Forums

Problems we don't need

Started by Sylvia Else November 10, 2021
Bought a couple of oscilloscope probes today to replace those damaged/lost.

They don't fit, because the plastic surround exceeds the specified 
diameter for a BNC plug. My scope has a hole in its front plate to 
accommodate a standard BNC plug, but it's not big enough for this 
oversized plastic variant.

This probably saves several cents per probe, but created a problem I 
didn't need.

Sylvia.
Sylvia Else <sylvia@email.invalid> wrote in
news:iv3i4nFarmlU1@mid.individual.net: 

> Bought a couple of oscilloscope probes today to replace those > damaged/lost. > > They don't fit, because the plastic surround exceeds the specified > diameter for a BNC plug. My scope has a hole in its front plate to > accommodate a standard BNC plug, but it's not big enough for this > oversized plastic variant. > > This probably saves several cents per probe, but created a problem > I didn't need. > > Sylvia. >
Dremel is your friend.
On Thu, 11 Nov 2021 14:48:38 +1100, Sylvia Else <sylvia@email.invalid>
wrote:

>Bought a couple of oscilloscope probes today to replace those damaged/lost. > >They don't fit, because the plastic surround exceeds the specified >diameter for a BNC plug. My scope has a hole in its front plate to >accommodate a standard BNC plug, but it's not big enough for this >oversized plastic variant. > >This probably saves several cents per probe, but created a problem I >didn't need. > >Sylvia.
I had a similar problem with some long forgotten piece of SCADA hardware. The BNC plugs fit, but they were so close together that even the official insertion/removal tool didn't fit. However, this was using a 50 ohm system, not the much higher impedance of a scope probe. I created an adapter of sorts to elevate every other connector. It was a UG-88C/U plug with BNC panel mount receptacle crammed into the plug. A short piece of bare wire connected the center pins and an ugly solder blob connected the grounds: <https://www.newark.com/amphenol-rf/ug-88c-u/rf-coaxial-bnc-plug-50-ohm-cable/dp/04M6671> <https://www.newark.com/amphenol-rf/31-10/connector-bnc-bhd-jack-str-50/dp/38F1322?st=bnc%20panel> The resulting adapter added about 1 inch to the length of the 50 ohm connection. Whether the added capacitance will cause problems on your oscilloscope will need to be determined. If you want to just see if such an adapter has a chance of working, try connecting a BNC M-M adapter (UG-491A/U) to a BNC F-F adapter (UG-914/U). This will extend the line length by 1.75 inches. If it works, build a shorter adaptor. -- Jeff Liebermann jeffl@cruzio.com PO Box 272 http://www.LearnByDestroying.com Ben Lomond CA 95005-0272 Skype: JeffLiebermann AE6KS 831-336-2558
On 12-Nov-21 1:01 pm, Jeff Liebermann wrote:
> On Thu, 11 Nov 2021 14:48:38 +1100, Sylvia Else <sylvia@email.invalid> > wrote: > >> Bought a couple of oscilloscope probes today to replace those damaged/lost. >> >> They don't fit, because the plastic surround exceeds the specified >> diameter for a BNC plug. My scope has a hole in its front plate to >> accommodate a standard BNC plug, but it's not big enough for this >> oversized plastic variant. >> >> This probably saves several cents per probe, but created a problem I >> didn't need. >> >> Sylvia. > > I had a similar problem with some long forgotten piece of SCADA > hardware. The BNC plugs fit, but they were so close together that > even the official insertion/removal tool didn't fit. However, this > was using a 50 ohm system, not the much higher impedance of a scope > probe. > > I created an adapter of sorts to elevate every other connector. It > was a UG-88C/U plug with BNC panel mount receptacle crammed into the > plug. A short piece of bare wire connected the center pins and an > ugly solder blob connected the grounds: > <https://www.newark.com/amphenol-rf/ug-88c-u/rf-coaxial-bnc-plug-50-ohm-cable/dp/04M6671> > <https://www.newark.com/amphenol-rf/31-10/connector-bnc-bhd-jack-str-50/dp/38F1322?st=bnc%20panel> > The resulting adapter added about 1 inch to the length of the 50 ohm > connection. Whether the added capacitance will cause problems on your > oscilloscope will need to be determined. > > If you want to just see if such an adapter has a chance of working, > try connecting a BNC M-M adapter (UG-491A/U) to a BNC F-F adapter > (UG-914/U). This will extend the line length by 1.75 inches. If it > works, build a shorter adaptor. > >
I bought a male to male adapter and a female to female adapter, and joined them together. Seems to work OK for the kinds of frequency I deal with - it's only a 20MHz scope anyway. The extra length of metal attached to the socket does make it easier to damage the socket though. Sylvia.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On 13-Nov-21 2:59 am, John Robertson wrote:
> > On 2021/11/11 11:31 p.m., Sylvia Else wrote: >> On 12-Nov-21 1:01 pm, Jeff Liebermann wrote: >>> On Thu, 11 Nov 2021 14:48:38 +1100, Sylvia Else <sylvia@email.invalid> >>> wrote: >>> >>>> Bought a couple of oscilloscope probes today to replace those >>>> damaged/lost. >>>> >>>> They don't fit, because the plastic surround exceeds the specified >>>> diameter for a BNC plug. My scope has a hole in its front plate to >>>> accommodate a standard BNC plug, but it's not big enough for this >>>> oversized plastic variant. >>>> >>>> This probably saves several cents per probe, but created a problem I >>>> didn't need. >>>> >>>> Sylvia. >>> >>> I had a similar problem with some long forgotten piece of SCADA >>> hardware.&nbsp; The BNC plugs fit, but they were so close together that >>> even the official insertion/removal tool didn't fit.&nbsp; However, this >>> was using a 50 ohm system, not the much higher impedance of a scope >>> probe. >>> >>> I created an adapter of sorts to elevate every other connector.&nbsp; It >>> was a UG-88C/U plug with BNC panel mount receptacle crammed into the >>> plug.&nbsp; A short piece of bare wire connected the center pins and an >>> ugly solder blob connected the grounds: >>> <https://www.newark.com/amphenol-rf/ug-88c-u/rf-coaxial-bnc-plug-50-ohm-cable/dp/04M6671> >>> >>> <https://www.newark.com/amphenol-rf/31-10/connector-bnc-bhd-jack-str-50/dp/38F1322?st=bnc%20panel> >>> >>> The resulting adapter added about 1 inch to the length of the 50 ohm >>> connection.&nbsp; Whether the added capacitance will cause problems on your >>> oscilloscope will need to be determined. >>> >>> If you want to just see if such an adapter has a chance of working, >>> try connecting a BNC M-M adapter (UG-491A/U) to a BNC F-F adapter >>> (UG-914/U).&nbsp; This will extend the line length by 1.75 inches.&nbsp; If it >>> works, build a shorter adaptor. >>> >>> >> I bought a male to male adapter and a female to female adapter, and >> joined them together. Seems to work OK for the kinds of frequency I >> deal with - it's only a 20MHz scope anyway. >> >> The extra length of metal attached to the socket does make it easier >> to damage the socket though. >> >> Sylvia. > > How about just build a short BNC plug and receptacle extension, with a > short length of cable between them? As you say it is only 20mHz... > > John :-#)#
Could do, but that would have added yet another thing to the stack of things I needed to do before I could get on with what I was actually wanting to do. Sylvia.
On Fri, 12 Nov 2021 18:31:07 +1100, Sylvia Else <sylvia@email.invalid>
wrote:

>On 12-Nov-21 1:01 pm, Jeff Liebermann wrote: >> If you want to just see if such an adapter has a chance of working, >> try connecting a BNC M-M adapter (UG-491A/U) to a BNC F-F adapter >> (UG-914/U). This will extend the line length by 1.75 inches. If it >> works, build a shorter adaptor.
>I bought a male to male adapter and a female to female adapter, and >joined them together. Seems to work OK for the kinds of frequency I deal >with - it's only a 20MHz scope anyway.
Those are the connectors (UG-491a/u and UG-914/u) I suggested. At 20MHz, that added capacitance shouldn't create a major problem. My capacitance guesser indicates that the 1.75 inches of adapters adds 3.7pF.
>The extra length of metal attached to the socket does make it easier to >damage the socket though.
I should have mentioned that my suggestion was intended to be a temporary solution and sufficient only until you are able to either modify the plastic sleeve or replace the scope probes with something that fits. If the plastic locking sleeve can be removed, it might be possible to use a lathe to turn it down so that it fits. If a lathe is not available, a drill press and a hand file. Drivel: My favorite diversion from what I'm suppose to be doing is fixing my test equipment before I can use it. That's the price I pay for using 40 year old equipment and 1 year old imported junk. Good luck. -- Jeff Liebermann jeffl@cruzio.com PO Box 272 http://www.LearnByDestroying.com Ben Lomond CA 95005-0272 Skype: JeffLiebermann AE6KS 831-336-2558
On Friday, November 12, 2021 at 11:03:51 PM UTC-5, jeff.li...@gmail.com wrote:
> On Fri, 12 Nov 2021 18:31:07 +1100, Sylvia Else <syl...@email.invalid> > wrote: > >On 12-Nov-21 1:01 pm, Jeff Liebermann wrote: > >> If you want to just see if such an adapter has a chance of working, > >> try connecting a BNC M-M adapter (UG-491A/U) to a BNC F-F adapter > >> (UG-914/U). This will extend the line length by 1.75 inches. If it > >> works, build a shorter adaptor. > > >I bought a male to male adapter and a female to female adapter, and > >joined them together. Seems to work OK for the kinds of frequency I deal > >with - it's only a 20MHz scope anyway. > Those are the connectors (UG-491a/u and UG-914/u) I suggested. At > 20MHz, that added capacitance shouldn't create a major problem. My > capacitance guesser indicates that the 1.75 inches of adapters adds > 3.7pF. > >The extra length of metal attached to the socket does make it easier to > >damage the socket though. > I should have mentioned that my suggestion was intended to be a > temporary solution and sufficient only until you are able to either > modify the plastic sleeve or replace the scope probes with something > that fits. If the plastic locking sleeve can be removed, it might be > possible to use a lathe to turn it down so that it fits. If a lathe > is not available, a drill press and a hand file. > > Drivel: My favorite diversion from what I'm suppose to be doing is > fixing my test equipment before I can use it. That's the price I pay > for using 40 year old equipment and 1 year old imported junk. > > Good luck. > -- > Jeff Liebermann je...@cruzio.com > PO Box 272 http://www.LearnByDestroying.com > Ben Lomond CA 95005-0272 > Skype: JeffLiebermann AE6KS 831-336-2558
Re: drivel: Just curious, What is your preference? I tend to fix my 40 yo 'junk'...Including tube testers, tek 7904 and 475, VTVM (who uses them anyway?) My one 'prize' is my Agilent mso-x0354 @ 1GHz..I'd hate to have to repair that if it became damaged. In some respects, repairing old gear is somewhat 'therapeutic'... To each their own... J
On Sat, 13 Nov 2021 15:06:42 -0800 (PST), Three Jeeps
<jjhudak4@gmail.com> wrote:

>On Friday, November 12, 2021 at 11:03:51 PM UTC-5, jeff.li...@gmail.com wrote: >> Drivel: My favorite diversion from what I'm suppose to be doing is >> fixing my test equipment before I can use it. That's the price I pay >> for using 40 year old equipment and 1 year old imported junk.
>Re: drivel: Just curious, What is your preference? >I tend to fix my 40 yo 'junk'...Including tube testers, tek 7904 and 475, VTVM (who uses them anyway?) >My one 'prize' is my Agilent mso-x0354 @ 1GHz..I'd hate to have to repair that if it became damaged. >In some respects, repairing old gear is somewhat 'therapeutic'... >To each their own... >J
<http://www.learnbydestroying.com/jeffl/pics/home/test-equip-mess.jpg> <http://www.learnbydestroying.com/jeffl/crud/scopes-to-be-fixed.jpg> It's worse now. I closed my office at the end of last year and moved everything to my house. A year later, I'm still sorting through the junk, trying to find things, and fixing what I can. The workbenches are all buried under piles of junk. No sense in cleaning them up because there's no place to store the junk. Under such circumstances, the guiding principle is to not add anything new. I much prefer to fix the old test equipment. For my purposes, which is not state of the art, I don't need the latest test equipment. In the past, when I needed the latest greatest, there were friends and former employers who would allow me to use their labs or borrow their test equipment. During the Covid area, that's no longer possible. Since I can't afford to buy or rent new test equipment, my most economical option is to fix what I can get, and keep my equipment running. Second best is to buy something that may or may not do the job on eBay. I have a few Made in China pieces of test equipment (RF noise generator, sweep generator, cavities, VNA, LRC meter, battery discharge tester, etc). Most are under $100 which is much cheaper than the equivalent vintage or modern equipment. The problem is that fixing test equipment takes time away from paying projects. The deadline is always closer than predicted making diversions such as test equipment repair, a money losing proposition. When pressed, I often resort to borrowing what I need. Fortunately, I've been lucky to have friends with well equipped labs. Unfortunately, I usually end up exchanging the favor by fixing their chainsaws and emergency generators. There might have been a time when fixing old test equipment was "therapeutic" but currently, it's an exercise in frustration. Finding old repair components is becoming difficult and creative substitutions are becoming the norm. Bottom line: If you can, fix it and keep it out of the landfill. If you can't, borrow something similar. If you have time and money, buy new test equipment. -- Jeff Liebermann jeffl@cruzio.com PO Box 272 http://www.LearnByDestroying.com Ben Lomond CA 95005-0272 Skype: JeffLiebermann AE6KS 831-336-2558
On 12/11/2021 15:59, John Robertson wrote:

<snip>
> > How about just build a short BNC plug and receptacle extension, with a > short length of cable between them? As you say it is only 20mHz... > > John :-#)#
No, 20 MHz. FFS. -- Cheers Clive