DHO1074 horrible fan noise - Page 1
Forum section: electronics / testgear

author: brandmeist3r
author_rank: Newbie
timestamp: October 05, 2024, 12:22:33 pm
content: Hi there,I just got my new DHO1074 fresh out of the box directly from Rigolshop EU and I am a little disappointed.So far I have not found any topic regarding the fan noise, so I made a quick video.The fans are so loud, that working without headphones is not possible.https://youtu.be/TvXG3V9IeCQ@EEVblog Dave if you want to include the video or parts of it, you may do so.I will tear it down, check out the fans and update the post later.Anyway, what replacement fans should I get? Thinking of Noctua.How was your first experience with the new DHO1000 series?

author: ebastler
author_rank: Super Contributor
timestamp: October 05, 2024, 12:48:37 pm
content: Yes, the fans are very loud indeed -- especially considering that the enclosure is large and would have room for a large, slow-running fan. My first impression after powering up my new DHO1074 last year was "Ready for lift-off!".I decided to return the scope, mostly for other reasons. But there is a way to make it noticeably quieter via a software change only -- the fans have PWM control, Rigol just does not use it:https://www.eevblog.com/forum/testgear/hacking-the-hdo1khdo4k-rigol-12-bit-scope/msg5231181/#msg5231181(You can also look into installing quieter fans of course. But that's probably not something you want to do right away, in case you decide to return the scope or need a warranty repair. The software modification is easily reversible.)Edit: There are multiple temperature sensors on the main board which can be read via a dialog in the Utility (?) menu. So you can check temperatures before & after reducing the fan speed to make sure the scope is still in a healthy state.

author: brandmeist3r
author_rank: Newbie
timestamp: October 05, 2024, 01:35:35 pm
content: Yeah, ready for liftoff is the right description, it sounds like the bearings are broken.I will try to adjust them via PWM first, thanks for pointing me in that direction.Really a bummer, that the warranty will get void if opening the case. I might swap the fans later tho.

author: NE666
author_rank: Frequent Contributor
timestamp: October 05, 2024, 01:51:00 pm
content: It's not quiet but honestly, this is lab equipment and not the latest ipad, PC or consumer electronics item. People should hold expectations accordingly.

author: brandmeist3r
author_rank: Newbie
timestamp: October 05, 2024, 01:54:14 pm
content: Agreed, but I have never experienced such loud lab equipment and I did not have that expectation.I also have previous experience with industry test equipment, never had such a loud unit.Also, in the video it is not as loud as irl, I guess my iPhone did some suppression there.

author: ebastler
author_rank: Super Contributor
timestamp: October 05, 2024, 02:27:17 pm
content: Quote from: NE666 on October 05, 2024, 01:51:00 pmIt's a lab instrument which one spends considerable time sitting directly in front of, trying to concentrate and debug a circuit. Given its form factor and power consumption, the DHO1000 is really unnecessarily and recklessly loud.

author: Bryn
author_rank: Regular Contributor
timestamp: October 05, 2024, 02:40:30 pm
content: And I thought the fan of the GPU of my old computer was bloody loud... only because dust got to it badly.Anyway, when I first saw this thread, I immediately assumed that it was used, hence the loud noise it made. Are those fans meant to be this noisy though?

author: skander36
author_rank: Frequent Contributor
timestamp: October 05, 2024, 02:45:03 pm
content: @brandmeist3r, this is not the normal sound for DHO1074.You have some wire touching one of the fans or something broken on one of them. There are two fans.The noise from the fans is indeed loud but definitely not this one. You should return it for checking.LE - added short recording of the noise.https://youtube.com/shorts/VyzlZJoBHtI

author: ebastler
author_rank: Super Contributor
timestamp: October 05, 2024, 03:50:57 pm
content: Ouch -- I had not watched the video before since "DHO1074 = too noisy" was firmly on my mind anyway... But indeed, that whirring noise is not normal; sounds like a wire or metal/plastic shaving touching the fan blades.

author: brandmeist3r
author_rank: Newbie
timestamp: October 06, 2024, 06:40:59 pm
content: Update: It is the bearings, if I rotate the scope during movement the noise goes almost away.I also checked with a screwdriver and the fans can rotate freely.Anyway, I will send it back to Rigol and post a followup about the support experience.

author: brandmeist3r
author_rank: Newbie
timestamp: October 07, 2024, 08:23:11 pm
content: Update 2: I visited my makerspace and dropped it inside my bag from a bench accidentally and it must have been a cable. The noise is finally gone

author: 2N3055
author_rank: Super Contributor
timestamp: October 07, 2024, 09:51:37 pm
content: Quote from: brandmeist3r on October 07, 2024, 08:23:11 pmThat means it definitely a warranty return, because there is something inside the scope that is loose..

author: skander36
author_rank: Frequent Contributor
timestamp: October 07, 2024, 09:57:54 pm
content: Quote from: 2N3055 on October 07, 2024, 09:51:37 pmAnd just because the stupid Chinese habit to seal the devices you couldn't check for yourself ...

author: Someone
author_rank: Super Contributor
timestamp: October 07, 2024, 10:06:05 pm
content: Quote from: 2N3055 on October 07, 2024, 09:51:37 pmArent the loose cabling (not tied off/retained) in the teardown? Just normal?

author: 2N3055
author_rank: Super Contributor
timestamp: October 07, 2024, 10:49:30 pm
content: Quote from: Someone on October 07, 2024, 10:06:05 pmAnd how do you teach them it is not all right to do that?By returning stuff that rattles.

author: thm_w
author_rank: Super Contributor
timestamp: October 07, 2024, 10:56:48 pm
content: 3:35 does look like the cables should have been tied back better:youtu.be/qEpkVa_ysaw?t=215Quote from: 2N3055 on October 07, 2024, 10:49:30 pmThats fine but its just a waste of time if the scope is working fine now. And you risk getting a more beat up scope back, etc.I know because I've done it for similar issues, I guarantee no one cares that one device was returned.

author: 2N3055
author_rank: Super Contributor
timestamp: October 07, 2024, 11:45:59 pm
content: Quote from: thm_w on October 07, 2024, 10:56:48 pmWe are sharing our thoughts on the matter. That is what I would do. That is all.Or open it and check. Just hoping that it is Ok now does not work for me.. Just how I am..

author: Fungus
author_rank: Super Contributor
timestamp: October 08, 2024, 07:32:59 am
content: Quote from: brandmeist3r on October 07, 2024, 08:23:11 pmI was going to suggest doing this but you beat me to it.