Author Topic: DP832 - Fan Replacement 2018 (Read 10272 times)

Gandalf_Sr · « **on:** March 16, 2018, 10:53:13 am »

After working with my new DP832 this week, I decided that the fan was sooo noisy that it had to go. I googled and found this blog/website describing how to switch the noisy Sunon Maglev ME80251v1-000C-A99 fan for a Noctua NF-R8 redux 1800; I got the fan and a 2W 27 Ohm resistor and did the change yesterday. A few comments and then some pictures...

It's a pain to change as you have to take the PSU apart - take lots of pictures showing where all the different plugs go before unplugging everything.

The link I posted above says that the old resistor that measures the fan current (R44) is 15 $\$\Omega\$$ but mine was only 7.5 $\$\Omega\$$ which worried me a bit but he also lists the current drawn by his Noctua as 110 mA - the one I got was only 60 mA and still claims 53.3 m³/Hr. My calcs were that 7.5 $\$\Omega\$$ x 0.15 A = 1.125 V (old) and 27 $\$\Omega\$$ x 0.06 A = 1.62 V (new) so I would have been better with a 19 $\$\Omega\$$ resistor but I figured that the OpAmp that was checking the voltage probably didn't care about 1.62 vs 1.125 volts so I stuck in my 27 $\$\Omega\$$ resistor.

My new fan had 4 wires so I cut the plug off the old fan and connected the new fan to that 2 pin connector (black is 0V and yellow is +12V).

I put it back together and powered up, it seems to work perfectly - no failed fan messages when I turn the outputs on - and the fan is almost inaudible now - it does the short burst of full speed on start up and I can tell that it has quite some capability if it needs to move air. I live in Michigan so the DP832 is likely going to never see more than 90 degrees F ambient and only 72 indoors.

Pictures:
Old Fan
New Fan fitted
R44 (in red box)
System Info showing no-load temp (get that detailed view by viewing the ordinary system info and then pressing buttons under screen (numbers from L to R) 1 - 3 - 2)

taydin · « **Reply #1 on:** March 16, 2018, 11:00:54 am »

Thanks for this info, my DP832A is also starting to get on my nerves with its constant fan noise. Might change mine, too, if I can find this nice fan, that is ...

Gandalf_Sr · « **Reply #2 on:** March 16, 2018, 12:01:45 pm »

I bought my fan from Amazon https://www.amazon.com/gp/product/B00KF7MVI2/ref=oh_aui_detailpage_o03_s00?ie=UTF8&psc=1

Just out of curiosity, what is your fan temperature with no load? (follow 1-3-2 steps above) I didn't record mine before I did the modification.

PTR_1275 · « **Reply #3 on:** March 16, 2018, 03:22:54 pm »

Did you do anything to get the bottom half of that screen showing? (With the temperature)

My dp832 shows the first 3 lines, but it’s fw 00.01.14

JDubU · « **Reply #4 on:** March 16, 2018, 06:02:50 pm »

I can answer that:

Press Utility > SysInfo > M1, M3, M2
where "M1" is is the left-most button on the bottom of the display.

taydin · « **Reply #5 on:** March 18, 2018, 07:02:51 pm »

Mine doesn't show temperature, either. Just device model, serial number and digital version, which is 00.01.13

Gandalf_Sr · « **Reply #6 on:** March 18, 2018, 07:57:39 pm »

When you are seeing the 3-line System Info do this...

Press M1, M3, M2 (where "M1" is is the left-most button on the bottom of the display) and the extra information will magically appear.

taydin · « **Reply #7 on:** March 20, 2018, 03:05:03 am »

Ok that worked. Immediately after turning on my 832A, the temperature is 28.9 celsius.

Gandalf_Sr · « **Reply #8 on:** March 20, 2018, 11:13:52 pm »

Cool, so you have the same temperature reading as I do. I have run it at about a 100W and it was quiet and cool

bson · « **Reply #9 on:** March 21, 2018, 03:30:43 am »

Interesting, my DP832 non-A doesn't have the temperature readout...

