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.

HP Proliant MicroServer

I have been wanting to upgrade my home server for quite some time and have been eyeballing WHS machines as I was looking for something with a small footprint. While I would normally build my own system, cases for mini-ITX boards that have space for at least 4 HDD’s are quite expensive. In fact, the only one I could find that really fit the bill was the Chenbro case. I also had my eye on the ACER H340 series (now H341 and H342), but when I found the HP Proliant MicroServer, it was exactly what I was looking for.

A quick peek at the specs:

  • AMD Athlon II Neo N36L Dual-Core processor @ 1.3GHz w/ 2M L2 cache
  • 2 DIMM slots supporting up to 8GB DDR3 PC3-10600E unbuffered ECC RAM @ 800MHz (while ECC is supported, it is not required)
  • AMD RS785E/SB820M Chipset
  • Integrated SATA controller with RAID0,1 (this is done in the driver)
  • 4-port SATA backplane supports up to 4x2TB LFF SATA drives (ships with single 160GB HDD)
  • Single ODD SATA port (forced IDE mode)
  • Embedded Broadcom NC107i PCI Express Gigabit Ethernet Server Adapter supports PXE & WOL
  • Onboard VGA with 128MB shared video RAM
  • 1x PCI-e Gen2 16x half-height full length slot (max 25W)
  • 1x PCI-e Gen2 1x half-height full length slot
  • 7 USB ports (4 on the front, 2 in the back, 1 internal)
  • 1 rear eSATA port
  • 200W 1U Flex ATX Power Supply
  • Trusted Platform Module support
  • IPMI 2.0 compliant
  • Optional ILO management card

I made a few small modifications to the base configuration by adding 2x4GB PC3-10666 DDR3 RAM modules (this was non-ECC consumer grade RAM), a CD/DVD-ROM drive, 2x1TB Western Digital Caviar Green HDD’s, and a 16GB Patriot memory stick (to run ESXi). The integrated CPU supports AMD-V and XD bit required for virtualization, so running ESXi (and I suspect Hyper-V) works fine. The system itself is light-weight and the perfect size (10.5″ x 8.3″ x 10.2″). With the exception of the HDD caddies, the case is very sturdy – metal all around.

Great compact design in my opinion. Cables are routed well and the motherboard is mounted to a tray secured by two thumb screws. You need to disconnect cables and remove the motherboard in order to install PCI-e cards and RAM.

You’ll notice what looks like a PCI-e x4 slot on the motherboard. That’s actually for the optional remote management card and adding it will cover the PCI-e x1 slot. The motherboard sits underneath the HDD housing, so RAM with certain size heat-spreaders may not fit. The internal USB connection is in the lower left-hand corner of the motherboard. You’ll notice there is plenty of room for a large USB flash drive if you so choose.

The HDD drive caddies are plastic and the backplane has necessary SATA connections. Screws are located on the bottom inside the front door. There’s also a handy torx driver for working on the system.

Plenty of clearance for the USB flash drive that will hold the ESXi installation.

As far as the ESXi installation goes, couldn’t be simpler. I attempted to use SYSLINUX to install ESXi from a USB flash drive, but couldn’t get the installation going so I hit Best Buy for a cheap SATA CD/DVD-ROM drive. Note that the system has just a standard Molex power connector for the ODD, so you’ll need to purchase a  Molex to SATA power cable. Total installation time was only about 10 minutes. I am using the supplied 160GB for VMDK storage and will use RDM for the 1TB HDD’s to create a software R1 array since the embedded RAID controller is not supported by ESXi.

While 8GB of RAM won’t be enough to virtualize a datacenter, there should be plenty of RAM to run a few Virtual Machines. I was able to P2V my domain controller (was an Optiplex GX1 PII 400MHz box with 256MB – I know … well past it’s prime) in about an hour (only had 100Mbps nic) and am currently downloading Windows Home Server codename Vail to test out WHS in a virtual machine. All-in-all, if you’re looking for a home server or virtual test lab, this box is a great fit!