Do you keep your scope probes connected all the time?

[dadler]

Just wondering what the common practice is.

My gut tells me that after a number of connect-disconnect cycles, the BNC connectors on scopes will wear and the some degradation will occur. I'm sure the connectors are rated for a certain number of cycles.

So I generally keep them connected all of the time. This works fine, except I have two cats that love to chew on cords.

I know Dave's solution to this (cat) problem would involve two large paper bags and a vehicle in drive--but I was wondering what everyone does. Do you leave your scope/DMM/etc probes connected most of the time?

[Vgkid]

I unplug mine. If the cheap chinese probes can survive semester after semester, years on end. Then you should be good. The only parts on probes that seem to die are switches, and broken probe tips

[bithead9]

I keep mine plugged in most of the time. 

[pickle9000]

My lazy factor is high, always plugged in.

[ivan747]

I disconnect them because I store the scope in its bag so it doesn't rust in my area's weather.

As for the cat problem, get him a chew toy, an already broken thing he loves to chew on, and get it near the oscilloscope probes. Now every time the cat gets in chewy mood, just yell at him if he chews on the cord, but ignore him if he chews on the chew toy. Works fine for me  At least when I watch him  The cat usually enters chewy mood when I am around and when he's on purr mode, I don't know how yours behaves. I don't get broken cables anymore.

[pickle9000]

A little Habanero juice on the probe cable will keep the cat off.

[TiN]

Lol @ cat problem (I don't have one). Could be expensive chewing experience if one have high-speed probes

Having P7380 probes in their bags disconnected usually, use them only when needed (which is rare),
while more general purpose probes P6245's connected to scope all time.
Logic analyzer P6810 connected at all times at frame, while others store in box (rarely use).

[Richard Crowley]

BNC connectors aren't all that fragile.
OTOH, leaving the weight of the probe cable pulling against the strain-relief is certainly more stressful, and more likely to cause premature failure, IMHO.

[T3sl4co1l]

I don't think I've had a BNC wear out -- though I have discovered a few of my tees or terminators with bum inner grounds...

I have had probes die though.  Those Chinese ones seem to last about a year before the inner conductor frays and goes intermittent.  Taking it on and off all the time would make that worse.

Tim

[rx8pilot]

I will more likely damage the cable or the tip before the BNC has an issue. I also have $500 - $2000 probes that need to be cares for. I keep them in small Pelican cases until they are needed.

[smjcuk]

I use cheap Wittig probes that cost $10 a set for 100MHz. At this price they are disposable so I tend to unplug them and chuck them in a large sandwich box in a drawer when done. Parasitic capacitance isn't great on these but I've learned to probe after any buffering rather than load the actual circuit I'm looking at if its sensitive.

To be honest I worry more about the BNC connectors on the scopes myself as they are universally complete bastards to replace. My cheap goldstar scope has a rather loose channel 2 to fix on the TODO list.

[pascal_sweden]

My gut tells me that after a number of connect-disconnect cycles, the BNC connectors on scopes will wear and the some degradation will occur. I'm sure the connectors are rated for a certain number of cycles.

What about putting an extra BNC plug on the BNC connectors of the scope, and remove the probe from the extra BNC plug? This way the extra plug might wear out, but not the BNC connectors on your scope. The frequency of removing the extra BNC plug (when it actually would wear out) is much lower than the frequency of removing the probe from the extra BNC plug. Several years versus daily.

[rob77]

probes plugged in all the time on my bench scope and disconnect the probes after use for my handheld scope.
also got a cable chewing cat - but the cat is banned from my "lab"

[tautech]

To be honest I worry more about the BNC connectors on the scopes myself as they are universally complete bastards to replace. My cheap goldstar scope has a rather loose channel 2 to fix on the TODO list.

You are quite right to be concerned for the BNC sockets, other than the electrical integrity the have to handle a lot of physical stress over their life.

What about putting an extra BNC plug on the BNC connectors of the scope, and remove the probe from the extra BNC plug? This way the extra plug might wear out, but not the BNC connectors on your scope. The frequency of removing the extra BNC plug (when it actually would wear out) is much lower than the frequency of removing the probe from the extra BNC plug. Several years versus daily.

