Agilent oscilloscope MSO-X 2012A audible high pitched sound and hiss - Page 1
Forum section: electronics / testgear

author: mark41
author_rank: Contributor
timestamp: February 04, 2016, 09:03:39 pm
content: Hi folks!I've got a problem with my scope which is really pissing me off! I only found one comment about that problem at keysight's forum but that was solved by giving a new unit to the costumer. I have no waranty with my scope. So...The high pitched sound is audible since the start of the unit - to be precise - it's connected with display LED backlight (when I disconnect the backlight, it's volume is almost impossible to hear). The sound is increasing in volume and reaches stable maximum after about 5min. Unfortunatelly it's not audible on the video I took. I also found something strange. When I touch the caps above the coils with a probe (that isn't connected anywhere) it starts doing funny hissy noises like tuning a radio (adding capacitance?) and also when I touch hard with my finger the top enge of the pcb and the middle coil with my thumb (showed in the video) the high pitched sound stops completely! Any suggestions/help? It really drives me crazy. Thank you!Video - in first 5sec you can how camera's focusing sound is like, unfortunatelly the high pitched sound that I talk about is not hearable...which is there from the beginning of the video

author: trevwhite
author_rank: Frequent Contributor
timestamp: February 04, 2016, 09:08:08 pm
content: I would contact Keysight as their customer support is really good. Even if it is out of warranty you never know, they might sort something out.

author: Pinkus
author_rank: Frequent Contributor
timestamp: February 04, 2016, 10:55:59 pm
content: I do not know if your hissing is caused by the same problem. But you may give it a try:Read this:http://cp.literature.agilent.com/litweb/pdf/DSOX3014A-03.pdf

author: mark41
author_rank: Contributor
timestamp: February 04, 2016, 11:06:22 pm
content: Thank you!!I will look into it deeply tommorow.

author: mark41
author_rank: Contributor
timestamp: February 05, 2016, 10:54:32 am
content: Unfortunatelly, the pcb layout really differs, so there's no use. However I was digging in the internet the whole morning and tried putting my model and SN to Keysight webpages and voilà service note for my scope! And it suits to my video as well.I am going to order that inductor and hopefully I'll be lucky next week.

author: fanOfeeDIY
author_rank: Unknown
timestamp: February 05, 2016, 03:48:17 pm
content: Typically the hissy high pitch noise from inductors are caused when the current flow the inductors and vibration frequency becomes in the hearing range.It is not recommended solution, but often time, it could be solved by gunk the inductors with hot glue gun or some elastic material.Then the vibration frequency goes out of the hearing range.

author: Keysight DanielBogdanoff
author_rank: Unknown
timestamp: February 05, 2016, 07:24:36 pm
content: I fully expect that replacing the inductor will fix it.

author: HighVoltage
author_rank: Super Contributor
timestamp: February 06, 2016, 09:24:03 am
content: Thanks for the link to the Service Note...I did not know that the service guide is available for these 2000X and 3000X scopeshttp://cp.literature.agilent.com/litweb/pdf/75019-97039.pdfJust too bad there is no schematics inside.

author: Pinkus
author_rank: Frequent Contributor
timestamp: February 06, 2016, 01:35:30 pm
content: it is also available as a Keysight branded version:http://www.keysight.com/main/redirector.jspx?action=ref&cname=EDITORIAL&ckey=2032052&lc=ger&cc=DE&nfr=-32542.1150190.00I am just mention it, as it is a newer version. But beware: as the Keysight version has less pages, the Agilent branded version might show additional information (I did not check for any difference; I am keeping both versions on my hard drive in case I ever need it).

author: Hydrawerk
author_rank: Super Contributor
timestamp: April 25, 2016, 08:17:05 pm
content: Quote from: Keysight_DanielBogdanoff on February 05, 2016, 07:24:36 pmI have the same problem with my scope, but the hiss sound is rather quiet. Can this develop into a major failure of the inductor? Is it necessary to replace it when I do not care about the weak hiss sound?BTW I mentioned this little problem in March 2015.https://www.eevblog.com/forum/reviews/my-new-toy-)-agilent-dsox2002a-sex-on-a-stick!/msg619692/#msg619692

author: mark41
author_rank: Contributor
timestamp: April 25, 2016, 08:24:43 pm
content: Sorry that I havent replied for a long time. I ve been busy with university studies. YES, when I changed the inductors and removed the resistors the hiss is now completely gone...

author: Keysight DanielBogdanoff
author_rank: Unknown
timestamp: April 26, 2016, 05:49:21 pm
content: Quote from: mark41 on April 25, 2016, 08:24:43 pmAwesome! Thanks for following up!

author: kawal
author_rank: Frequent Contributor
timestamp: February 18, 2020, 02:59:34 pm
content: Can anyone provide the specs for the 68uH inductors (9140-6151 (68 uH)) ? What footprint / frequency / amperage is needed. Thank youMaybe someone has a non HP part number.I was thinking one of these would be OKSRR1050A-680Y which is a 10mmX10mmx5mm part rated for 1.6A710-784771680 which is a 12mmx12mmx6mm part rated for 1.8AThanks

author: rernexy
author_rank: Contributor
timestamp: January 08, 2021, 11:22:44 am
content: 8 years after the service note was released, I've done the change to my MSOX3054A. It certainly solves the hissI did a terrible job removing the 1R0 resistors, as the photo shows. After removing as much of the solder as I could, I used side cutters to violenty cut-crush them off. I'd had enough at that pointThe inductors I used were these by Coilcraft:MSS1038T-683MLBhttps://www.coilcraft.com/en-us/products/power/shielded-inductors/ferrite-drum/mss-mos/mss1038t/mss1038t-683/