Edit: never mind, I did a firmware update to 1.14 and I now have it, too.

Wolfgang · « **Reply #10 on:** September 30, 2018, 12:59:00 pm »

I started an opinion poll about the RIGOLs

https://www.eevblog.com/forum/testgear/what-is-your-opinion-of-the-quality-of-the-rigol-dp832(a)/msg1856247/#top

Please give a rating of your own experiences with this stuff - good or bad, whatever it may be.

Thanks
Wolfgang

Pinkus · « **Reply #11 on:** August 13, 2019, 01:31:58 pm »

I have finally found time to replace the fan of my DP832.... the volume of the fan noise was always annoying me.
Though a surprise was waiting:

I wanted to replace it with the above mentioned Noctua, thus I purchased one for about 10 Euros.
But during the conversion I noticed that it was not necessary at all, these 10 Euros can be saved.

1) The Noctua allegedly has the same air performance as the original Sunon fan, but subjectively it produces much less air. It rotates with 1600 rpm where the original Sunon runs with 3200 rpm.

2) The fan cover on the back of the DP832 covers approx. 50% of the surface, i.e. the fan has to produce an unnecessary amount of power to squeeze the air out of the small openings.

Here I thought, to compensate the lower air pressure of the Noctua I would just remove the fan cover of the back of the DP832.
Therefore I separated the fan cover with a Dremel and replaced it with a thin grille cover. The reason was so that the Noctua fan could produce about the same air performance (without the fan cover) as the Sunon (with the fan cover) due to the lower air resistance.

First try: original Sunon fan without the fan cover ..... and ..... whow! The whole unit is 10dB quieter, so it's only half as loud as before! Just by removing and replacing the fan cover. Probably due to the eliminated turbulence at the sharp corners of the cover and of course of the removed extra resistance.

2nd step: Since the air resistance now has become much smaller by removing the cover, the original fan can now turn slower for the same amount of air. A 47 Ohm resistor in series makes the DP832 very very quiet with approximately the same amount of air running through the electronics. In fact, it is that quiet now, that the DP832s chirping display illumination is disturbing.

Well, since I had the 90mm Noctua fan already purchased, I now installed it together with the 3D printed adapter from Thingiverse I already printed. Result: the DP832 is now almost inaudible (but the display).
Note: since this fan needs less power and the DP832 gives an error message, I had to connect 220 Ohm in parallel to the fan.

So, long story short: save your money, you don't need a new fan. It is sufficient to remove (Dremel) the fan cover to lower the volume already by 50%. If you want to make it even quieter, solder a 47 Ohm resistor in series with the fan (you might need to connect the mentioned 220 Ohm resistor in parallel to the fan connector).

Edit:
Temperature:
(see post above how to switch on the temperature display).

Idle (no load): 30.5°C after some time
90W load (* see below): 76°C after 2 hours
after switchoff the load (=idle) and 5 min. waiting time: back to 55°C

*= I set channel 1 and channel 2 to 15V and 3.2A; I then connected them serially (30V, 3.2A max) and used an electronic load to draw 3A. I let it run for >2 hours.

Vaiti · « **Reply #12 on:** August 14, 2019, 07:16:11 am »

Quote from: Pinkus on August 13, 2019, 01:31:58 pm

I wanted to replace it with the above mentioned Noctua, thus I purchased one for about 10 Euros.

Little confused. The fan mentioned here is a 80mm, Noctua NF-R8 redux-1800. If I understood correctly, this fan doesn't require an adapter as it is the same size as the Sunon already in the rear of the DP832.

But you have a 90mm that needs the adapter? Which fan model are you using?

Pinkus · « **Reply #13 on:** August 14, 2019, 07:51:12 am »

Sorry for the confusion. I purchased a Noctua NF-B9 redux-1600 because it was mentioned in another DP832 thread.
This is a 90mm fan where you need an adapter for.

But as I said above, today I would rather just remove the original fan cover and just buy a 1$ replacement for the cover (eg. here: https://www.aliexpress.com/item/32888214967.html) and then use the existing fan.

