Author Topic: Agilent 34410A Noisy fan  (Read 10430 times)

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Offline jstarrTopic starter

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Agilent 34410A Noisy fan
« on: July 12, 2014, 02:38:32 pm »
I just bought this from Ebay and it works beautifully but the fan is noisy and the speed (by its sound) appear somewhat irregular.  Oddly, if I put one of my fingers partly over the intake (about 1/4 of the intake) the fan speed and sound becomes quiet and regular.  Any suggestions or should this be my first Tear Down !!

john
 

Offline engineer_in_shorts

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Re: Agilent 34410A Noisy fan
« Reply #1 on: July 12, 2014, 10:29:22 pm »
Bearings?
 

Offline LA7SJA

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Re: Agilent 34410A Noisy fan
« Reply #2 on: July 26, 2014, 07:00:52 am »
The 34410-68502 (replaced bye 34410-68503) Assembly-Fan should be replaced.

http://www.home.agilent.com/myagilent/faces/partDetail.jspx?partNumber=34410-68503&imageStatus=YES

JFG
« Last Edit: July 26, 2014, 07:41:06 am by LA7SJA »
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Offline HighVoltage

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Re: Agilent 34410A Noisy fan
« Reply #3 on: July 26, 2014, 08:46:02 am »
I have installed low noise Papst fans in almost all my instruments that made too much noise.
Papst makes them with internal thermistors on a little cable and you can place this sensor on the most heated part of the
instrument (heatsink) and the airflow will increase when needed. I have been doing this for years and never had any heat
problems with any Agilent instruments


 
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Offline engineer_in_shorts

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Re: Agilent 34410A Noisy fan
« Reply #4 on: July 26, 2014, 09:23:34 am »
I have installed low noise Papst fans in almost all my instruments that made too much noise.
Papst makes them with internal thermistors on a little cable and you can place this sensor on the most heated part of the
instrument (heatsink) and the airflow will increase when needed. I have been doing this for years and never had any heat
problems with any Agilent instruments

Hi,
I am interested in these.  Do you have some part numbers or links to these products?
 

Offline HighVoltage

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Re: Agilent 34410A Noisy fan
« Reply #5 on: July 27, 2014, 12:21:03 pm »
Hi,
I am interested in these.  Do you have some part numbers or links to these products?

Sure.
I just bought a broken Agilent E3640A PSU and it has a noisy fan too.
When I replace it, I will take some pictures and write down the part numbers of the fan I will be using.

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Offline engineer_in_shorts

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Re: Agilent 34410A Noisy fan
« Reply #6 on: July 27, 2014, 01:37:00 pm »
 

Offline rob77

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Re: Agilent 34410A Noisy fan
« Reply #7 on: July 27, 2014, 03:02:49 pm »
the best way is to replace the fan, but while your replacement arrives , you can "fix" the old one.
remove the fan from the equipment, disassemble the fan to the level needed to uncover the bearing (cheaper fans got only a sticker protecting the bearing) and add few drops of silicone oil to the bearing. it will become quite after this for few weeks/months - depends on the run-time.
 

Offline SeanB

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Re: Agilent 34410A Noisy fan
« Reply #8 on: July 27, 2014, 03:06:51 pm »
Not silicone oil, but a drop of plain car engine oil works well. 0W15 synthetic oil works the best.
 

Offline HighVoltage

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Re: Agilent 34410A Noisy fan
« Reply #9 on: July 27, 2014, 03:14:52 pm »
Not silicone oil, but a drop of plain car engine oil works well. 0W15 synthetic oil works the best.

Interesting, that you tested this.
I also have used high quality silicone oil for this kind of work but I never tried automotive synthetic oil.

The fan noise not only comes from the bearings but also from the airflow and geometry and of course the speed.
Getting a speed regulated fan makes all the difference in the world.

I had the same on a LeCroy oscilloscope.
That fan was so noisy, it was kind of torture, sitting next to it.
LeCroy advised against the changing of the fan and I did it anyways and it worked out perfectly.
Now the LeCory scope is as quiet as my new Agilent scope.



