Talpadk’s Blog

March 10, 2012

HP Proliant N40L Filter

Filed under: Uncategorized — talpadk @ 1:32 pm

I recently bought a HP Proliant N40L “server” as an upgrade to my QNAP 409.

And as with my QNAP I would like a filter that prevents most of the dust in my living room from entering the Proliant.
Before I build a filter out of a piece of cardboard and some paper towel for the QNAP I have once had to vacuum it due to a slight build-up of dust.
After the filter the inside remained a lot cleaner and I only had to clean/replace the filter, a lot safer and easier than cleaning the whole thing.

If some paper towel works for a QNAP then why not a Proliant?
Anyway here is a tiny How to “build” a simple and cheap filter for a Proliant N40L

First you need to remove the plastic that covers the door.

In order to do that you need to remove the lock this involves: Removing the screw holding the metal “bar”, then removing the nut that holds the locking mechanism in place.

You can now remove the plastic covering the metal door by carefully releasing the thee plastic hooks at the top of the door.

Next you need to cut a 19×14.5 cm piece of paper towel.

I removed half the layers of paper to keep the pressure drop across the filter low.
Last time around I used paper towel with only two layers which was much easier to separate than the 4 layer stuff I used this time…

Now you need to tape the paper towel onto the outside of the metal door.
If the Proliant is running and the door is closed the paper will be held in place by suction, making it a very easy job indeed.

Cut a hole in the paper towel for the locking mechanism.

Put the plastic covering back on, hiding the filter.

Reinstall the locking mechanism.

Close the door and admire your handy work while drinking your favourite beverage.
(Beer can be used during this step)


  1. Does this not massively reduce the airflow through the chassis?

    Comment by baldmosher — March 23, 2012 @ 9:31 am | Reply

    • Indeed as with any type of filter it does significantly reduce the airflow through the chassis.
      The pressure drop across the filter is actually large enough to reverse the airflow through the chassis fan over some areas of the fan surface.

      That said I took the following measurements after installing the “filter”:

      Door Open:
      temp1: +30.5°C (high = +70.0°C, crit = +100.0°C)
      /dev/sda: WDC WD1000FYPS-01ZKB0: 32°C
      /dev/sdb: WDC WD1000FYPS-01ZKB0: 32°C

      Door Closed (with 2/4 layers):
      temp1: +41.5°C (high = +70.0°C, crit = +100.0°C)
      /dev/sda: WDC WD1000FYPS-01ZKB0: 37°C
      /dev/sdb: WDC WD1000FYPS-01ZKB0: 35°C

      (Using “sensors” and “hddtemp”)

      Those temperatures are not a cause for concern for me.
      However I still have a remaining ToDo item, measuring the PSU exhaust temperatures…

      I’m also considering replacing the PSU unit with a “PicoPSU-80” and a DC power supply.
      Which would remove some of my concern about the PSU overheating, as the PicoPSU-80 has a 86% to 96% efficiency most likely in the 94-96 range as I shouldn’t be drawing that much power.
      It would also remove the PSU fan, which I find to be the most noisy fan in the system.
      (It would also allow me to build my own 12V DC (regulated) UPS system, but that would mostly just be a fun project, as a better/more efficient way to spend my time would be to just buy a normal 230V AC UPS)

      Comment by talpadk — March 24, 2012 @ 8:40 am | Reply

      • My N40L is in a cupboard so I suppose it’s more sensitive to poor/recirc airflow, but I did the mod using Plenty (fka Bounty) which is a knitted towel, using 1/3 sheets, and CPU temps hover around the 55°C mark, higher when under strain, eventually causing BSOD errors (Win7x64 Ult) on a daily basis when idling, and more frequent under strain (e.g. watching iPlayer). GPU temps appear fairly high but that quickly ramps up when it’s in use (e.g. XBMC). My GPU has a fan so it’s not such an issue, but the Turion appears to cause a BSOD when it goes over 60°C. Opening the door drops the CPU temps back down to the more normal 30°C and GPU down to 40-odd, even with the cupboard door closed, so I’m removing the towel from mine and will live with the extra dust. I find the door and HDD caddy collects most of it anyway.

        I might try again if I can find some packing mesh the right size (the grey stuff you get to protect PCBs on video cards)

        I agree that the PSU fan is very noisy though. I am tempted to install a pico but as it’s in a cupboard that seems like pointless overkill. If it was in the room with me I’d do it.