Other:
Link to thingiverse: https://www.thingiverse.com/thing:2994987

Check also this link regarding noise / airflow of different fan grill (cover) styles: https://www.pugetsystems.com/labs/articles/Effects-of-Grill-Patterns-on-Fan-Performance-Noise-107/. After reading this, you will stay away of any sort of fan grill but the wire-grill.

JDubU · « **Reply #14 on:** March 21, 2020, 03:43:28 pm »

I finally got tired of the unbearable fan noise on my DP832 and did the replacement. It is now really, really quiet. Just the soft sound of moving air.
I cut out the existing fan grill with tin snips and a sheet metal "nibbling" tool and replaced it with a wire grill plus a rubberized sheet metal edging strip to smooth the airflow at the edge of the cutout. A parallel 250 ohm 2W resistor was also added to avoid the Rigol fan fail error message (actually eight parallel 2K ohm 1/4 W resistors because I already had them).

Here are the replacement parts:

Fan: Noctua NF-R8 redux-1800
Replacement grill: https://www.amazon.com/gp/product/B016N6X06K/ref=ppx_yo_dt_b_asin_title_o05_s00?ie=UTF8&psc=1 (needs longer, 3/8" screws that I already had)
Edging strip: https://www.amazon.com/gp/product/B07BPCB8WH/ref=ppx_yo_dt_b_asin_title_o02_s00?ie=UTF8&psc=1 (really nice stuff -- need to cut it with tin snips since it has metal clips inside)
Connector: https://www.amazon.com/gp/product/B07V2XSJZ6/ref=ppx_yo_dt_b_asin_title_o01_s00?ie=UTF8&psc=1 (JST-XH 2 pin -- Caution: the color of the red/black wires are reversed compared to the original fan wiring)

Gandalf_Sr · « **Reply #15 on:** March 21, 2020, 04:23:48 pm »

Looks good, didn't you want to change the big resistor on the PCB?

JDubU · « **Reply #16 on:** March 21, 2020, 04:31:03 pm »

Quote from: Gandalf_Sr on March 21, 2020, 04:23:48 pm

Looks good, didn't you want to change the big resistor on the PCB?

I would have preferred to do that, but I didn't want to take everything apart to get good enough access to it.
Also, I wanted to be able to put the original fan back in easily if the replacement didn't work out (e.g. not enough air flow).

klausES · « **Reply #17 on:** March 21, 2020, 04:40:13 pm »

If you remove the grill from the sheet metal of the back wall
(a good move and nicely protected the cut edge)
you should turn it over right away.

The sheet metal cross was the only reason that was justified to have the fan sucked out of the housing,
since the stall noise (if the suction side is close to a sheet metal cross) would have been much louder.

Since this unfavorable circumstance no longer exists, it would be more favorable in terms of flow technology to blow the heat sink.

Even if e.g. the PTC / NTC sits further forward or even in the front for measurement and thus shows a lower temperature of fresh air drawn in
(housing under negative pressure) (this would only be obviously better)
the actual effective temperature is reduced when the air is blown (upside down fan) inside and on the components.

Since the temperature difference between the outside air and the heat sink is decisive here,
the amount of heat that is dissipated when the outside air that is not preheated is blown in is really higher.

JDubU · « **Reply #18 on:** March 21, 2020, 04:46:16 pm »

Quote from: klausES on March 21, 2020, 04:40:13 pm

If you remove the grill from the sheet metal of the back wall
(a good move and nicely protected the cut edge)
you should turn it over right away.

The sheet metal cross was the only reason that was justified to have the fan sucked out of the housing,
since the stall noise (if the suction side is close to a sheet metal cross) would have been much louder.

Since this unfavorable circumstance no longer exists, it would be more favorable in terms of flow technology to blow the heat sink.

Even if e.g. the PTC / NTC sits further forward or even in the front for measurement and thus shows a lower temperature of fresh air drawn in
(housing under negative pressure) (this would only be obviously better)
the actual effective temperature is reduced when the air is blown (upside down fan) inside and on the components.

