Problems we don't need

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.

Reply to
Sylvia Else
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Sylvia Else snipped-for-privacy@email.invalid wrote in news: snipped-for-privacy@mid.individual.net:

Dremel is your friend.

Reply to
DecadentLinuxUserNumeroUno

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:

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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.

Reply to
Jeff Liebermann

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.

Reply to
Sylvia Else

The Rigol probes may also have this issue on other scopes ~ wider plastic boss.

My bench usually requires a daisy chain on at least one signal line, so BNC 'T' or 'F' adapters usually hang off at least one scope socket, usually a trigger input or output.

They can act as a feed-through for physically incompatible probe connectors, in a pinch.

If the probe has programming pins, well . . .

RL

Reply to
legg

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 :-#)#

Reply to
John Robertson

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.

Reply to
Sylvia Else

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.

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.

Reply to
Jeff Liebermann

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

Reply to
Three Jeeps

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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.

Reply to
Jeff Liebermann
<snip>

No, 20 MHz. FFS.

Reply to
Clive Arthur

What does that mean?

Sylvia.

Reply to
Sylvia Else

I had the capitals incorrect - I put mHz, he corrected to MHz, MHZ is also correct. mHz is just wrong...

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FFF is For F...(s) Sake.

John ;-#)#

Reply to
John Robertson

Oh, yes. Thanks.

Sylvia.

Reply to
Sylvia Else

Sylvia Else snipped-for-privacy@email.invalid wrote in news: snipped-for-privacy@mid.individual.net:

Well it ain't Fast Fourier FuckForm. :-)

Reply to
DecadentLinuxUserNumeroUno
<snip>

MHZ is certainly not correct!

mHz (millihertz) is commonly used in seismometry for example.

Basic stuff like this matters.

Reply to
Clive Arthur

It varies a lot between disciplines. I was reading a finanical article which used "m" for millions, then later in the same piece used "mm" for million as in "thousand - thousand". I expect each usage was from a source and the author never bothered to care that they were using different symbols.

Reminds me of a Reader's Digest joke about an American visiting Scotland I think and was telling a story in a bar (excuse me, pub). There were three different mistranslations that resulted in his story becoming a "tall tale". The last was so egregious the patrons congratulated him on being the biggest liar ever in the bar. I believe it had to do with the different definition of "billion" being a thousand million in the US and a million million in the UK (at least at that time).

Looks like we are heading for simple news reporting becoming the bigger liar with the confused abbreviations for million.

Not sure the Brits would ever notice. They did manage the transition from the old p to the new p and such. Does "Bob" still have any monetary meaning? I did find Andy Capp to be rather humorous asking for "a bob" and all. It was much more recently I figured out why he called everyone Gov'.

Reply to
Rick C
<snipped>

I think MMBOPD is still used to mean 'million barrels of oil per day'.

Actually, the old penny was a 'd', supposedly from 'denarius'. The pound sign was basically a fancy 'L' and the symbols for pounds, shillings and pence were based on librum, solidus and denarius.

[The ASCII character set didn't include the pound symbol and often this would print as an octothorpe or hash symbol, thus leading to rather strained jokes about the connection between LSD and hash.]

Does "Bob" still have any monetary meaning? I did find Andy Capp to be rather humorous asking for "a bob" and all. It was much more recently I figured out why he called everyone Gov'.

Very rarely you might hear the expression 'as bent as a nine bob note', otherwise it's gone the way of the tanner. Incidentally, the old two bob bit (24d or 10p) was also called a 'florin' and was some sort of early experiment with decimalisation.

And one pound sterling of old pennies - that's 240 of them - would weigh five pounds avoirdupois. Three pennies to the ounce.

Reply to
Clive Arthur

Sorry, cocked up the quoting. The 'Does "Bob" still... paragraph is of course Rick's.

Reply to
Clive Arthur

Yes.

Every time I read about a power station producing some number of mW, I wonder whether someone got scammed.

Sylvia.

Reply to
Sylvia Else

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