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HP Recommended
Z620
Microsoft Windows 10 (64-bit)

Hi whole forum 🙂 !

 

Im modding my Z620 and i decided to change all my stock fans with noctuas, their silence being main reason and also i got them really cheap 😄 But i run onto problems with system detecting its low speed ( low fan speed ) and i simply cant find an solution to this. Also when booting i got fan error messages.

I changed front intake fan, no problems only during boot. 
But i wanted to change a stock fan on my z420 liquid cooling kit for noctua, because the stock one is only good at it slowest speed, otherwise its very high pitched noise its driving me nuts. And this is where i run into problems, that noctua fan will just pitch itself into 100% and system cannot identify it. Im out of ideas ... SO my question is, if there is any way how to use silent fans without problems ? 

 

Thanks for any help !

David

10 REPLIES 10
HP Recommended

The HP workstation motherboard system of maintaining balanced cooling (and a safe level of cooling) is complex and tightly engineered.  Pulling out all the HP fans and putting in others is generally a bad idea.  For example:

 

The HP heatsink/fan combo for certain higher wattage processors requires a special fan that has 5 rather than 4 connections to the motherboard header.... there are the 4 standard PWM fan wires from/to the fan, plus a ground jumper from pin 1 to 5 added to the fan's plug end.  That is how the motherboard knows a proper "Performance" HP fan is present.  If it sees a high wattage processor without a "Performance" fan at the heatsink it will complain or halt boot.

 

Another example:  The nice Noctua PWM fans have the standard 4 fan wires and are built to run slow and quiet with no PWM braking applied.  The HP fans are specifically selected to run quite fast if no PWM braking is applied to them.  This is two ends of the spectrum.  So, when the standard HP PWM braking is auto-applied to a Noctua PWM fan it changes from running slow and quiet to running way too slow.  Then the HP motherboard detects impending disaster and ramps everything up.... crisis mode.

 

Your best solution is to first make sure that the fans in BIOS are set to run as slowly as BIOS will let them.  Hopefully you know about that baseline setting.... it is in BIOS for every HP workstation.  Second, you need to learn about the high quality Noctua resistor-based 3-wire or 4-wire fan speed reducers.  Go back to your HP fans that came with the Z620, get some of those Noctua adapters (look it up.... they come with different Ohm resistor values, easy to find via Google).  Then harvest just that part of the adapter and insert that wire/resistor in-line on the 12V power line of the HP fans.  Throw the rest away.  I'd start with the lower resistor value "Low Noise Adapter" (LNA) rather than the ULNA. 

 

The 4-wire HP fans all use the same normal sequence of PWM wires..... ground, +12VDC, rotor speed feedback to motherboard, and PWM braking signals from motherboard out to the rotor via pins 1-4, respectively.  The motherboard headers all have a tiny triangle at the pin 1 end, printed on the motherboard surface and the order they are in is the standard across all PWM headers.  No secrets there.

 

In this way you will be able to fine tune your HP fans to something you like but not whack the whole system so far out of balance that the motherboard goes into thermal crisis prevention mode.

HP Recommended

sound advice from "SDH" and this is also why changing the HP case to something else is not advised as HP designed the case,  motherboard and fan placement  as a set and that the HP cooling shrouds (if used) are installed

 

when you use a diffrent case and/or fans it's really hard to get to the same cooling capacity as the stock hp workstations using 3rd party solutions

HP Recommended

Hi Daaavooo,

I would probably advise against replacing the fans, if you are not comfortable with a bit of wire soldering. I have replaced all the fans (except the CPU fan) for now with Noctua fans.

  • Noctua NF-A9 PWM
  • Noctua NF-A6x25 PWM
  • Noctua NF-A4x20 PWM
  • Noctua NF-A12x15 PWM (not recognized)

It just turned out to be more work than expected and I'm not sure if the

reduced noise is worth it.

All Noctua fans work fine, except the chassis fan where i chose the Noctua NF-A12x15 PWM. That fan is spinning but not recognized during boot time. Therefore I get a fan warning and have to press F1 to start anyways.

I still had a few problems. The plastic housings for the fans all have some notches. These notches block the Noctua fans from spinning. You will need to cut them off with a wire cutter for example.

