Siglent SDS1104X-E noisy fan replacement

[balnazzar]

And consider that I work regularly in a lab with many scopes, multimeters and AWGs (~20 stations, mainly Siglent stuff, but some old Agilent/HP things too).

My 1104x-e would be by a far stretch the noisiest device in there.

[tautech]

Is there something seriously wrong with your notebook? I wouldn't call the SDS1104X-E noisy by test equipment standards, but those standards are pretty low. I have an X220 beside the scope right now, and the scope completely swamps the notebook.

It's something in between a hair dryer and a vacuum cleaner. I regularly use SDS5000s and they are *much* more silent than the 1104x-e.

SDS6000A are even quieter again ! 

From my experience with small fans, if you run them at 9V rather than 12V, the difference in airflow and static pressure won't be dramatic, but the difference in acoustical noise could be substantial.

Actually with all the concern over 4ch X-E fan noise I'm surprised no one has done a fan controller PCB with a temp sensor, picking supply from the fan header and supplying the fan from the controller PCB.

What would ppl pay for such a controller ?

[BillyO]

Now I'm really thinking that maybe I got a defective 1104x-e specimen.

Does it vibrate at all?  I once had a PC power supply that had a fan with a small piece missing from one blade.  It made enough vibration that there were strange sounds coming from nearly everything in the PC.

[BillyO]

I just did a little test.  Turned everything off in the lab then did a sound test on the UNI-T and the Siglent.  The UNI-T was 6dB louder than the Siglent.  That is quite a bit.  The Siglent was just under 3dB louder than the Lenovo X230 notebook with the X230 blowing as hard as it could.  So it is noticeably louder than the notebook, but very much quieter than the UNI-T.  The UNI-T sound is not only louder but has more high frequency noise so it even more annoying.

Anyway, I guess I'm just used to working in noisy environments as the noise it makes is generally not noticeable to me when things are normal (lots of stuff blowing).  Maybe I'm going deaf.

[balnazzar]

Now I'm really thinking that maybe I got a defective 1104x-e specimen.

Does it vibrate at all?  I once had a PC power supply that had a fan with a small piece missing from one blade.  It made enough vibration that there were strange sounds coming from nearly everything in the PC.

It doesn't vibrate at all.

[coppice]

I just did a little test.  Turned everything off in the lab then did a sound test on the UNI-T and the Siglent.  The UNI-T was 6dB louder than the Siglent.  That is quite a bit.  The Siglent was just under 3dB louder than the Lenovo X230 notebook with the X230 blowing as hard as it could.  So it is noticeably louder than the notebook, but very much quieter than the UNI-T.  The UNI-T sound is not only louder but has more high frequency noise so it even more annoying.

Anyway, I guess I'm just used to working in noisy environments as the noise it makes is generally not noticeable to me when things are normal (lots of stuff blowing).  Maybe I'm going deaf.

The fans in the Uni-T scopes I've used seem to get the chassis into resonance, which can be quite unpleasant for long periods.

[sja]

Tautech:

What about something like these cheap fan controllers: https://www.aliexpress.com/item/4000120607047.html?spm=a2g0o.productlist.main.5.3e033c8bpmZxY2&algo_pvid=6ce9d057-c345-46c6-bd57-ee2536774044&algo_exp_id=6ce9d057-c345-46c6-bd57-ee2536774044-2&pdp_ext_f=%7B%22sku_id%22%3A%2210000000332499657%22%7D&pdp_npi=2%40dis%21EUR%213.35%212.88%21%21%211.72%21%21%402100b1a616664275073707418d0764%2110000000332499657%21sea&curPageLogUid=gWuAS4LC4PNt

I have only used them in manual mode to provide cooling for devices without fan headers.

In the model that I have, the temp sensor cable is 9.5 cm from the tip to the top of the connector. Would that be long enough?

[tautech]

Tautech:

What about something like these cheap fan controllers: https://www.aliexpress.com/item/4000120607047.html?spm=a2g0o.productlist.main.5.3e033c8bpmZxY2&algo_pvid=6ce9d057-c345-46c6-bd57-ee2536774044&algo_exp_id=6ce9d057-c345-46c6-bd57-ee2536774044-2&pdp_ext_f=%7B%22sku_id%22%3A%2210000000332499657%22%7D&pdp_npi=2%40dis%21EUR%213.35%212.88%21%21%211.72%21%21%402100b1a616664275073707418d0764%2110000000332499657%21sea&curPageLogUid=gWuAS4LC4PNt

I have only used them in manual mode to provide cooling for devices without fan headers.