        Comment by baldmosher — April 14, 2012 @ 10:15 am

      • I stumbled upon this through google, I purchased an n40l as a downstairs media server/center and it sits next to my TV. All the reviews spoke of how the server was silent and maybe that’s true in an airport but certainly not in a quiet room and certainly not when compared to the eMachines er1401 it replaced. Through stopping the fans one at a time it seems the culprit is the psu fan, the big one actually seems relatively silent and care free. I’m wondering if either of you guys came up with any other ideas on how to combat this. I’m currently tempted to open the psu up and replace it with a quieter fan but that may end up a huge waste of time if it ends up being down to the amount of air being forced through or something.

        Comment by anonyx — August 14, 2012 @ 11:06 am

  2. Anonyx a quieter PSU fan will probably have a lower airflow than the original fan
    And Baldmosher have reported problems when the airflow is reduced (by a filter)

    I have no such problems however I don’t have a graphics card installed, and his problems might be caused by the PSU overheating (I’m drawing a lot less power that he is)

    A “PicoPSU-80” type PSU adapter with an external power brick would remove the fan altogether.
    (Get components with a good efficiency to keep the heat production to a minimum, and of course enough wattage)
    And you should probably block the old PSU fan hole to prevent the chassis fan from drawing “false air”.

    Though I haven’t tied this yet I’m just living with the noise…

    Comment by talpadk — August 14, 2012 @ 4:38 pm | Reply

    • Thanks for getting back to us. I’ve looked more into the picoPSU since this morning and it seems like the best option for what i need. Through numerous searches there seems to be reports that it will handle the hard drives fine and give no running problems nor reduce load so ill get one ordered. Looks like as well as being silent they also reduce power draw by a ridiculous amount (there is talk of 12-14w idle) so that’s nice.

      Comment by anonyx — August 14, 2012 @ 6:38 pm | Reply

      • At least they are supposed to be a great benefit in some MiniITX machines where they used standard PSU units that were basically idling even when the machine were under load.
        This results in the PSU operating far from its point of optimal efficiency…

        If it is as bad as the MiniITX case I’m not sure, but I’m looking forward to hear about your experience.

        Comment by talpadk — August 15, 2012 @ 8:35 am

      • I have a 120W picoPSU with 90w power adapter coming this time tomorrow so I’ll update my findings. I’m not really sure of the electronics side of things so I am unsure why a 120w would only warrant a 90w power adapter but that is how the bundle comes so I imagine it is correct. I read numerous reports that the 80w should more than suffice but I’m planning on running 4 WD Green 2TBs and an SSD from this so figured there would be no harm in moving up the power scale a bit. I’ve also purchased the necessary molex 1 to many adapter and a 24pin to 24pin adapter should there not be enough space for the picoPSU under the drives. I don’t think I have missed anything and after tinkering last night the actual dissemble procedure looks relatively easy. I would guess no more than 30mins to get this running on DC, still a bit of a pain in the arse and an expense I wasn’t expecting but it will mean the unit will be silent and can function for its intended purpose as a media streamer and media center in the lounge once again. Thanks for all your help so far.

        Comment by anonyx — August 15, 2012 @ 2:35 pm

      • Yes it does seem a bit odd indeed, but perhaps the picoPSU has no overload protection?
        And they are trying to ensure that you can’t fry it by supplying a smaller AC adapter.

        But even 90W is quite a bit of power as long as you don’t put a very power hungry GFX card in the Proliant.

        (Ít seems that they are limited to 25W unless it is a PEG slot or they have an external power connector according to: http://en.wikipedia.org/wiki/PCI_Express#Power)

        Comment by talpadk — August 15, 2012 @ 2:51 pm

      • I did not consider overload protection, that is certainly a possibility. 90W should be fine as you say, my only concern is the initial powering on and spinning up of the hardware. From a few posts I’ve read, the hard drives will each be drawing 10w when they first fire up, once they are running they operate at their normal low wattage but its just that initial startup that is a minor concern as I’m also feeding a small ATI HD6450 card which will be drawing upto 25w also. Once the system is booted, im looking at around 40-50w from what I have read which is perfect, sadly I don’t no enough about the power requirements of a device being powered up to make an adequate calculation. No fear though, I will just add the drives one at a time and see how we fair but you can maybe see the concern? (25w + (10w x 4) + cpu) Again though, I’m a software developer and never really looked to electronics so its very possible I have the wrong end of the stick. I’ll update further when the parts are delivered.

