motherboard. The PSU cables are heavy gauge and difficult to bend.
 
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PVC

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I switched to using heat shrink tubing to cap off the 5-wires that were cut in order to remove the unneeded Sata and PCIe power from my recycled Server Flex-ATX PSU for an APU/no GPU build.
  1. In preparation, the wires were cut at varying lengths to avoid termination all at the same length.
  2. A tiny piece of heat shrink tubing (about 12mm long) was applied to the cut wire and overhanging the end by 5mm. The tubing size was large enough to fit snugly over the wire without excess/sloppy diameter. This was heated and pinched to seal the 5mm overhanging end.
  3. Three of the small wires with heat-shrink-terminated-ends were placed into a larger heat shrink tubing and two other shorter wires (not shown in the image below) into a separate larger tube. The second layer of larger heat shrink tubing was heated to apply and also had pinched/sealed overlap at the end.


The tiny unused P3 connector (in the background of the above picture) was wrapped up along with the terminated cables using electrical tape, leaving only two cables that I need for this APU/no GPU build;
  • 24-pin ATX power
  • 8-pin EPS motherboard power

 
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