Found in a ham fest yesterday for $30. Absolutely no dust inside, must have lived in a clean room. What a find.

I made the same fan upgrade to my counter, added the 3Ghz and OCXO options. Very quiet now. But I do keep it on a switched outlet to not run the switched mode power supply ALL the time. I just turn it on in the morning if I need it that day for it to stabilize.

those telco connectors are clutch in an emergency

What a neat fan kit. It does a self test at power up.

In a such situation, I always check the fan or other item for proper operation before assembling it.

Nice repair! The unique mounting system probably contributes significantly to the noise reduction. Regards, David

Took my hp 53132a apart today . The fan wasn't that noisy but pulled the label off the fan and put some light oil on the bearing. Now can hardly hear it! Also sucked out all the fluff

Is the noctua going to have the same airflow / CFM as the delta?

I think it's interesting that Noctua's product design team looked at their grandparents' leather-trimmed tweed luggage from the 1950s and decided that was the way to go forward. 🤪 HP/Agiilent/Keysight's replacement for that counter series went with a 1" square OXCO unit that runs in Standby with the fan shut off. Oddly enough, the waveform generator in the newer series does NOT run its OXCO option in standby. Different LCD screens with contrast and backlight color temperature that don't match. Both these units and their older VFD counterparts seem like they were developed by different groups that didn't talk to each other much about details. This also reminded me of a place I used to work did assembly of a customer's product that had a fan with bolts going all the way through, although the fans specified were flange-only designs without support pillars or ribs. There was a whole box full of new fans with cracked and broken frames as a result. Some highly-payed engineers can be total ding-dongs sometimes...

Nice upgrade. You might be hearing the air going thru the small back plate slots.

The telephone company uses those yellow splices on outdoor telephone wires, which is why they're full of goo. There's a red 3-position version as well.

I think you'll find, those fan screws were posidrive, not phillips.

Great video

thats turn out to be a very nice noctua ad :)

One question that I am always asking me using Keysight Equipment - WHY IT IS SO LOUD????

Drop some IPA on the Silicon rubber , will slide no problem.

Buying a noctua fan you never have to worry if you got everything you need in there

I had to quiet down the obnoxious fan in my Instek spectrum analyzer. A 120 ohm 1 watt resistor in series with the 24V fan and small o-ring cushions between the fan and the metal chassis made a huge difference. Obviously CFM performance came down commensurate with voltage but my environment is far from worst case when it comes to cooling. I think these test equipment manufacturers choose cooling fans for the harshest of operating environments at the expense of some pretty obnoxious noise. It also helps to give these fan bearings a drop of oil.

I picked up a 9 digit HP 5334 counter on Ebay for $35. No need to pay $400 for a counter that you can't shut off!!

Are they pozidriv screws? How close are the cfm ratings of the two fans?

That seems like a great deal actually, as some of my HP kit is darn loud and could use this mod...cheers.

Great video! It would be really cool to see what else that a counter can do besides frequency.

At least it's not a high speed server fan 😁Screeching banshees.

Disappointed you didn’t measure the internal temp before and after, old fan and new fan. Hope the actual air flow is the same or better with the Noctua fan ? 👍🏻

Noctua fans are the best. I have them in various sizes haha

Fun

I wonder if you might be able to help - I have one of these and it won’t do any timing, only the frequency and period measurements work. If you were willing to probe a few lines on the FPGA for me it might help me troubleshoot mine… I’d be very grateful!

Agilent is saving money! If the fan is so important to thousands US$, couldn't they use a fan with tachometer output for few cents more?

Noctua might be expensive but all those extra goodies you get in the box makes them worth it, especially for quieting down old test equipment.

plus 1 for the “ugliest fan”. So true!

KZfaq put this video up for me after watching yours: kzfaq.info/get/bejne/gdOKqqSb0uCsqGw.html It is from Dave Jones at EEVblog where he buys an aftermarket TCXO from eBay for $70... Of course that was 8 years ago... He also complained about the fan noise. I thought you might like to see Dave installing, testing, and calibrating the oscillator to his rubidium standard.

$15 for a fan! Theres no id pay that. Just run the existing fan on a lower voltage. Does that PSU have a 5V rail.

Hiiii

Noctua fans are ugly