        Comment by anonyx — August 15, 2012 @ 5:02 pm

      • Unfortunately it would be a less that perfect overload protection, as the individual voltages on the picoPSU could still be overloaded.
        But from the manual at (http://www.mini-box.com/picoPSU-120-power-kit) (only a 60W AC unit):

        Overload protection
        Over load protection will be effected when either of the loads (+5V &
        +3.3V) exceeds > 200% Max Load.

        It seems that the pico has its own overload protection.
        The combination is more likely just a 90W solution…

        Regarding disk power 10W for a new disk seems about right:

        On the bright side, the GPU will not be drawing its maximum power during startup, and the CPU isn’t that power hungry either.
        According to: http://www.techpowerup.com/reviews/Sapphire/HD_6450_Passive/25.html I would expect the GPU to consume around 6W during power on.

        (Then there is also in-rush currents into the capacitors on the MB, GFX card and so on, but I don think they count as they are “slowly” charged as the voltage rises during power on)

        Comment by talpadk — August 15, 2012 @ 5:37 pm

      • PicoPSU arrived yesterday but I was not able to do a huge amount as the molex 1 to 4 connector had not arrived. That came today and I proceeded with the conversion. Took around 20-30minutes, ridiculously straight forward to perform.and the system is now running near silently. I need to extend the power input from the pico as it is like 15cm and won’t reach the back of the case where i want to mount it but apart from that, a fantastic success. I’ll report back once its all tidied up and the wattage reader has arrived to give proper pictures and specs. Thanks for all your help.

        Comment by anonyx — August 17, 2012 @ 12:06 pm

  3. Any progress on the Pico PSU and wattage reader?

    Comment by Hank — November 27, 2012 @ 10:22 pm | Reply

  4. Not yet, not by me anyway…. But i suppose I really should try it out

    Comment by talpadk — May 11, 2013 @ 8:55 am | Reply

  5. Why not just use some stocking ? Same effect, less interference with airflow.

    Comment by Garetz — July 7, 2013 @ 2:02 am | Reply

  6. For one, I don’t have a nylon/silk stocking…
    But other than that I would expect it to work just fine 🙂

    Comment by talpadk — July 12, 2013 @ 4:22 pm | Reply

  7. The large fan on the back blows air into the unit so I fail to see how a door filter will improve things other than a reduced air flow will result in less dust.

    Comment by Steve Jones — June 27, 2014 @ 7:51 am | Reply

    • Well on my unit it sucks air out of the Proliant, perhaps they have changed that in later models.

      Besides that I’m currently running it inside a small wooden cabinet along with an UPS unit.
      In this configuration I have removed the air filter from the Proliant and filters the air I blow into the cabinet instead.

      Comment by talpadk — June 28, 2014 @ 10:50 am | Reply

  8. I used a Bounce sheet after it had been through a cycle in the dryer, it prevents static build-up and smells nice 🙂 Also not bad as a filtering media. They are flammable though but I don’t regularly start fires near my computers.

    Comment by Mike B — September 4, 2014 @ 4:50 pm | Reply

    • Had to look up the sheets as commercial spamming seem to be occurring frequently here on wordpress 🙂
      I also wondered what they were as I never have heard about anyone adding anything to there dryers here in Denmark.
      Seems to be a quite nasty chemical cocktail, google hit:

      I don’t know if we just don’t dry our clothes that hard here in Denmark (high energy costs) or if we have less synthetics in our clothes.

      Anyway take care using these apparently chemical laden filter sheets.

      Comment by talpadk — September 5, 2014 @ 7:23 pm | Reply

  9. My wife is nurse and she found me doing the filter with paper, and then suggest medical gauze, i have put 2 layers of it instead the paper. I haven’t notice any reduction in the air flow, or increase noise (i think its quiet compared with no filter at all), and temperatures remains the same ( i have monitor this with Nagios).

    Comment by Jose Alberto Morales de los Rios — February 7, 2015 @ 2:30 pm | Reply

RSS feed for comments on this post. TrackBack URI

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Google photo

You are commenting using your Google account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s

Create a free website or blog at WordPress.com.

%d bloggers like this: