Author Topic: Fan replacement on the Rigol DP832  (Read 6257 times)

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Offline ElektronikLabor

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Fan replacement on the Rigol DP832
« on: March 23, 2014, 04:07:09 AM »
Hello,
Some weeks ago I received my power supply Rigol DP832 and I was surprised how loud it is. I decided to change the fan against a quieter one; now I would like to exchange experience with you :)

Sorry for the bad sound quality.
After modification I can’t almost hear any noise of the power supply. I don’t follow this forum, so I don’t know if there exists another solution for that problem. That’s just my way of solving it.

In addition to my explanation you can take a look at some photos here.

First I ordered a quiet 80mm fan: Be Quiet Silent Wings 2
When I received the fan I opened the case of the DP832 and I was very amazed to see two fans! One big fan on the back and one smaller one on the right side of the case! I have watched Daves video
where he tears down the power supply but there was only one fan, not two! :scared:
The second smaller fan makes roughly the same noise as the bigger one, so I immediately bought a second quieter one.

I can’t understand why Rigol decided to build in a second fan. I already know about the heat problems of this Supply; I also watched Daves video about this problem. But I don’t understand how the second fan can help! It is blowing directly on the transformer and it is half covered by the case! The two fans are connected in parallel within one connector.

Some specs of the original fans:
1st original fan:
Model No: Sunon MagLev ME80251V1-0000-A99
Size: 80mm
Noise: 33 dBA
Speed: 3200 RPM
Air Flow: 41 CFM

2nd original fan:
Model No: Sunon MagLev ME50151V3-000C-A99
Size: 50mm
Noise: 30 dBA
Speed: 4900 RPM
Air Flow: 13 CFM

Some specs of the new fans:
1st fan:
Model No: be quieq! Silent Wings 2
Size: 80mm
Noise: 14.5 dBA
Speed: 2000 RPM
Air Flow: 26 CFM

2nd fan:
Model No: Sunon MagLev HA50151V4-0000-999
Size: 50mm
Noise: 17 dBA
Speed: 3200 RPM
Air Flow: 7.7 CFM

You can see that the new fans are much quieter but also weaker as the original ones! Overall the new fans are 40% weaker! I worked some time with the modified power supply but I didn’t mention any problems even with bigger loads over a longer period of time.

To verify the new fans I measured the temperature of the heat sink of the linear voltage regulator which became so hot in the past. I think this regulator powers the internal system of the DP832. I measured it before and after the replacement of the fans, during the measurement all outputs were switched off. You can see the measurement setup on the pictures I mentioned vefore. Below you can find the graph of the heat build-up. I turned on the supply in t=10s switched it off in t=500s.
You can see that with the new fans the heat sink gets 8°C warmer after 490s.

I will definitely keep a close eye on the heat of my power supply, but like I mentioned before I couldn’t see any problems until now.  :)
« Last Edit: December 18, 2014, 11:09:30 PM by medvedev »
 

Online HighVoltage

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Re: Fan replacement on the Rigol DP832
« Reply #1 on: March 23, 2014, 09:05:34 AM »
I just bought a LeCroy 354 scope and it is loud, like too loud 52 dB(A) !
But then, it has a huge airflow coming out and I might do not get away with a
lower airflow fan.


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Offline peter.mitchell

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Re: Fan replacement on the Rigol DP832
« Reply #2 on: March 23, 2014, 04:11:32 PM »
The noise from the DP832 fan, is from the fan itself, the "vvirrrrrr" kind of noise. Changing the fan to a lower RPM one just masks the problem - it moves the vibrational noise of the fan into a frequency range where it is hidden behind the sound of the turbulence.
You should be able to get a fan that doesn't make the "vvirrrrrr" noise but still moves the air. Be this due to better bearings, better balancing of the prop, a higher number of poles so the motors movement is smoother or tighter manufacturing tolerances.
 

