Replace noisy power supply fan in HP Proliant Gen7 Microserver

My 3.5 year old HP Proliant Gen7 MicroServer’s power supply fan starting getting noisy, so I set out to find a replacement. I had a similar issue with the GPU fan on my Sapphire Radeon HD 5770 about a year ago, and I remember from that project, finding a specialty replacement fan isn’t easy.

I scoured forums for hours trying to find a drop-in replacement, but wasn’t very successful. Most people seem to prefer swapping out the stock PSU for a PicoPSU. That moves the transformer outside of the case (like a laptop power supply) but leaves an ugly hole in the back of the system with wires sticking out. I prefer keeping to stock designs when I can, so I wanted to narrow down at least a replacement fan that would fit the stock PSU.

The HP ProLiant MicroServer owners’ thread on was one of the best resources. Specifically, post 896 from bluefull gave several possible drop-in replacements for the stock T&T 4020HH12S-ND1 fan. Additionally, there was some great information in the HP ProLiant MicroServer N40L Owner’s Thread *Part 5* on Shawry, beginning in post #558, describes the main issue with these fans – even though they are rated for 12V, the PSU is actually only putting out 5V. One fan in particular caught my eye, the Noiseblock BlackSilent Pro series. According to the specifications on the site, the fan had a starting voltage of 5V and an operating voltage of 5-13.2V which I had hoped would work as a drop-in replacement. I was able to find the NB BlackSilent Pro PM-2 40mm in the US at and ordered one.

The fan uses a standard 3-pin Molex connector with a signaling cable, but the stock fan uses a smaller 2-pin 4mm mini-Molex connector. Unfortunately, I forgot to order a 2-pin to 3-pin adapter, so I had to resort to cutting the old connector from the stock fan and splicing it onto the new fan’s power cable. I wasn’t overly concerned with doing this as the NB BlackSilent Pro is ingeniously designed with a break-away power connector for using different length power cables and the fan comes with both a 20cm and 50cm cable. At any rate, the fan fits perfectly into the psu, but I wasn’t able to get it to spin up by connecting it to the fan header inside the PSU. Not to worry, the design of the fan and the PSU lends itself to allowing you to connect the fan to a standard 4-pin Molex power connector while still ensuring proper fit into the case.

I installed the fan so the power connector would route outside of the power supply like so:

The HP Proliant MicroServer psu with the replacement NoiseBlocker BlackSilent Pro PM-2 fan

The Proliant MicroServer PSU with the replacement NoiseBlocker BlackSilent Pro fan

I was able to easily slide the power supply back into place, and the connector was then accessible between the PSU and case fan:

The CPU power cable next to the MicroServer case fan

The CPU power cable next to the MicroServer case fan

I then used a standard 4-pin to 3-pin adapter to piggy back off the optical drive power connector:

The PSU power cable connected to a 3-pin to 4-pin Molex adapter.

The PSU power cable connected to a 3-pin to 4-pin Molex adapter

Everything fits nicely in the space behind the optical drive:

HP Proliant Microserver


Fan spun up without issue once the server was powered on.

A side note, I had originally thought the noise was coming from the case fan and went through the effort of ordering a Cougar Vortex CF-V12HPB PWM fan as a replacement, only to find out the HP MicroServer fan header uses a custom pinout. The server will not boot if it does not properly detect the case fan, so if replacing the case fan, you’ll need to swap the conductor pins to the proper slots.

28 thoughts on “Replace noisy power supply fan in HP Proliant Gen7 Microserver

  1. Hi Jeff, I am about to buy HP n54l.

    I want to replace the original noisy supply fan just like you did.

    However, I have couple questions:
    1. Is there a warranty sticker on the power supply that you need to void to disconnect the original fan?
    2. Is the original fan connected to the PCB inside the power supply or to the motherboard outside of the power supply case?
    3. I see that you have connected the fan to the molex externally – do you regulate the fan somehow or you just leave it to run at 12v? Or do you regulate it manually/automatically?

    Thank you for your answer.

    Have a nice day.

    P.S.: if you have more photos of the power supply itself, I would be grateful if you can publish them.

    • 1. There was no warranty sticker.
      2. The original fan is connected to the PCB inside the power supply.
      3. No need to regulate the fan since the NoiseBlocker is dead silent.

      Btw, the original fan wasn’t loud until after about 1.5yrs of use. Also, I double-checked to see if I had any more pics of the power supply and unfortunately, I don’t.

  2. I also has a noise Power supply fan. I ended up replacing it with a Sunon 40x40x20mm HA40201V4-999 MagLev Super-Silence fan. I picked this fan because it starting voltage was about 4.7 volts. I ended up soldering on the old fan lead to this fan, keeping all the wiring internal. I cannot believe how quiet this made the Microserver. Do a search on ebay they are around $10-$20 bucks.

    Cheers Jase

    • Hello,
      I’ve just bought this Sunon and made some tests.
      I’m not very confident in plugging it directly to original 5v PCB out power supply, thinking there won’t be enough air pulsed but If you plug it 12v out Motherboard, it is clearly too loud and neither regulated….
      Don’t you have problems ? Thx.

    • Thanks for the recommendation. I bought this Sunon, and it is remarkable the difference it made. Thanks again!

    • Another vote for the Sunon HA40201V4-0000-999 Brushless 12V DC Axial Fan, 40 x 40 x 20mm … It is completely silent and seems to shift enough air, even when supplied with 5V.