Since the temperature difference between the outside air and the heat sink is decisive here,
the amount of heat that is dissipated when the outside air that is not preheated is blown in is really higher.

Good points.
I'll give it a try.

timber23 · « **Reply #19 on:** March 26, 2020, 07:41:18 pm »

Quote from: JDubU on March 21, 2020, 03:43:28 pm

I finally got tired of the unbearable fan noise on my DP832 and did the replacement. It is now really, really quiet. Just the soft sound of moving air.

Thank you for presenting your modification and the part list. After my first test I wondered that the fan did not work at all... As you mentioned red and black are swapped...
For comparison I measured the sound level before and after the modification. I can still hear the fan. It is still loud from my point of view. Maybe I have to put a resistor in series reduce the voltage and rpm a little bit? The idle temperature rises to about 27.5 °C after 10 minutes. As suggested I changed the airflow direction to blow inside the device.
Some pictures the process:

JDubU · « **Reply #20 on:** March 26, 2020, 08:30:34 pm »

I tried turning the fan so that it blew inward and it definitely lowers the internal temperatures compared to the fan blowing outward.
However, it is also a bit louder when blowing inward and adds a high pitch whine, caused by the wire fan guard, which I find to be nerve-wracking. I switched it back to blowing outward and it is currently the quietest fanned instrument on my bench. I figure that I can always turn it back around if the need arises. Meanwhile, I will leave the DP832 over temperature protection (OTP) enabled.

klausES · « **Reply #21 on:** March 26, 2020, 10:41:04 pm »

Quote from: JDubU on March 26, 2020, 08:30:34 pm

...However, it is also a bit louder when blowing inward and adds a high pitch whine, caused by the wire fan guard, which I find to be nerve-wracking...

This is the typical problem when formations are close to the suction side.
This can range from stalling noises to vibrations of the air column (between the obstacle and the wings).

Try to place the fan further in with distances into the housing (preferably rubber ones for decoupling,
10mm may be enough), or you can try to move the grid 10mm further out (with spacers).

eutectique · « **Reply #22 on:** April 02, 2020, 05:42:51 pm »

Got my DP832 recently and stumbled across this thread.

Just for the record, Noctua has two versions of NF-R8 redux-1800 fans: PWM (4-pin) and non-PWM (3-pin). They differ in current consumption, other characteristics are the same.

Sunon Maglev ME80251	145 mA
NF-R8 redux-1800	110 mA
NF-R8 redux-1800 PWM	60 mA

Non-PWM version is quite close electrically to the original fan and probably wouldn't need a different resistor.

JDubU · « **Reply #23 on:** April 02, 2020, 06:14:32 pm »

Quote from: eutectique on April 02, 2020, 05:42:51 pm

Got my DP832 recently and stumbled across this thread.

Just for the record, Noctua has two versions of NF-R8 redux-1800 fans: PWM (4-pin) and non-PWM (3-pin). They differ in current consumption, other characteristics are the same.

Sunon Maglev ME80251 145 mA
NF-R8 redux-1800 110 mA
NF-R8 redux-1800 PWM 60 mA

Non-PWM version is quite close electrically to the original fan and probably wouldn't need a different resistor.

I used the Noctua 3 pin version. Measured current draw in open air was 95mA at 12V. The specs are for max current draw.
Didn't measure the existing Sunon current draw, but here is a video where it was measured in open air to be about 160 mA: https://www.youtube.com/watch?v=b0kTXX8zXSo. (time 3:35)

I did not try the Noctua in the DP832 without the parallel 250 ohm resistor.

timber23 · « **Reply #24 on:** April 02, 2020, 08:05:23 pm »

Quote from: JDubU on April 02, 2020, 06:14:32 pm

I did not try the Noctua in the DP832 without the parallel 250 ohm resistor.

I tried it. It doesn't work. When you switch on a channel than it will be automatically disabled. Furthermore the system test procedure shows that fan fails. That is why I added the parallel resistor. I have the 3-pin version as well.


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Author Topic: DP832 - Fan Replacement 2018 (Read 10272 times)

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