Author Topic: Looking for part: Through hole, straight entry, 50 ohm BNC for R&S repair  (Read 373 times)

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Offline DaJMasta

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Got a R&S SMJ100A that works great but was shipped underpacked, so it broke off one rear foot and significantly dented one of the rear panel BNCs.  Got out the old hammer and some wood and beat the back panel into flat enough shape, even got the threaded insert to reattach (though I will be epoxying to be sure), but the damaged BNC couldn't be straightened in my attempt and it's been very hard to find any suitable replacement.

The original is a Rosenberger part, 50 ohm, straight entry, through hole BNC with threads for a panel mount nut.  Body is 33.5mm, mounting pins are 4.5mm, body chunk is 15x15mm and 13.5mm tall (and is a solid chunk!)

While there are a number of replacements that look about right, the PCB entry points only seem to match some much shorter models... so I'm sort of running dry for a suitable replacement aside from just going with a panel mount model and soldering on some wires to jump it to the board.  The four ground pins/mounting pins are 1mm thick with a 12.7mm pitch in a square pattern, the center pin is a single 0.9mm conductor - most in this form factor seem to use two instead.


Any guess at where I could find one?  Can't find mention it on Rosenberger's site or an easy replacement from a major distributor or ebay new old stock listing.  Not critical to operation (low frequency baseband generator output), but I don't really want to reassemble the whole thing without it replaced.
 


Offline DaJMasta

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Re: Looking for part: Through hole, straight entry, 50 ohm BNC for R&S repair
« Reply #2 on: November 10, 2019, 08:14:25 pm »
A very different mounting style, I'm afraid, and I've really only been able to find that style available.  The mounting pin/spacing is 10.16mm.... which is not going to fit given I used calipers to measure the part I have, the pins are also too wide to fit in the holes on the PCB.  This is also the style that has a center signal pin and a second shield pin, which while not inherently a problem, isn't the style of the original.
 

Offline pbarton

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Re: Looking for part: Through hole, straight entry, 50 ohm BNC for R&S repair
« Reply #3 on: November 10, 2019, 09:06:10 pm »
 

Offline DaJMasta

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Re: Looking for part: Through hole, straight entry, 50 ohm BNC for R&S repair
« Reply #4 on: November 21, 2019, 04:30:13 am »
Much closer, but the part I was looking to replace is slightly larger in almost every dimension, and in the landing footprint.


Ended up just getting a panel mount BNC and using a header connector to connect it up to the original pad - since it's a low frequency output that goes through a ribbon cable already, it shouldn't negatively effect signal quality.  The BNC I ended up using was silver plated and actually fit through the hole entirely.... so I used a couple of washers to hold it in place - not the ideal fix, but it should do the job fine enough.
 


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