      Minor issues:
      * Soldering and assembly required. I had some spare 2mm Single End 2P Male JST-XH cables I bought on ebay. I can’t remember whether had to swap the red and black wires, just use common sense and compare with the original.
      * Cable management: The original fan had a notch to keep the supply cable flush. With the Sunon fan, the cable goes over the plastic case but doesn’t seem to be squished or pinched anywhere inside the N54L enclosure.
      * The screw holes in the fan case are larger than in the original fan, so you won’t be able to reuse the two screws the original fan was secure with. You will need thick “fan screws”, but they do fit through the original enclosure holes, no worries there.

      All in all, really happy with the swap. Cheers!

  3. I got the NB-BlackSilentFan XM1 fan to replace the noisy PSU fan in my N36L However it wouldn’t spin up. I knew it was getting power as I could see it twitch when I started the server and the optical drive powered up OK which was piggy backed off it.
    I ended up taking the rubber grommet out of the stock PSU fan and topping up the fan’s reservoir with 3 in 1 oil. The fan is behaving itself for now, but if it fails again I will try the PM-2 mentioned in this article.

  4. I have a MicroServer N36L. Same issue. The PSU fan became extremely noisy after I shut down the server and restarted it. Here’s what I ordered from Amazon. This was very easy once I knew the type of fan to look for. I knew I needed a replacement for the T&T 4020HH12S. This fan from Amazon was a great fit and is super quiet. It has 2 leads just like the original so all I had to do was splice the wires together (new fan to old wires in PSU) and I was back in business. This is a great price also (especially if you are an Amazon Prime member).

  5. Hi,
    Does Noiseblocker NB-BlackSilentPro PM-2 or HA40201V4-999 provide enough cooling for the PSU components?
    The specs says:
    Airflow: 5.5 CFM for HA40201V4-999 and 5.4 CFM for the NB-BlackSilentPro PM-2

    Original fan:
    Airflow: 8.36 CFM

  6. Back again because the 3 in 1 oil in the stock fan was indeed only a temporary cure. The fan had suddenly become extremely loud again. I followed the directions given on Jeff’s blog and successfully got the replacement fan to spin up using the P6 optical drive power connector.
    My only issue was actually telling if the fan was spinning or not. The PM-2 fan is extremely quiet and I couldn’t see through the back mesh of the server’s case if it was spinning or not. I ended up taking the power supply out again and then powering it up outside the case. I could then see that it was spinning. I wish I had done that to begin with!

  7. Pingback: Anonymous

  8. Hi Jeff,

    I also own a N54L and I would like to make it more quiet.
    Could you please tel me weather is possible to add an adapter between the Noiseblock fan and the standard connector to avoid having to connect to the standard 4pin molex and keep everything as close to stock as possible.

    Thank you !

    • The problem with the Noiseblocker fan and stock connection is the voltage. It needs more than the PSU fan header supplies, so using a 4pin molex is the only option with that fan. You might try one of the other fans others have recommended.

      • Hi Jeff,

        In any case, which 2 to 3 pin adapter should be used for one of the suggested fans? There seem to be several types of 2 to 3 pin adapters (types “A” to “D”, apparently?) and I don’t know which one this is.

  9. I just ordered a 5v Noctua NF-A4X10.
    Have anyone tried fitting a 5v silent fan as a replacement?
    Should be fine power-wise, but whether or not it will provide enough cooling is unclear.
    I’m hoping the 4,8cfm of the Noctua will be sufficient.

    • Just finished installing the Noctua fan in my N54L.
      It was almost a direct swap. I had to cut the original connector off the old fan and splice it on to the new one. That was expected.
      Also the Noctua is only 10mm deep vs the 25mm original, but a round of electrical tape sealed off the hole behind the fan to keep the airflow going through the PSU.

      After reassembling the MicroServer i powered it up and the fan started immediately.
      Server booted without a hitch and is now running with an almost dead silent PSU.

      It is a bit pricey, but i can fully recommend the for this mod.

      • Hi Nico, I’m struggling to understand how the 5V Noctua running at full speed (4,500 RPM) is quieter than the stock fan (7,000 RPM @ 12V) running at 5/12 of it’s rated voltage (roughly 2,900 RPM). The Noctua is rated at 17.9 dBA, so that is what you are presumably getting, whereas running the stock fan (31.9 dBA @ 12V) at 5V should yield something like 13.29 dBA. Everything made sense until I realised that the stock fan is actually a 12V fan! Did you definitely buy the 5V Noctua and not the 12V version?

        • I definately bought the 5v and it is noticeably quieter than the original.
          But to be fair the old one had some years on it so it might very well have been noisier than when it was new.

          • To be completely fair you can’t calculate the noise level of a fan based on it’s input voltage like that. Unless you had a stock fan, ran it at 5V and measured its noise level, there’s no way to know how loud it runs at a non-standard voltage.

  10. Pingback: HP Proliant G7 N54L Freenas 9.3 NAS Build Log « Morning Lab

  11. Hi
    thanks for the suggestion for a replacement fan and the instructions. Working perfectly (& silent) now.
    I’m still amazed of HP’s decision to use that low quality fan in a “server class” product.

  12. Hi,

    I’m trying to make a Noiseblocker “NB-BlackSilent Pro 40mm (3800 RPM)” to work in my N54L. But i have a similar problem as ANDREW, the fan twitch when I start the server but it doesn’t seems that he want to spin correctly.
    The fan is connected to a 4pin molex with something similar to this.

    I even tried to connect it to P6 optical drive power connector without luck.

    Any idea of what could be the reason ?

  13. Hi. I find this fan Scythe Mini Kaze Ultra and I think is a good replacement for the power supply fan, and NB fan, beacuse this one is a 2 pin fan and is not neccessary an adapter (3 to 2 pin). only 1 db more than NB (NB 18db 3800rpm and this one is 19,5 and 3500 rpm).

Leave a Reply

Your email address will not be published. Required fields are marked *