In the model that I have, the temp sensor cable is 9.5 cm from the tip to the top of the connector. Would that be long enough?

Depends on where the sensor is best to be located as there are a # of things to be considered:
PSU heat and the need to keep its caps cool.
Mainboard temps, to keep operating temp stable (after warm up) and system accuracy temperature stable.
Cooling the FPGA in particular where all the hard work goes on and it's the only device sporting a heatsink.

To do this properly it's within the realms of a thermal engineer and temp stable environs so to test different ambients to see how well the cooling system can keep the system temps stable.

By far the simplest solution is to throttle back the fan a little to reduce noise by how much, that is the issue.
I don't have the equipment to test temperatures accurately and all the locations needed and the fan adjustment could be quite simple with a 1W wirewound pot as we are only dealing with ~60mA fan current.
Maybe a 200 Ohm pot has the range to make adjustments.

A noncontact RPM meter can give us a OEM measurement and post mod measurement that we should be able to correlate to fan charts for flow and pressure results that might also point toward a better fan replacement.
It's just not a 5 minute job to do properly.

[chemary]

I bought this scope 4 years ago, it's a great scope more than enough for my hobby projects but it's loud fan is really annoying (sometimes I want to leave the data-logging overnight but my flat is small and I have it close to my bed).
While trying different solutions I noticed that closing the plastic enclosure increases the noise. The air exhaust is really bad designed as it's partially obstructed by the plastic enclosure and probably it creates some turbulence that increases noise. I have put some anti-vibration foam between the metal and the plastic and the noise has drop a little, I have not measured it so it's just my impression.

I tried different fans I have lying around from old computers but the original is by far the less noisy, then as suggested on this forum I was trying different fan voltages I added two 1N4148 diodes to drop the voltage 1.2V as it's hot where I live and dropping the voltage to 9V seems too much.

[LogicalDave]

@chemary Did the two diode-drops reduce the noise significantly?

[chemary]

Yes @LogicalDave, the noise now is still audible but tolerable.

[tjookum]

Sorry for digging up this old thread. Since the beginning of owning my SDS1104X-E I have always been annoyed by the fan noise. It's not overly loud but just generally annoying for a small home lab and I found myself switching it off as soon as I could in between measurements.

Well, fast forward almost 4 years and since I well and truly own this piece of equipment now I decided to do something about it.

It’s been a while since the last post but I hope this might be of use to some.

After a few months  I finally gave up and opened the scope. My idea was to measure critical temperatures and characterise the fan performance based on its voltage – when the scope is fully closed. I attached 3 probes (DS18S20) to the power supply heatsink, FPGA heatsink, and one “loose” inside the case. The probes are attached using double sided heatsink thermal tape, which is quite strong. Additionally, I placed one more probe a few cm from the inlet fan.

Next, I hooked up the SLA1016 logic analyser to give the setup more power draw. I also switched all channels, analog and digital on.
I programmed the SPD3303 to 5 1h slots. Started with 8V increasing it by 1V every hour. Below you can see the graph. I also attached the scope placement. There is not much air movement in the corner.

Looking at the data I take it’s safe to under-volt the fan. I believe I’ve read the operating temperature is up to 40 deg. Here in North-East England, where I live there is rarely above 25 deg outside. Plenty of headroom in my view.

I’m settling with powering the fan with 9V. The noise is much-much lower and bearable. I can barely hear it and it’s not annoying. Besides, it's easy to stick a standard, linear regulator without risking noise from a buck regulator.

I’m planning to do similar experiment with the SDM3055 and STD1062X soon. Can’t stand them fans!

P.S.
I just spotted a mistake. The last slot should be 9V.

After seeing the excellent post by AdiGital, I added a LM7809 on a small board with some JST XH connector so it is easily revearsable. There is plenty of space next to the fan so I mounted it with some high strength double sided tape. It rarely gets above 30C here and when it does both me and my trusty SDS1104 will be out of commission anyway.

The fan is still audible but sounds a lot more like a normal PC idling instead of the RGB gamermode beast it was before. I can definitely recommend it if your SDS1104 is out of warranty anyway and you don't live in a tropical climate. Thanks to AdiGital for doing the measurements and giving me the confidence to do something I should have done years ago.