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Thread: Noise problem on Agilent oscilloscopes


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Baliszoft


Posts: 14
Registered: 02/09/12
Re: Noise problem on Agilent oscilloscopes
Posted: Feb 9, 2012 11:52 AM   in response to: Coris in response to: Coris
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Hi There!

I just bought a 2000 series MSO and what i am concerned about is its audible noise (not signal noise). I can hear the sound of a switching power supply (quite annoying high pitched noise), which is approx. just as loud as (or even louder than) the fan. Is that normal? I dont really like this feature of the scope.
ksmith

Posts: 119
Registered: 08/06/09
Re: Noise problem on Agilent oscilloscopes
Posted: Feb 9, 2012 12:29 PM   in response to: Coris in response to: Coris
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"
Hi There!

I just bought a 2000 series MSO and what i am concerned about is its audible noise (not signal noise). I can hear the sound of a switching power supply (quite annoying high pitched noise), which is approx. just as loud as (or even louder than) the fan. Is that normal? I dont really like this feature of the scope.
"


That is definitely NOT normal, at least according to my ear. You SHOULD be able to hear 1 small click near the ned of it's boot cycle, and a very low level hum if you put your ear (my ear, anyway) up close to it. honestly, I can't even hear the fan unless I stick my ear up to it. How loud is your fan? I mean, can you hear it at arm's reach? if so, I woudl say that is not normal. I can well hear certain other instruments I have from quite a ways away... not the 2000x/3000x, though.

Anyway, I suggest you return your scope as an Outof Box Defect (OBD). It can be replaced or repaired. otoh, maybe you just have really good ears...

:)


:(

???
Baliszoft


Posts: 14
Registered: 02/09/12
Re: Noise problem on Agilent oscilloscopes
Posted: Feb 9, 2012 1:32 PM   in response to: Coris in response to: Coris
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Thanks for Your input!
Heres a fast video of the problem: http://youtu.be/jkhkd7OvubM
It is definitely louder than the fan, and can be heard at arms length.
It has something to do with the display, as when it goes blank the noise stops, too.
Got it online from rs-components, will give them a call tomorrow.
Coris

Posts: 86
Registered: 10/29/11
Re: Noise problem on Agilent oscilloscopes
Posted: Feb 9, 2012 2:53 PM   in response to: Coris in response to: Coris
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"
Thanks for Your input!
Heres a fast video of the problem: http://youtu.be/jkhkd7OvubM
It is definitely louder than the fan, and can be heard at arms length.
It has something to do with the display, as when it goes blank the noise stops, too.
Got it online from rs-components, will give them a call tomorrow.
"


I`ve seen your video. The noise of the fan is normal high as for this model. I just wander why Agilent do not use an low noise fan... It definitively not to be about an increase in the total high price of the scope in such case...
Else, about the another noise, I`m quite sure that it comes from the display, but not from main the PSU. I can hear the same "sound" from my own, but is very low. It seem to me that it is the high voltage converter for the backlight of the display which make that noise...
Definitively, not something to live with in the silence of a lab...
Baliszoft


Posts: 14
Registered: 02/09/12
Re: Noise problem on Agilent oscilloscopes
Posted: Feb 9, 2012 3:01 PM   in response to: Coris in response to: Coris
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"
I`ve seen your video. The noise of the fan is normal high as for this model. I just wander why Agilent do not use an low noise fan... It definitively not to be about a big increase in the total price for the scope in such case...
Else, about the another noise, I`m quite sure that it comes from the display, and not from the PSU. I can hear the same "sound" from my own, but is very low. It seem to me that is the high voltage converter for the backlight of the display which make that noise...
"


Thanks! I would be happy if i could hear the fan ONLY. The other sound is sadly louder and therefore more obvious :(. I am afraid they would not accept my claim at the dealer.
Coris

Posts: 86
Registered: 10/29/11
Re: Noise problem on Agilent oscilloscopes
Posted: Feb 9, 2012 3:04 PM   in response to: Coris in response to: Coris
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"
"
I`ve seen your video. The noise of the fan is normal high as for this model. I just wander why Agilent do not use an low noise fan... It definitively not to be about a big increase in the total price for the scope in such case...
Else, about the another noise, I`m quite sure that it comes from the display, and not from the PSU. I can hear the same "sound" from my own, but is very low. It seem to me that is the high voltage converter for the backlight of the display which make that noise...
"


Thanks! I would be happy if i could hear the fan ONLY. The other sound is sadly louder and therefore more obvious :(. I am afraid they would not accept my claim at the dealer.
"


Fully agree. You may try anyway... Maybe somebody from Agilent will "hear" you and may help you...
Baliszoft


Posts: 14
Registered: 02/09/12
Re: Noise problem on Agilent oscilloscopes
Posted: Feb 9, 2012 3:19 PM   in response to: Coris in response to: Coris
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"
Fully agree. You may try anyway... Maybe somebody from Agilent will "hear" you and may help you...
"


Maybe... Still wondering what do other people think about it.
I got two big LCD monitors on my desk (non LED), two PCs below the desk (with a total of 6 fans, 4 HD-s) and the MSO-X is louder than all this :).
Coris

Posts: 86
Registered: 10/29/11
Re: Noise problem on Agilent oscilloscopes
Posted: Feb 10, 2012 12:20 AM   in response to: Coris in response to: Coris
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"
"
Fully agree. You may try anyway... Maybe somebody from Agilent will "hear" you and may help you...
"