Offline lapm

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Re: Fan replacement on the Rigol DP832
« Reply #3 on: March 23, 2014, 08:22:32 PM »
I suggest you seriously monitor device after those new fans. Their air flow is much lower then original ones and that may create heat issues... If your lucky, original ones were overpowered and new ones are enough, but anyways keep eye out on temperatures...
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Offline peter.mitchell

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Re: Fan replacement on the Rigol DP832
« Reply #4 on: March 23, 2014, 09:41:04 PM »
here are some fans i would suggest in order of preference

to replace the sunon 50 mm;

GELID Silent 5 50mm
12.9CFM, 23dB(A), 4000RPM nom. MTBF >50kH
Deepcool SF-500 50mm
9.6CFM, 23dB(A), 4500RPM nom. MTBF >???

and to replace the sunon 80 mm;

Noctua NF-R8 80mm Fan
31.2CFM, 17dB(A), 1800RPM nom. MTBF >150kH
Blacknoise NB-BlackSilentPRO P-P 80mm
31.7CFM, 18dB(A), 2000 RPM nom. MTBF >100kH
 

Offline ElektronikLabor

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Re: Fan replacement on the Rigol DP832
« Reply #5 on: March 24, 2014, 06:41:32 AM »
[...] it moves the vibrational noise of the fan into a frequency range where it is hidden behind the sound of the turbulence. [...]
Before changing the fan I thought about an silicone sleeve like this: http://www.amazon.com/gp/product/B003QKVRQC
How much does it help?

I suggest you seriously monitor device after those new fans.
Definitely I will! If I spot something strange, I will report it here :)
Rigol guarantees that this power supply can operate under full load in up to 40°C ambient temperature; I never get over 25°C in my room. Thats why I believe that this big fans are oversized in the most caces, but that is just an assumption :-//

here are some fans i would suggest in order of preference [...]
Thanks, I will keep that in mind as an backup!  :-+

BTW: What happens with DP832 in case of overheating? Do I get an error message on the display? Does the device monitor its internal temperature?
« Last Edit: March 24, 2014, 07:16:14 AM by medvedev »
 

Offline electronics man

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Re: Fan replacement on the Rigol DP832
« Reply #6 on: March 24, 2014, 07:43:51 AM »
did Rigol not fix the heat problem with that regulator
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Offline peter.mitchell

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Re: Fan replacement on the Rigol DP832
« Reply #7 on: March 24, 2014, 03:18:35 PM »
The gasket will not do much at all if you use it with the noctua fan, but with the stock fan it may help a little, but not a lot, the gasket will stop the vibrations coupling into the case and stop the things in the case from making noise, but it won't stop the fan from making noise. - that said, since the gasket is the price of the noctua fan, you should just buy the fan.

Note: Rigol current sense the fan to detect if it has failed or not, if the current consumption of your new fan isnt high enough, it will stop the outputs from operating. To resolve this, make sure at least 135ma is being drawn from the fan connection header.
 

Offline LaurentR

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Re: Fan replacement on the Rigol DP832
« Reply #8 on: August 25, 2015, 04:05:25 PM »
Old thread but...

I have a DP832 from fall-2014 and it seems to have only a 80mm fan in it. Is there a documented change at some point? Some posts mention just the 80mm fan, some other both a 50mm and a 80mm.

I just did a swap with a Noctua NF-A8 PWM, which has the most airflow and static pressure of all the Noctua (and other quiet) fans I found - including the NF-R8 mentioned above and in http://www.youtube.com/watch?v=b0kTXX8zXSo. It turns out that, despite the higher airflow and static pressure, that fan consumes less current than expected, so the 220R resistor in parallel mentioned in the YouTube video was not enough, and I had to move to a 150R (5W) resistor to keep the supply happy. Even that is not quite matching the Sunon (53mA Noctua + 80mA 150R < 145mA Sunon), but apparently, it is close enough.
 

Offline SaabFAN

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Re: Fan replacement on the Rigol DP832
« Reply #9 on: August 25, 2015, 10:41:09 PM »
Another way to make the fans quieter might be to add an LC-Filter to the Power-Rail, which is most likely PWM-Controlled. The annoying "virrrrrr" from the motor is caused by the rapid switching of the power supply. Did that in my brothers PC by adding a 2200µF capacitor to each fan connected to his fan-control. Works perfectly.

Online HighVoltage

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Re: Fan replacement on the Rigol DP832
« Reply #10 on: August 25, 2015, 11:04:18 PM »
I tried a different fan in the LeCroy 354 mentioned earlier in this thread and it did not work out at all!
The scope got hot and needed the high airflow.
Well, I reinstalled the old fan and sold the scope, it was just too noisy.