IMO you'd need to check the manner in which the BNC's are secured first. Some only had a 2 lug socket soldered to the PCB and were prone to breaking one or both those lugs off. Depending on the scope's PCB you might have a good ground plane in which to strap the sockets to for better physical strength.
Early Tek DSO's were bad for this.

I'm always anxious with any probe with a large compensation/termination box because of the physical stress on the BNC.

[daddario]

I only remove probes when I need to connect something else - otherwise it'd be silly as I use my scope effectively every single day. I generally also avoid unnecessary cycling of multimeter probes as no connector is eternal - yes, I've had to change sockets even on Flukes. I tend to keep one go-to meter with my favourite TL175 probes connected, while always unplugging all straight banana connectors from handheld DMM's after a job is done as I am a bit paranoid about something falling from the shelves and right upon them. When carrying equipment around, all cables get unplugged(including multimeter probes) and wrapped in a nice over-under method, like all the rest of the cables.

[SeanB]

Extension units, or adaptors for various connectors. I have a few fused probe protectors, designed to both do connector interfacing and to provide protection for the input using a small in line fuse in the body. Originally they were common on spectrum analysers as an accident with the press of transmit will blow the SA fast, but these with a 50mA fuse help protect against that, or at least the blown fuse will tell you the SA is now cooked.

[rollatorwieltje]

I usually leave mine connected, but really I'm not too worried about the BNC jacks themselves. I've only had plugs fail, the jack is usually fine (unless it completely rips off the board, the great days of coax ethernet).

I'm more worried about the USB connector. So little mechanical support...

[ivan747]

I usually leave mine connected, but really I'm not too worried about the BNC jacks themselves. I've only had plugs fail, the jack is usually fine (unless it completely rips off the board, the great days of coax ethernet).

I'm more worried about the USB connector. So little mechanical support...

While on that topic, let's talk about SMD 3.5mm auxiliary ports on cars 

[pascal_sweden]

On some phones or tablets, there is plenty of room to use a mini USB connector.
Still the manufacturers only use micro USB connectors. These connectors are so sensitive that you really have to be careful every time you insert the cable. But maybe it is part of their planned obsolence strategy?

[rsjsouza]

Since ages ago when I worked on the university lab, I have remove the cables after a day's work as the danger of inavertently yanking the cables laying around on the bench (and some folks even left them hanging past the bench sides!) was pretty high.

These connectors are so sensitive that you really have to be careful every time you insert the cable.

Believe it or not, micro USB connectors allow a higher number of insertions than mini USB. In my experience I have seen a larger share of mini USB connectors damaged due to several reasons (bent pins, foreign objects inside, etc)

[Fungus]

Believe it or not, micro USB connectors allow a higher number of insertions than mini USB.

And the mini ones allow a higher number of insertions than the big chunky ones.

http://en.wikipedia.org/wiki/USB#Durability

Plus the micro connectors are designed to break the cable, not the socket. Cables are easy to replace.

[German_EE]

One of my cats sometimes chews mains cables, he likes to live dangerously.

[MarkL]

I keep them connected all the time and I hang them on probe holders on the side of the rack to keep them out of the way and the full weight of the cable off the probe and compensation box.  It's very convenient to grab one and start measuring.  I keep the hat on the probes to prevent being stabbed by the tips.

The holder is Tektronix 352-0351-00.  Each one holds 2 probes and was included in the accessories bag with P6131 probes I bought years ago.

Those are Agilent probes in the picture.

[smjcuk]

One of my cats sometimes chews mains cables, he likes to live dangerously.

My uncle was killed in a house fire caused by a dog chewing a cable (so the fire forensics people reckon based on the fact it was welded to the cable face first). I'd get rid of the cat. Poisonous dust, parasites, pissing on your data sheet folders (this happened when I had a cat) and leaving dead things around the house. Yuck no more. fuzzy death machines.

[cdev]

If you live in an area with cold winters, you should avoid hanging anything which might get rusty or corroded on your outside walls, always hang cables and place electronics that needs to be functional on an interior wall. The reason can easily be shown in cold weather with a humidity sensor. There is a microclimate/boundary layer along walls where the temperature can be substantially lower and the humidity can easily go up 10 percentage points or more.

The same thing goes for storage.  This can be reduced by circulating the air, ideally (*after* doing a good initial cleaning!) using an air cleaning device.