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Archived This topic has been archived. Information and links in this thread may no longer be available or relevant. If you have a question create a new topic by clicking here and select the appropriate board.
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Attached is my best info on tweaking the xw6400 and xw6600 workstations to run more quietly with no increase in internal temperatures when measured with the specific utilities noted (and also from BIOS in the xw6600).

 

I mention the Noctua 4-wire resistor fan speed reducers, and those work great for the memory and chipset fans.  I also have swapped parts from the xw6600 into the xw6400 (fans, and fan shrouds) to gain the benefit from the more recent HP engineering.

 

Overall my optimized builds of these workstations run as quiet or more quietly than the Z620, for little cost.  The PWM-preserving 4-wire speed reducers you want to search for are most easily bought via a 3-pack from Noctua, found if you google NA-SRC7.  Use one on your memory fan, and one on your chipset fan and memory fan if you have a xw6600.  The other methods noted are more of a project, but I'd recommend doing at least the adapter addition(s).

 

See attached:

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A little added information on the xw6600's small chipset fan that runs very fast in the xw6600 and is worth slowing down.  The Northbridge chipset on the xw6400 has only a heatsink..... no fan at all other than air movement drawn over that heatsink by the memory fan.  I have seen no cooling deficit by dropping this chipset fan speed from 3745 down to 2752.  That roughly 1k RPM speed reduction does significantly reduce the total noise from the workstation, however.  The same concept goes for why I add a Noctua 4-wire LNA fan speed reducer to the xw6600's memory fan.... lower fan speed/noise with no measurable increase in memory temps, while still maintaining the motherboard's ability to ramp up fan speed automatically if needed.

 

HP uses the 40x40x20mm PWM controlled Delta EFB0412HD which has a -7R49 modifier (on the label).  Those modifiers identify fine details of the fan, and for this one it indicates that PWM control has been added, the wires are short, and the white plug end is the conventional PWM type.

 

If you were to ever get only a 3-wire replacement fan it will run at full 12VDC speed, with no HP PWM throttle applied.  Here's the RPMs:

 

3-wire (PWM wire disconnected, or 3-wire fan):                      7500 - 8500 (measured on several xw6600s)

No adapter and with baseline HP PWM throttle applied:      3745                (averaged)

Noctua LNA 4-wire adapter plus baseline HP throttle:          3101                        "

Noctua ULNA 4-wire adapter plus baseline HP throttle:       2752                        "         

 

The 4-wire Noctua ULNA adapters are hard to obtain, but at least add in the NA-RC7 ULNA 4-wire Noctua adapters on your xw6600's memory fan and its chipset fan.  Those are easy to find as a 3-pack by searching for "NA-SRC7". 

 

Attached are the Delta specs with the 12VDC HD version of that fan highlighted, and a pic of the fan with that modifier code on its label.

 

 

 

 

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HP Recommended

A little added information on the xw6600's small chipset fan that runs very fast in the xw6600 and is worth slowing down.  The Northbridge chipset on the xw6400 has only a heatsink..... no fan at all other than air movement drawn over that heatsink by the memory fan.  I have seen no cooling deficit by dropping this chipset fan speed from 3745 down to 2752.  That roughly 1k RPM speed reduction does significantly reduce the total noise from the workstation, however.  The same concept goes for why I add a Noctua 4-wire LNA fan speed reducer to the xw6600's memory fan.... lower fan speed/noise with no measurable increase in memory temps, while still maintaining the motherboard's ability to ramp up fan speed automatically if needed.

 

HP uses the 40x40x20mm PWM controlled Delta EFB0412HD which has a -7R49 modifier (on the label).  Those modifiers identify fine details of the fan, and for this one it indicates that PWM control has been added, the wires are short, and the white plug end is the conventional PWM type.

