Rigol MSO5074 slight ticking/screeching sound?

[Tommy_Vercetti]

Hello Everyone, I just received my MSO5074 and was able to upgrade it in less than 5 min thanks to the excellent work of all the posters on this forum. I had one question, I noticed that the scope makes a very slight ticking sound that kind of borders on minor screeching when running - its barely noticeable, about as loud as an old school hard disk drive, maybe even quieter. I noticed that if I turn on and off the channels or change the V/div, the sound pauses for a moment as the waveform refreshes on the screen. The sound also varies slightly depending on the V/div I am on. I noticed this even before the upgrade. Is this normal?

[Anding]

My MSO5104, also new, does not have this symptom.

[Tommy_Vercetti]

Thanks for the response. I noticed that It only happens at time divisions 5us and less. I am wondering if I should return it in exchange for another one.

[Tommy_Vercetti]

I managed to get a recording of it. Its in the attached MP3, but you can here it...sort of sounds like bugs in the summer night. You can sort of hear me toggling a few of the scope buttons and the sound pausing for a moment when I do that.

[Tommy_Vercetti]

My best guess is that it's coming from the power supply - since I believe its coming from that back left corner, but I am not 100% sure.

[Anding]

Can you try the scope in different locations on different outlets?  Run it overnight with the noise and see if it gets better or worse?  Test with no inputs connected?  Press the “default” button or find a reset in the utility menu?

[Tommy_Vercetti]

Ya I just tried another outlet downstairs in my house…same behavior. I still have to do the self cal after patching the firmware. But I did notice this issue before I upgraded.

[skander36]

I have also noticed this sound on my 3 years old 5074 from time to time. I do not mind it.

[Fungus]

Sounds like a noisy ceramic capacitor to me.

https://www.google.com/search?q=noisy+ceramic+capacitor

[Tommy_Vercetti]

Yah I constantly hear it when the time division is less than 5us. My main concern is that it might influence the accuracy of the measurements. I am probably going to try to reinstall the stock firmware on the scope and exchange it via amazon.

[2N3055]

Yah I constantly hear it when the time division is less than 5us. My main concern is that it might influence the accuracy of the measurements. I am probably going to try to reinstall the stock firmware on the scope and exchange it via amazon.

Why would it have influence on measurements?
FW should have no influence on it. Also you need new FW for bug fixes..
That is a faint sound of ceramic capacitor or a coil in switcher on board. When scope is doing sweeps it changes current consumption and modulates the sound.
There is good chance all of them make that sound or all the ones in a single manufacturing batch do. Is it really that annoying it warrants return? You night return it and get replacement on with same sound.

[Tommy_Vercetti]

Yes, I know that the FW has no influence on it since the sound was present before I installed the new FW. I was mentioning that I need to put the factory FW back on if I wanted to return it. I am weary of any kind of sound coming from the power supply and I am worried that it might contribute to different or common mode noise that can influence the accuracy of the measurements. It is also very annoying to hear. I primarily wanted to post to see if anybody else has that issue.