 
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Offline HighVoltage

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Re: Agilent 34410A Noisy fan
« Reply #10 on: July 27, 2014, 03:26:48 pm »
i think i have found it,  page 14 on this PDF:
http://www.ebmpapst.us/media/content/products/downloads/DC_fans_specials_2011.pdf

I just looked through my boxes and found the right one for the Agilent E3640A PSU
It is the PAPST Type 612MI
This one is 25,3 mm thick and 60 x 60 mm outside dimensions

See enclosed pictures. Right next to the cable is the Thermistor for this fan.
I have installed this PAPST type fan in several Agilent PSU and never had a problem with them.
 
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Offline rob77

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Re: Agilent 34410A Noisy fan
« Reply #11 on: July 27, 2014, 03:29:57 pm »
just one note regarding the oil... i'm sure the engine oil (virtually any lubricant) will work. but i'm using silicone oil because of it's properties:
1. non corrosive
2. clean , transparent and odorless
3. it's a fairly good lubricant
4. it's not conductive
 

Offline SeanB

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Re: Agilent 34410A Noisy fan
« Reply #12 on: July 27, 2014, 04:05:26 pm »
I have done a fair number of fans where you could not replace them easily ( cost, availability and lead times) and the drop of oil worked for a long period, often months or years. Silicone oil is not the best lubricant in a bearing, as it tends to polymerise with time and with temperature, turning into an abrasive. As well the breakdown product is silicon dioxide, AKA sand. Mixed with carbon based oil and you get as a breakdown product silicon carbide, or grinding paste.

The engine oil is light enough to lubricate, but thick enough that it will stay put in the bearing, providing a nice hydrodynamic film to reduce the friction between the sleeve and the shaft. It likely is also the original oil as well. Oilite bushes are typically prepared during manufacture after sintering by dumping them hot into hot oil which both cools them and impregnates them with oil. A lot these days seem to be made from leaded steel powder pressed into a bush then sintered, must be cheaper than bronze or brass powder.
 

Offline rob77

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Re: Agilent 34410A Noisy fan
« Reply #13 on: July 27, 2014, 05:03:06 pm »
agree with all you wrote... but think of the plastic sleeves and the engine oil ;) silicone oil is used for lubrication of small parts (low temperature, low stress) surrounded by plastics for a good reason ;)
the engine oil is designed to lubricate metal parts in a high temperature environment, it might easily contain additives which are aggressive to the "low quality" plastic used in electronics.
and last but not least - who has some engine oil handy in his lab ? if someone is doing machining along with electronics, then he might have some cutting oil or even engine oil handy.. but otherwise... ;)
 

Offline SeanB

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Re: Agilent 34410A Noisy fan
« Reply #14 on: July 27, 2014, 05:24:43 pm »
Engine oil is quite common as a lubricant, used for bushes on open switches in older equipment. There you just need a drop, so I use a 5ml syringe to keep it around. I also keep some synthetic grease around for the same reason. It makes a very nice reconstitutor for dried up thermal paste if you just are taking a part off and putting it back.
 

Offline David Hess

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Re: Agilent 34410A Noisy fan
« Reply #15 on: July 28, 2014, 03:17:36 am »
I try to avoid silicon oil because it tends to creep.

For fans bearing my current favorite oil is heavy gear oil like you would use in a transmission or differential.  Over the past couple years, the worn fan bearings I have used it on have more than doubled their operating life without incident and are still going.

Quote
and last but not least - who has some engine oil handy in his lab ? if someone is doing machining along with electronics, then he might have some cutting oil or even engine oil handy.. but otherwise...

I keep a couple of small clearly labeled plastic dispensing bottles with needle tips for things like contact cleaner and lubricant (MG Chemicals 801B), gear oil, light machine oil (LPS 2 or similar), flux (Kester 1544), Copper Nu, etc.
 