 

If you were to ever get only a 3-wire replacement fan it will run at full 12VDC speed, with no HP PWM throttle applied.  Here's the RPMs:

 

3-wire (PWM wire disconnected, or 3-wire fan):                      7500 - 8500 (measured on several xw6600s)

No adapter and with baseline HP PWM throttle applied:      3745                (averaged)

Noctua LNA 4-wire adapter plus baseline HP throttle:          3101                        "

Noctua ULNA 4-wire adapter plus baseline HP throttle:       2752                        "         

 

The 4-wire Noctua ULNA adapters are hard to obtain, but at least add in the NA-RC7 ULNA 4-wire Noctua adapters on your xw6600's memory fan and its chipset fan.  Those are easy to find as a 3-pack by searching for "NA-SRC7". 

 

Attached are the Delta specs with the 12VDC HD version of that fan highlighted, and a pic of the fan with that modifier code on its label.

 

 

 

 

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Scott, thank you for your tips and information on HP workstations.

With regards to fan noise : Have you ever stripped a power on/off, led, speaker cable from the xw6600 and pulled out the transistor/thermal sensor? In another thread about the xw4400/4600 a mmbt3904 was mentioned, but I would like to know if the same transistor is used in the xw6600.
I suppose mine is broken and due to shipping costs (I live in the Netherlands), the cable assembly you referred to (from ebay) is still rather expensive. To replace an otherwise functional cable just because of a broken 50 cent part seems a bit overdone.
If I know which type of transistor is used, I would cut off some of the heatshrink and solder a new transistor or thermal sensor to the wires. As far as I know several transistors and sensors could be used: sot-23 (mmbt3904), to-92 (2n3904) and probably some other sensors like the LM35DZ and PTY-81, 82.

Any information is very much appreciated.

Kind regards,

Roland
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nmbt3904 = 2n3904

 

this is a common and cheap transistor.

Any other NPN type transistor will also do the job.

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Gabornico, thank you for your reply.

I know mmbt3904 and 2n2904 are identical as far as their (average)specs and application are concerned. However, mmbt3904 is meant for surface mounting, whereas 2n3904 is mostly used 'free air'. I suspect the npn resistor used in the xw6600 is indeed 2n3904. In different forums on electronics it is suggested the mmbt3904 to be more reliable in the long term and more resistant to environmental conditions ( moist, shocks, sudden changes in temperature etc. ).
I attached a picture showing the application for 2n3904 and mmbt3904 and an image of a mmbt3904
soldered to a twisted pair cable. By soldering the mmbt3904 at an 45 degrees angle, the collector and base will be connected (diode-connected).
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I have personally used a xw8600 front cable set (which includes the ambient air thermisitor you are interested in) in both a xw6600 and a xw6400 that had the their original thermisitors go bad.  That cable was longer, but worked just fine.

 

This indicates that the thermisitor in those different cables is the same, and likely also those in the xw4600.  You can strip open that cable and extract the thermisitor and its two wires if you wish.

 

Beyond that is beyond me, but if you figure things out at a deeper level please let us all know.

 

 

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Ro808, the front cable uses a 2N3904 in the common 3 lead package, not a surface mount MMBT3904.  HP does not use the surface mount transistor in the cables, because the 3 lead package is easier to connect to wires and there is no electrical reason to use the SMT part (in this application, at least).

 

Sorry for the confusion.  The diagram I posted a while ago should have listed a 2N3904 instead of an MMBT3904. 

 

Previous Workstations going back several generations all used a 2N3904 in the front cable as temperature sensor, as Scott D. Harrison discovered.  Cables sometimes came in different lengths so they routed better in the chassis. 

 

 

P.S.  Off topic - do you drive a Mazda RO 808 rotary car?!?

I am an HP Employee.
My opinions are my own, and do not express those of HP.

Please click "Accept as Solution" if you problem was solved. This helps other forum readers.
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Dan, thank you for the information.
Before I read your reply, I decided to order some 2n3904 transistors, because the shape of the original transistor (still covered by the heatshrink) seems identical. Besides, the 2n3904 is easier to solder to a wire as stated in your reply.
I will post some images of the 'process'. This may be helpful to other xw owners who wish to replace the transistor themselves.

