LeCroy 9354AL noisy fan replacement - Page 1
Forum section: electronics / testgear

author: davorin
author_rank: Unknown
timestamp: June 30, 2014, 12:07:10 pm
content: Someone has an idea how much air the fan of a LeCroy 9354AL blows out per minute?I'm currently replacing all fans of my lab equipment and the one from the DSO is definitively the loudest one...though I assume it blows also the most air per minute...

author: Stray Electron
author_rank: Super Contributor
timestamp: June 30, 2014, 01:51:29 pm
content: There's a post on the internet somewhere that gives the info that you're looking for. I have it book marked on my other computer, I'll dig it up and link to it from there later. BUT IIIRC the original fan is about 80 cfm. But you need to be aware that it's powered through a voltage dropping resistor (surface mount) so you have to be careful about how much current your replacement fan draws or you will burn out the resistor. The original was 26 ma IIRC. The link tells of a cheap (relatively) computer fan that you can get from E-bay and meets meets all of the requirements. My fan is still good but I'm looking for a variable speed fan that I can replace it with.

author: grumpydoc
author_rank: Super Contributor
timestamp: June 30, 2014, 03:16:39 pm
content: QuoteProbably my posts on the Yahoo Lecroy forumYou want an Aerocool Sharkhttp://www.aerocool.us/accessory/shark_b12.htmlThey are rated at 82.6CFM or 140.3m3/hr pretty much spot on with the original Papst 4312m, power is 3.6W at a nominal 12V and static air pressure similar to the Papst. However SPL is almost 13dB better.If you choose some other fan watch out for the fact that the fan supply is fed from the 15V rail via a 1W 6.2ohm resistor so you are a bit limited on max current draw before that's going to get too hot.You need to swap the 0V/+12V lines on the fan connector, then it will go onto the motherboard header pins.

author: Stray Electron
author_rank: Super Contributor
timestamp: June 30, 2014, 08:02:57 pm
content: Quote from: grumpydoc on June 30, 2014, 03:16:39 pmYeap, it was your post but actually it was here on EEVBlog! Here's the linkhttps://www.eevblog.com/forum/chat/just-won-old-lecroy-9374l-4ch-1ghz-2gss-max/OP if you're not in the Lecroy forum, you should join. There's lots of good information there.

author: davorin
author_rank: Unknown
timestamp: July 11, 2014, 12:12:51 pm
content: Hmm...looks like this one here available in Switzerland...quite cheap though compared to industrial fans like Micronel...https://www.digitec.ch/ProdukteDetails2.aspx?Reiter=Details&Artikel=295494

author: davorin
author_rank: Unknown
timestamp: August 30, 2014, 10:26:28 am
content: Okay...got the fan now from Aerocool....But as I just re-read the forum psots here...the original Papst fan has a pwoer rating of 0.36W, whereas the Aerocool has a power rating of ten times that...3.6W!My one of the many 6632Bs tells me 0.265A@12V..

author: davorin
author_rank: Unknown
timestamp: August 30, 2014, 06:44:46 pm
content: I thought I do some temperature measurements with before/after values....so I placed inside my 9354AL a Raspberry Pi with WLAN stick and attached DHT temperature sensor....The original Papst fan is running at around 13.3V....so fed fan voltages from outside with a 6632B to also be able to control it....and of course also to let the 9354AL cool it down faster when it is powered off...From first impression the Aerocool Shark fan blows much less air than the original Papst....so no clue where the close volume figures are coming from..at least Aerocool is cheating here...And when comparing the temperature rises when running the 9354AL for half an hour...the Aerocool Shark fan is less capable of cooling it down...resulting in a temperature increase of 4 degrees Celsius within short time...And as a side note...I did run the Aerocool shark here with a voltage of 15V !!! So with around 13.3V as the Papst fan, the temperature rise is even higher...From my point of view...this Aerocool Shark fan is an absolutely no go!!!

author: davorin
author_rank: Unknown
timestamp: August 30, 2014, 07:13:03 pm
content: Here's my Raspberry Pi temperature sensor inside the 9354AL....not brilliantly accurate, but for measuring differences it's enough...

author: grumpydoc
author_rank: Super Contributor
timestamp: September 01, 2014, 07:53:20 pm
content: Quote from: davorinThe Papst has a rating of 3.1W, the Aerocool 3.6W - the 0.36W was a typo (which I've now corrected).Seehttp://img.ebmpapst.com/products/datasheets/DC-axial-fan-4312M-ENG.pdfQuote from: davorinSorry to hear that - and actual temperature measurements are always helpful, that's some very useful data.While I haven't made measurements I didn't have the impression that the air flows was any less with the Aerocool. It is, however, possible that the Papst's in the two 'scopes when I got them were not performing as they should - there was quite a lot of sticky gunk attached to both fans.

author: davorin
author_rank: Unknown
timestamp: September 01, 2014, 08:03:53 pm
content: Well I just saw recently that Farnell is still selling those Papst fans with the same model number...Tomorrow I get some 4 new fans to test with and acquire some new temperature profiles...keep you posted with some nice graphs (o;I just want to be on the save side to not blow up some precious "unobtainium" inside my beloved 9354AL (o;Haven't found some 9374AL so far for good value...

author: grumpydoc
author_rank: Super Contributor
timestamp: September 01, 2014, 09:00:54 pm
content: Quote from: davorinOne thing I would say is that if you do find a 9374 or 9384 then the Aerocool fan probably wouldn't be a good idea - they have a different Papst fan. I can't find my note of which but I think it was the 4312Twhich has a flow of 170m³/h.