Maybe... Still wondering what do other people think about it.
I got two big LCD monitors on my desk (non LED), two PCs below the desk (with a total of 6 fans, 4 HD-s) and the MSO-X is louder than all this :).
"


Agilent state that every device is tested out before leave the production floor. I doubt seriously about this... Not only in your case, but in mine too... And it seems to be many such cases out there...
ksmith

Posts: 119
Registered: 08/06/09
Re: Noise problem on Agilent oscilloscopes
Posted: Feb 10, 2012 3:29 PM   in response to: Coris in response to: Coris
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"
"
I`ve seen your video. The noise of the fan is normal high as for this model. I just wander why Agilent do not use an low noise fan... It definitively not to be about a big increase in the total price for the scope in such case...
Else, about the another noise, I`m quite sure that it comes from the display, and not from the PSU. I can hear the same "sound" from my own, but is very low. It seem to me that is the high voltage converter for the backlight of the display which make that noise...
"


Thanks! I would be happy if i could hear the fan ONLY. The other sound is sadly louder and therefore more obvious :(. I am afraid they would not accept my claim at the dealer.
"


Hi Baliszoft (and anyone else with an audible noise problem on the scope),

honestly, your scope should be very very quiet, fan or otherwise. If it is not, it is an OBD. R&S should not have an issue taking it back... I re-iterate that I cannot hear mine unless I stick my ear right up to the fan... and even then it is a very low level "whir."

If there are ANY problems returning an OBD instrument to one Agilent's authorized distributors, please contact Agilent directly. If the score is within the warranty period, Agilent will repair it.
Baliszoft


Posts: 14
Registered: 02/09/12
Re: Noise problem on Agilent oscilloscopes
Posted: Feb 10, 2012 3:40 PM   in response to: Coris in response to: Coris
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I contacted RS today, though they told me i should write all my issues with the scope in an email to the customer service. I sent them the email, now i am waiting for their reply.
bret

Posts: 89
Registered: 07/05/11
Re: Noise problem on Agilent oscilloscopes
Posted: Feb 11, 2012 8:03 AM   in response to: Coris in response to: Coris
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Mine is absolutely quiet. Can't hear a thing unless I put my ear damn close to the fan, and like ksmith said, it's still barely audible. My PC's fan, harddisk (Caviar Black) and ionizer are the only noises I hear for my mini lab.

Dave Jones did a quick experiment to compare with the Rigol model, and it's about 10dB less noisy than the Rigol according to him http://www.youtube.com/watch?feature=pl ... q0#t=3205s
Baliszoft


Posts: 14
Registered: 02/09/12
Re: Noise problem on Agilent oscilloscopes
Posted: Feb 24, 2012 3:35 AM   in response to: Coris in response to: Coris
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Update: RS has replaced the noisy scope - took more than two weeks, but finally the new scope is quiet.
Coris

Posts: 86
Registered: 10/29/11
noise problem on Agilent oscilloscopes...
Posted: Apr 2, 2012 3:37 PM   in response to: Coris in response to: Coris
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I`ve reviewed again my last post (quite late...), and I could see that was a mistake with my conclusion about lowered noise level in the firmware v 2.10 There is nothing change in this field in this firmware version, as in the last one (2.12).
It was only my mistake to forget the BW option ON on my unit while making my last measurements, under the new at that time, firmware 2.10. That because I could see a lower noise level.
Sorry for presenting for a quite long time) some wrong informations in those my last two posts. I had to remove both the pictures and text, as non reflecting the facts...

I still have that opinion that it is recommended to proceed to an user calibration after installing a new firmware.

Edited by: Coris on May 12, 2012 10:31 AM
Coris

Posts: 86
Registered: 10/29/11
Re: Noise problem on Agilent oscilloscopes
Posted: Apr 8, 2012 4:34 AM   in response to: Coris in response to: Coris
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I`ve reviewed again my last post (quite late...), and I could see that was a mistake with my conclusion about lowered noise level in the firmware v 2.10 There is nothing change in this field in this firmware version, as in the last one (2.12).
It was only my mistake to forget the BW option ON on my unit while making my last measurements, after installing firmware 2.10. That because I could see a lower noise level.
Sorry for presenting for a quite long time) some wrong informations in those my last posts. I had to remove both the pictures and text, as non reflecting the facts...

I still have that opinion that it is recommended to proceed to an user calibration after installing a new firmware.

Edited by: Coris on May 12, 2012 10:31 AM
Coris

Posts: 86
Registered: 10/29/11
Re: Noise problem on Agilent oscilloscopes
Posted: Jun 11, 2012 2:40 PM   in response to: Coris in response to: Coris
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After the improvement process for my unit (shielding, serial PSU) were ended, I was not very satisfied with the solution I had at that time about ferrite bead for the flat cable connecting the keyboard and the main board. In the last time I found a more adequate (and small) ferrite bead for both the keyboard flat cable and the display flat cable. I placed two ferrite bead on both ends of the keyboard cable and one on one end of the display cable (see the pictures). The result is to be seen here. The EMI noises one can detect with a closed probe near to the display, it seems to come/radiate from those flat cables which goes back to the display. With a closed probe in this way (picture - a very good antenna) I can detect now a much lower noise when the probe is placed just on the display it self.

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