Regarding your other question: I do not drive a Mazda Rotary car. However, I did recently sell a vintage Nikko RC 1:18 version of the Mazda RX-7 :-). Fascinating technology, which initially became widely available in the late sixties with the introduction of the rather futuristic NSU Ro-80. Unfortunately the car's reliability suffered from oil leakage issues due to a badly designed sealing of the rotary combustion chamber. Until recently, Mazda sold rotary powered sport cars and Suzuki produced a motorbike with rotary engine in the seventies.
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Scott, have you ever checked PWM operation of fans fitted with Noctua NA-SRC7 4-wire resistor fan speed reducers?
I stumbled upon a post from someone who stated the PWM wires are bypassed in these reducers. He actually removed the mantle from one NA-SRC7 and judging from the image, Noctua did not change the wire order or bypass any wires. The attached images show the stripped NA-SRC7 and a low noise adapter cable from another supplier.
I tend to doubt this statement as Noctua is well known for its top quality products.
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I very much like the Noctua speed reducers.  You are correct that Noctua does not touch the PWM wire at all.  Here is more info on those adapters:

 

http://www.overclock.net/t/1382222/noctua-lna-resistor-ratings

 

I contacted Noctua in Austria a couple of years ago and had them send me over a package of a bunch of the 4 main 4-wire (PWM) resistor speed reducers they provide, and I ended up only really using the ULNA and LNA ones.  The early 3-wire nonPWM Noctua fans usually came with two different speed reducers... the slower ULNA (Ultra Low Noise Adapter) and a faster LNA.  With the advent of the PWM Noctua fans those came with the 4-wire equivalents of the 50 Ohm NA-RC7 (LNA equivalent) and the 81 Ohm NA-RC6 (ULNA equivalent).  There are a few other variations depending on the fan you buy, but those are the two you want to know about.

 

These are high quality product, and in my best xw6600 builds I put in 3 total.  For the little HP Northbridge PWM fan I add in a NA-RC6 to drop its much faster than necessary speed down to a reasonable level.  For the 92mm HP memory fan I add in a NA-RC7 to drop its unnecessarily fast speed down, but to a lesser degree.  For the front "PCI" fan that I ghetto mod in (one of several types of HP PWM 92mm fans I get used from eBay) I use whichever is needed to get the net RPM down to about 1000 up front.

 

There is a black-sleeved version of the unsleeved pair you show that is on Amazon, and is reliably the equivalent of a NA-RC7 from my testing.  However, the non-sleeved version does not give the result you'd expect so I really question its quality.  Another problem with that company is they use cheap fan plug plastic parts that do not guide the female metal end that gets slipped into the plastic holes, and those can then rotate/shift around and you may not get a reliable connection on the female plug end.  The plug ends I have posted about from Mouser.com are A+ quality, and have the tiny internal guide grooves that work properly, as do the ones from Noctua (as you'd expect).

 

HP and Noctua use standard PWM wire order, from pin 1-4:  Ground, 12VDC, RPM sense from motor back to motherboard, and PMW control from motherboard out to motor.  In your pic from the deconstructed Noctua NA-RC6 that would be Black, Yellow (with the resistor), Green, and Blue.  The resistor just drops the VDC to the motor, and the other three wires including RPM sense/PWM control are left untouched.  The HP motherboards do not watch for a particular RPM and compensate for the reduction in the VDC by the resistor by boosting PWM feedback to the motor to speed up.  That is why this fine tuning can work so well.

 

Noctua recently came out with a 3-pack of the NA-RC7 for not cheap (about $7.00 USD on Amazon.... the NA-SRC7), but it is a reasonable price considering the quality, and that they'll last forever.  I've even harvested the resistor wire from some of my old 3-wire Noctua ULNA leftovers and transplanted it into spare 4-wire LNA sets I had extras of.... I'm running out of my Austrian NA-RC6 ones, which I wish Noctua would also make available in a 3-pack.

 

Long winded answer, but knowing this trick makes my best xw6600 builds quieter than my stock Z620 builds, with zero problem with overheating.  HP has increasingly realized how valuable quiet is and started fine tuning the acoustics more thoroughly in the Z600/800, and expecially in the Z620/820 and beyond.

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