author: davorin
author_rank: Unknown
timestamp: September 01, 2014, 09:05:56 pm
content: I was already thinking of punching a hole in the wall to fit in the equipment...so it will blow in the next door room (o;Wonder how much is a 9374/9384 these days anyway...

author: Stray Electron
author_rank: Super Contributor
timestamp: September 03, 2014, 02:04:37 am
content: "Wonder how much is a 9374/9384 these days anyway..."FWIW I paid $40 for the 9370M that I just picked up. Case was smashed all to pieces. One knob on the front is split and a piece is missing but it isn't loose and it still works. The 50 Ohm shunt in Chan 2 is out. Other than that it's working fine. It has CPU3, PCMCIA card reader, RS-232, GPIB and parallel port.

author: marshallh
author_rank: Unknown
timestamp: September 03, 2014, 05:08:13 am
content: Paid $450 for my 9374C. Probably put about another $500 into it between probes, replacement parts 2gs bridge and unlocked GAL.

author: Wuerstchenhund
author_rank: Super Contributor
timestamp: September 03, 2014, 05:24:37 am
content: Quote from: davorin on September 01, 2014, 09:05:56 pmThey seem to be still pretty expensive unless you're lucky or buy one that's broken. For the same (or probably even less) money you might get a LC Series scope which not only gives you color screen but also much faster processing.

author: davorin
author_rank: Unknown
timestamp: September 05, 2014, 04:39:45 pm
content: Finally found some time to test some more PC fans....1. Enermax T.B. Silence PWM 121m3/h 18dB2. Noiseblocker NB-BlackSilentFan XL-P 128m3/h 16dB3. Scythe Slip Stream 120 PWM 126m3/h 26.5dB4. Noiseblocker NB-eLoop B12-3 121.20m3/h 26.5dBWith fan number 1 and 3 I let run the 9354AL until it reached around 35 degrees Celsius, as the temperature rise was still not flattening out...so didn't wanted to risk some unobtanium losses here (o;What surprised me was the fact that the Noiseblocker fans with lower CFM/m3/h as the Aerocool Shark cooled the 9354AL much better...So nbr. 2 and 4. are the winners here....the Noiseblocker B12-4 is currently not on stock...but maybe also worth a try as it should have 160m3/h.What I also discovered....the Noiseblocker fans made the least noise of all models...although one of them is specified at 26.5dB...Guess those figures are measured free air....and the actual noise depends heavily where it is fitted in the end (turbulences caused inside of case maybe?).BTW: All fans where powered with a constant 15V supply from a 6632B...I will let run now a longer test with internal fan supply..also with comparison with original fan...and I definitively need to buy a cheap handheld sonic meter (o;

author: davorin
author_rank: Unknown
timestamp: September 06, 2014, 09:49:00 am
content: Hmm...is the PCMCIA memory card slot needed at the back or can it be removed without impact on the functionality?Just thinking of maybe fit in a fan with 140mm x 140mm dimension....

author: davorin
author_rank: Unknown
timestamp: September 06, 2014, 04:04:08 pm
content: Just came back with some new fans to test (o;First one mounted was the Cooler Master Jetflo 120 Blue LED PWM....An impressive 161.41 m3/h.....But...this fan though with higher airflow and a little less noise than the original Papst fan....it is even worse then the Noiseblocker with much lower airflow tested before...Next came the AeroCool Shark Fan Devil Red Edition LED...though 140mm x 140mm dimension...it can be made fit inside when you wide the holes of the PCMCIA holder some 2mm to the left to make some more room for it...this one claims to have 163.95 m3/h....but as it turned out...this one is bad as heel ...Shut off the tast after reaching 35 degrees shortly...

author: davorin
author_rank: Unknown
timestamp: September 07, 2014, 04:20:23 pm
content: Have now mounted the Noiseblocker NB-BlackSilentFan XL-P inside the 9354AL....though probably it could be a little better by removing the 6R2 resistor to gain some airflow...the figure is not bad....I let run the machine for over an hour and the temperature flattened out around 33 degres Celsius with two channels switched on...Still to come tests with:Noiseblocker NB-eLoop B12-4, 150.30 m3/h, 34.29 dBNoiseblocker NB-eLoop B12-P, 132.40 m3/h, 28.40 dBNoiseblocker Multiframe MF12-P, 133 m3/h, 29.30 dBSo far overall summary:I'm impressed by the Noiseblocker fans...though lower claimed airflow they perform much better than any other with 150 - 160m*/hYou can't trust any specification from a fan manufacturer at all, not airflow, not noise, you have to find out for yourself which one is best for your application

author: Stray Electron
author_rank: Super Contributor
timestamp: September 07, 2014, 04:48:04 pm
content: Good information! Keep it coming! I'm not a bit surprised that the manufacturer's specs are more wishful thinking than anything else. It would be nice to find a fan that would run directly from 15VDC and then you could eliminate the dropping resistor completely.

author: davorin
author_rank: Unknown
timestamp: September 07, 2014, 06:25:15 pm
content: Do you know how to get to the resistor?What is still missing some sonic measurements....I intended to hook up a microphone to my 9414...but it just died this weekend...dead power supply...Not sure if I can trust those cheap Chinese sonic meters...Or is there some known Linux/Windows software which can be used for sonic measurements together with a USB microphone for example?