Offline SeanB

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Re: Agilent 34410A Noisy fan
« Reply #16 on: July 28, 2014, 04:50:23 am »
Lubricants I keep at work are vacuum pump oil, 3 different refrigerant oils, 2 different compressor oils, 2 different gearbox oils and then greases, one synthetic food grade and 2 different greases. A small amount of moly grease as well along with tacky wheel bearing grease for odd uses. They are pretty useful, though I do tend to buy them in 20l drums.
 

Offline Odd

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Re: Agilent 34410A Noisy fan
« Reply #17 on: April 16, 2023, 05:16:47 am »
Fan in a multimeter?  ( 34410A )  - that's a first ... what's the crazy reason for such requirement?
also: can anyone suggest a suitable, silent, replacement specifications?
 

Offline HighVoltage

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Re: Agilent 34410A Noisy fan
« Reply #18 on: April 16, 2023, 10:12:34 am »
Just install a Papst SUNON fan of the same size and add a 100 Ohm series resistor in the supply cable to slow the fan down a little. I have done this on every 34410A that I have / had.

« Last Edit: April 17, 2023, 10:19:34 am by HighVoltage »
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Offline Odd

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Re: Agilent 34410A Noisy fan
« Reply #19 on: April 16, 2023, 06:23:23 pm »
can you please tell me the papst fan model you have used for 34410A ? (I'd like to avoid disassembly just to figure out the dimensions and voltage & wattage/current)   
 

Online RolandK

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Re: Agilent 34410A Noisy fan
« Reply #20 on: April 16, 2023, 08:20:34 pm »
The 34410A / 34411A seem to have 30 / 10 mm fans.
The 34465A / 34470a seem to have 40 / 10 mm fans. Both just measured on the backside.
The E3449a seems to have 80 / ? mm fans.
In the https://www.ebmpapst.com/content/dam/ebm-papst/media/catalogs/products/Catalog_Compactfans_US_en.pdf is only a 40 / 10 mm fan, no 30 /10. So no luck with this. :(
Why do old schaffner filters blow? - because there are rifas inside.
Why do rifas blow? Only time shows if the best new thing is really best. Here it is not.
 

Offline HighVoltage

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Re: Agilent 34410A Noisy fan
« Reply #21 on: April 17, 2023, 10:17:47 am »
can you please tell me the papst fan model you have used for 34410A ? (I'd like to avoid disassembly just to figure out the dimensions and voltage & wattage/current)
It has been too long since I did this mod.
I just looked at my notes, this was not a Papst fan.
I used Papst fans for other Agilent gear.

The fan you need for the 34410A and 34411A is a 12V 35x35x10mm.

The model that I installed was a:
Sunon MF35101V1-1000U-A99 Axial fan 12 V DC 12.24 m³/h (L x W x H) 35 x 35 x 10 mm
« Last Edit: April 17, 2023, 10:20:02 am by HighVoltage »
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Online RolandK

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Re: Agilent 34410A Noisy fan
« Reply #22 on: April 23, 2023, 07:34:09 pm »
In my 34411a with serial number starting MY48 is a 1204KL-04W-B40 12V DC 0.1A from NMB-MAT (Minebea-Matsushita) which is 30x30x10mm.

Did they change the size, e.g. in later versions? Or did you modify the fan-mounting with a drill and dremel? :-BROKE
Why do old schaffner filters blow? - because there are rifas inside.
Why do rifas blow? Only time shows if the best new thing is really best. Here it is not.
 

Offline HighVoltage

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Re: Agilent 34410A Noisy fan
« Reply #23 on: April 23, 2023, 09:19:42 pm »
Nothing was changed, definitely not with a dremel.  :-DD

I am traveling right now. When I am back, I will open one instrument and take some pictures.
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Online RolandK

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Re: Agilent 34410A Noisy fan
« Reply #24 on: April 25, 2023, 01:51:45 pm »
You had the same fan, here are your pictures: https://www.eevblog.com/forum/repair/agilent-34410a-repair-attempt-of-2-dead-meters/msg820491/#msg820491

i ordered now sunon HA30101V3-1000U-A99
Why do old schaffner filters blow? - because there are rifas inside.
Why do rifas blow? Only time shows if the best new thing is really best. Here it is not.
 


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