Agilent 3000X Acoustic Noise? (not the fan) - Page 1
Forum section: electronics / general

author: PaulStoffregen
author_rank: Newbie
timestamp: December 19, 2012, 01:30:41 am
content: I recently rented an Agilent DSO-X 3014A scope (planning to buy a 3000X or 4000X soon, but wanted to try it for a while first). It's awesome, but noisy!As a quick test, I carefully poked tweezers in to stop the 3014's fan for several seconds. It turns out much of the noise is not the fan at all. It sounds somewhat like a switching power supply going bad. Maybe I ought to make an audio recording?Can anyone here with an Agilent 3000X scope confirm if their scope is silent when the fan is stopped, or if this noise is "normal"? Maybe this unit is failing (and I ought to return it to the rental shop before it goes out)?

author: Psi
author_rank: Super Contributor
timestamp: December 19, 2012, 02:26:59 am
content: If it requires a super quiet room to hear it, or you have to put your ear close, then its probably not something to worry about and just normal operation.However, if it's very noticeable then there's something wrong (either in the design or in the unit you have).It could be something as simple and harmless as missing silastic on some inductorsOr it could be a sign of extra strain on the supply due to bad caps etc.Since it's a rental it would be best that it not die while you have it. (they might claim you broke it)So there are two options1) Return it2) Call them up and report that it's working fine but you can hear a noise that sounds abnormal. Then ask what they want to do.If they choose to do nothing then it's not your fault if it dies later. (if you're really paranoid you could record the phone call)

author: vvanders
author_rank: Regular Contributor
timestamp: December 19, 2012, 02:52:31 am
content: I don't have a totally quiet room but I never noticed any noise from it(DSOX3014A here).

author: TorqueRanger
author_rank: Frequent Contributor
timestamp: December 19, 2012, 03:07:07 am
content: Quote from: Psi on December 19, 2012, 02:26:59 amIf you do this I would definitely record it so it can't come back and bite you...

author: mkissin
author_rank: Regular Contributor
timestamp: December 19, 2012, 05:53:57 am
content: Actually, it is a switching power supply. It's a known problem.http://cp.literature.agilent.com/litweb/pdf/DSOX3014A-03.pdf

author: EEVblog
author_rank: Unknown
timestamp: December 19, 2012, 09:22:29 am
content: Quote from: mkissin on December 19, 2012, 05:53:57 amSomeone always knows the answer!That's why I love this forum.Dave.

author: Baliszoft
author_rank: Frequent Contributor
timestamp: December 19, 2012, 10:06:15 am
content: I also had a similar issue. Check my video here:https://www.eevblog.com/forum/chat/noise-problem-on-agilent-oscilloscopes/60/

author: PaulStoffregen
author_rank: Newbie
timestamp: December 19, 2012, 01:26:44 pm
content: Thanks, especially for the link to that service note! Yup, that's exactly the same sound I'm hearing from this scope. I'll call the rental place tomorrow.The 3000X fan still seems pretty substantial. Does anyone know if the 4000X scopes are quieter? I intend to use this in an extremely quiet room.

author: PaulStoffregen
author_rank: Newbie
timestamp: December 19, 2012, 09:46:03 pm
content: I called the rental place. A technician called back 10 minutes later. I described the problem. He's sending a replacement scope today, and a pre-paid box to send this one back.