Need help looking for Type-N connector with weird dimensions - Page 1
Forum section: electronics / projects

author: nexus
author_rank: Regular Contributor
timestamp: February 15, 2022, 05:36:46 am
content: Hi all,I am tearing down an Agilent N1911A power meter that I got relatively cheap on fleabay. It must have been a rental unit because this thing has seen some action. The front panel Type N connector which provides a 50Mhz, 0dBm reference signal has all the plating worn off and some dings on the threads. I'd like to replace it, which would be easy if I could find another one like it!In the pics attached, you can see some of the dimensions. It is a Type-N female connector with a 4 hole flange. The flange is 12.7mm (0.500 inches) square, with 8.636mm (0.340 inch) hole spacing. I have been able to find a few Type-N connectors with these dimensions, such as pasternack PE4355 or Huber+Suhner 23_N-50-0-16133_NE.The challenging dimension seems to be the length. The distance from the face of the Type-N connector to the bottom flange face is 26.7mm (1.05 inches). Apparently nobody, and I mean nobody (Amphenol, TE connectivity, Cinch, Pasternack, Rosenberger, Anoison, Fairview microwave, Southwest microwave) makes a connector with these dimensions.Of course, it also does not exist in the Keysight online parts store. They have the E4418-20009 avaialble for purchase, but this is a Type-N female to SMA female bulkhead mount connector for N1911A/N1912A with the rear panel output option (opt. 003).https://www.keysight.com/my/partDetail/E4418-20009Short of making a new connector, I need some help if anyone knows where to find odball coax connectors like this.Thanks

author: bob91343
author_rank: Super Contributor
timestamp: February 15, 2022, 06:41:50 am
content: Can't you hoke up a setup that would work? Or modify an existing connector.

author: nexus
author_rank: Regular Contributor
timestamp: February 15, 2022, 06:45:14 pm
content: Quote from: bob91343 on February 15, 2022, 06:41:50 amI could always jerry rig something if I was in a pinch. But I'm not in a rush to use this meter and I want to fix it properly, as it would have been originally.I managed to press out the center conductor and insulator without damaging anything. Perhaps I might be able to have the metal body replated, since it is proving impossible to find an off the shelf replacement.Worst case, if I cant salvage the original connector, I'll end up having to buy a similar one and have it machined. The challenge there is how to preserve the finish while also turning the connector into two pieces, adding metal, and fusing all the parts together...

author: Neomys Sapiens
author_rank: Super Contributor
timestamp: February 16, 2022, 03:01:49 am
content: Do you know where this power meter is/was produced? (Plant/country)

author: nexus
author_rank: Regular Contributor
timestamp: February 16, 2022, 04:45:21 am
content: [ Specified attachment is not available ]Quote from: Neomys Sapiens on February 16, 2022, 03:01:49 amThe serial # tag says it is made in Malaysia, so I'm guessing its made in the main Keysight Malaysia plant that does most of their high volume instruments.The calibrator board is also individually labelled with part # "N1911-60004" and "Made in Malaysia".I managed to clean the connector up better than expected. I was soaking all of the screws in POR-15 rust remover and figured "why not throw this in there too?". I think it got rid of a lot of oxidation and surface corrosion, so that was a pleasant surprise.

author: nexus
author_rank: Regular Contributor
timestamp: February 17, 2022, 04:47:58 pm
content: More news on this adventure.After cleaning this connector up in POR-15, I decided to try and polish it up with some green scotchbrite. I think it did a great job of removing the tarnish and light scratches.The connector did turn a little yellow. This happened when I put some light cutting oil on the scotchbrite to possible improve the polish by creating an abrasive suspension. I will attempt to replate it since I'm sure the original plating is getting thin. I believe the original finish is semi-bright nickel.After doing a ton of research, it looks like electroless nickel is the way to go. More uniform finish, especially is nooks and crannies (like threads). This is turning into its own tangential science project!Also have a similar Agilent power meter in the office. Took a picture of the calibrator connector on that for reference as to what the original finish should look like. Appears to be semi satin nickel again, with a light brushed appearance.More to come once the plating goodies arrive.

author: nexus
author_rank: Regular Contributor
timestamp: March 10, 2022, 04:18:13 am
content: Ok, down the rabbit hole we go....After doing lots of research, looks like electroless nickel plating is the way to go for parts with small features like threads, etc. Did a bunch of research and ended up buying an electroless nickel kit from Caswell.Also found myself a fancy digital hotplate/stirrer, and got some glassware. After polishing the connector with red jeweler's rouge to a mirror finish, did a hot degreaser, 10% HCL acid dip to activate the metal, then into the plating solution at 195F for one hour.I think it came out pretty good, especially considering that this is the first time I've ever done any kind of metal plating. Reassembling and testing confirms that the meter is working as intended, including the reference output!Needs a little calibration because the power sensor is actually reading high (0.21 dBm instead of 0.00 dBm).Probably because the connector finish was so bad before that there was some loss at that interface that was calibrated out previously.

author: dave_k
author_rank: Frequent Contributor
timestamp: March 11, 2022, 10:56:38 am
content: That's a mighty fine result. Well done!