All the plastic housings for the molex connectors are HP specific. You can just use the cables in the Noctua kits (especially the extension ones, if you plan on using the fans in stock config in other devices later). Just use a needle or small screwdriver. press down at the metal in the housing and pull back the wires.

Then you can insert the Noctua cables into the HP connectors. For the Memory and the chassis fans at the back you will have to do some soldering.

The standard HP fan protectors at the two back chassis fans do not fit will with the Noctua fans. Just glue them onto the fans or buy metal ones.

 

I found the pinout of the fans printed onto most of the PCBs of the fans (+/-(gnd) and cs).

 

If you are still into the project just give it a try. If you need the pinout i can look it up.

HP Recommended

Hi ! 

 

how did you manage to pass the fan problem during startup ? or are you just pressing F1 each time you boot ? Because i ended not changing anything for that matter, cuz its not elegant for me to press F1 each time...

I dont have slightest problem with soldering, if it would actually change anything :D. You even soldered two back exhaust fans togehter to that HP 6pin ? 

Thanks for reply 🙂 

HP Recommended

Hi,

yes at the moment this is what I'm doing. But it is just the front 120mm fan which is causing the error. Maybe I got confused and mixed the tacho and the control cable for the fan. It is running all the time. I will switch those tomorrow and tell you if it is recognized afterwards.

I could switch this back to the original and there would be no error. The other fans are recognized just fine (two memory fans and the two at the back of the case).

Yes I soldered the Memory and the two rear fans. They work just fine.

 

You will have to solder the memory fans, too as those have although a 6 pin connector. I used the extension cables which came with the Noctua fans, because I didn't want to break the original fan cables. This way I still have a standard Fan, if I want to use those in another machine later.

I just pulled the molex connectors out of the Noctua housing from the extension cables by slightly bending the small metal nose on the one side of the connector. Afterwards i bend it back a bit and put it into the HP fan connectors. Then i soldered the ground and voltage cables together.

 

This way I just had to solder 4 cables for ground and voltage. It looks a bit more messy, but it works fine.

Just make sure you break away the notches of the fan housings. If you try to move the fans after installing them you will recognize that they get stuck, if the notches are not removed. You won't be able to see the broken off notches, as they are on the inside of the fan housings.

 

EDIT: I might add some photos, too.

 

HP Recommended

Hi Do you have any photos 🙂

HP Recommended

Hi,

sorry for the late reply. I had a lot of work to do the other days. Here are the pictures. Especially the memory fans could be connected better, if would not use the extension cables and just solder the fan cables properly.

The front fan is recognized after changing the pinout. Basically the pinout is just like a standard PWM with special HP connector. The colors for the cables is here: https://www.overclock.net/forum/61-water-cooling/1595707-ek-ddc-pump-pinout.html

The Rear fanout is:

1. PWM Fan1

2. Tach Fan1

3. WPM Fan2

4. Tach Fan2

5. + Fan1/2

6. Gnd Fan1/2

 

Chassis rear fansChassis rear fans

 

The chassis front fan is basically a standard PWM pinout with a special HP housing.Chassis front fanChassis front fan

I routed the extension cables out here, as there was to little space on the back and didn't want to cut the fan cables. This makes removing the housing of the fans a bit more difficult (the cables have to run right/left of the locking mechanism).

IMemory fans cable routing frontMemory fans cable routing front

 

Cable routing at the rear side of the memory fan housing.Memory fans cable routing rearMemory fans cable routing rear

 

The soldered memory fan cables.Memory cable solderingMemory cable soldering

All fans are recognized now. If a fan is not recognized make especially sure, that the fan is not blocked by anything. Just remember that HP has some notches in the housings hindering none HP fans from spinning by blocking the rotor.

HP Recommended

Wow amazing 😄 it looks that at least something aftermarket-y will work in this HP 😄 

So now you dont have any F1 button pressing issue ? even with those small memory fans ? NEAT ! 

What about acoustics, is it better ? maybe not whole lot quieter but at least if the noise is better, if you know what i mean.

Thanks for everything ! 

HP Recommended

Hi Daaavooo,

yes no more pressing F1 at boot. And all fans work and spin. Concerning the noise I'm not sure about the reduction. I can still definitely hear the fans spin. But this might although be a problem of Debian not recognizing the PWM controllers. I can't control the Fans from the OS therefore the BIOS is setting the speed. With drivers from HP this might be less of an issue.

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