So, be careful on some equipment, it needs the high airflow.
May be the Rigol DP832 is one of these, I do not know.
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Offline ElektronikLabor

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Re: Fan replacement on the Rigol DP832
« Reply #11 on: August 27, 2015, 04:47:38 PM »
So, be careful on some equipment, it needs the high airflow.
May be the Rigol DP832 is one of these, I do not know.
Thanks for the warning; until now, I have no problems.
 

Offline SaabFAN

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Re: Fan replacement on the Rigol DP832
« Reply #12 on: August 27, 2015, 09:02:06 PM »
I think I mentioned this before, but just to be sure :)
There are Fan-Adaptors available, which effectively increase the diameter of the fan at the expense of some added length. If you have the space on the bench, you can add a 120mm fan this way, keeping the high air flow, but also making it really silent.

Offline julius79

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Re: Fan replacement on the Rigol DP832
« Reply #13 on: September 10, 2016, 09:15:47 PM »
    Hello gents , I just bought the DP832 and it's extremely annoying ,the fan noise , it's as i have a mill near by , i can't work like this !
So i have google for a silent fan and found this post .
I tried to replace the fan with the  https://www.quietpc.com/nf-a8-flx but this supply it's a " smart " one. The curent it's monitored, doesn't let me to use this fan.

Tried the method described by johndoe271828 on youtube and the fan speed its decreasing , i need the air out and to benefit the fan silences.

SO again like on many other things i went in to reverse engineering this part of the supply.The original fan it's consuming around 186 mA at maximum speed and 110 mA at lower speed. Apparently  has 2 modes , low speed and fast speed , i measure the voltage at both modes on R 44 which it's used as current sense resistor  . On first i have around 0.8 V on R 44 and 1.5 V on second speed.From my analysis the power supply doesn't control the RPM of the fan , just it's  making  sure it's running , and it's checking that by reading the voltage from U 15 TLC 072C OPAMP on FAN_FAIL test.
The new fan  Noctua NF-A8 FLX it's not hungry like the original one SUNON, it's needed just 48 mA to run at full speed . I have checked the voltage that is on the R 44 and it's not good , it's triggering the power management ic to show that messages on the screen about "fan fail " .
So did some math and calculate the value of the new current sense resistor R 44 with 48 mA at 1.5 V and i got around 32 Ohms . I have replace the R 44 with the closest that i had , a 27 Ohms at 2 W .
The fan it's running now with no prompt of failing fan and it's silent .
I mentioned that this power supply has 2 modes of running the fan , the first one it's around 8 volts where my fan it's fully silent and the second mode at 12 volt in full speed it's noise it's bearable . Now it's doing the job, taking the hot air out  in silence .
Please check the hand made electronic schematic of the fan circuitry of DP 832 if you wanna get silent . Some picture are attached too.
« Last Edit: October 09, 2016, 10:27:25 PM by julius79 »
 
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Offline raptor1956

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Re: Fan replacement on the Rigol DP832
« Reply #14 on: September 11, 2016, 11:29:22 AM »
The problem I have with just about all these quieting mods is that the fans they use to replace are quieter because they've been designed to run slower and move less air.  The modified unit will be quieter but it will also tend to run hotter because the fan doesn't move as much air.

It would be nice of the component makers used larger fans than can be run slower, but they don't and they don't provide the room to install a larger fan so you're stuck switching one 80mm fan for another 80mm fan.

What might work is stacking two of the quiet fans on top of one another to increase flow rate and current draw for the fan, but, once again, they don't tend to have the room to do that.  Alternatively, picking a fan that's a bit thicker, 20mm versus 15mm for example, so that even if they run slower and therefore quieter the volume of air moved will be much closer.

Sadly there are not a great many fans of a given size that come in several different thicknesses and doubling them requires the room to do so...


Brian
 

Offline invzim

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Re: Fan replacement on the Rigol DP832
« Reply #15 on: February 01, 2017, 12:12:17 AM »
Great info here, just modded my DP831 with a Noctua NF-A8 PWM.  A 150 ohm 3w resistor in parallel did the trick.

I took one of the adapter cables that came with the Noctua and made this contraption, works great :)


 


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