Good sharp fine tip multimeter probes with very flexible leads

[rfmerrill]

I've been a pretty big fan of these probes: https://www.amazon.com/Pomona-Test-Lead-Precision-Probe/dp/B003UZJ3EQ/ref=cm_cr_arp_d_product_top?ie=UTF8

But my coworker doesn't like them and they have a good point in that they don't seem to consistently make good contact. When you are measuring resistance the resistance sometimes jumps above the value for a bit. Have noticed this with several sets of the same probes and it is quite disappointing considering the brand and the price.

My coworker bought a set of much bigger probes which also have sharp tips but I have a few things I dislike about those: The tips bend easily, the shrouds make them too big to fit in the probe holders on the back of the meter, and the cable is a bit more cumbersome (it's a more typical probe lead).

I'm mostly wondering if I'm missing something or doing something really wrong that I'm getting unreliable resistance readings from these probes or if there are better ones I can buy.

[bob91343]

Most unreliable resistance measurements are caused by corrosion.  The plating on the tip may be poorly done and rust or other oxide corrupts the surface.  Possibly the tips are just dirty.

You can't make good measurements below a few Ohms with most meters due to variability in contact resistance and probe lead resistance.  A better way is to cobble up a 4-wire ohmmeter, which I have done.  It uses a wall wart and one little 3 terminal IC and maybe two resistors.  You use any test leads you like with no problems, but of course now it's four leads not two.  I made them up from some old shielded audio cable and a couple of alligator clips.  So the shield is one lead and center is the other, two of them.  You use any DVM to get the reading.

Some DVMs come with decent probes.  The old VOMs used simple probes, easy to use and repair.

[voltsandjolts]

The Pomona 6275, 6341, 6342 are notorious for dodgy connection straight out of the box, just search the forum.

e.g.

Pretty sure I wrote flame email to Pomona because of the aluminum tube in the Pomona 6341,6342,6275 series. Awful connection for ohmmeter measurements. No mention of aluminum in their datasheet either 
and $71 CAD at Digikey. OUCH

It is such a shame because the shape and form of the probes are perfect for me.
I have a few pairs but I can't trust them.
I even tried soldering the tips in place on one pair but it didn't help, the bad connection is internal.

I wrote to them and their reply was simply 'speak to distributor' they didn't care they have a big design flaw. 

Maybe if Dave demonstrated it in a 'probe shootout video' it would embarrass them into doing something about it!

[Electro Detective]

When it comes to multimeter probes not doing their job, and or making more work for the user whilst trying to do work, 

it's up to the user to ensure the multimeter sockets and leads are tarnish and gunk free,

and proper mechanical tension so that the lead plugs are mating properly with the meter.

Probe tips need to be clean, in any manner that works for the user, to ensure close to zero (0.2  ?) resistance.


Give me a nice lead set, or cheapo bin jobs to sort out, and they will perform the way I expect.

FWIW: what you are probing may have layers of crap on it, don't just toss the blame at the sharp/blunt/dirty probes.

The multimeter manufacturers supply a warranty, not a maintenance plan to keep the meter and leads working Day One.

That's the users job,
or buy a new meter every six months, which is no problem for corporats,
but no good for urban battlers 
 

[voltsandjolts]

Clean them all you like, these Pomona probes are dodgy before you even open the packaging.

[Electro Detective]

Does ThreeHungLow produce them nowadays ? 

[voltsandjolts]

Hah, yeh!
Alledgedly they are made by Ponoma a.k.a Fluke a.k.a Danaher but who knows these days, maybe they are just a rebrand of ThreeHungLow.
For the price, they should be much better.

[Fraser]

I purchased Probemaster fine spring loaded tip probes through Simon on this forum and have not looked back. They are excellent quality and the spring loaded tips are perfect for keeping the tip where you want it, there are ‘solid’ tips included as well.

https://probemaster.com/dmm-multimeter-test-leads/

My probe set.....

https://probemaster.com/spring-loaded-micro-tip-test-lead-kit/

They are the best test leads that I have used.

I have a set of the Pomona 6341 fine tipped probes and whilst they work for me, they do appear fragile. I treat them with great care !

Fraser

[Hydron]

Can confirm everything (other than the alleged internal aluminium tube, I didn't know _why_ they were so bad until now) about the Pomona ones, from multiple sets - iffy contact straight out of the box. Basically unusable for accurate resistance measurement under a few kohms, though you'd normally get away with voltage measurements, which is what I generally restrict mine to. It's a real shame, as they are a great form factor for poking around a dense PCB.

[Electro Detective]

I've got all manner of multimeter leads, from stiff cheapos, progressing up to the standard Fluke, Brymen, Appa leads, no-name/weird name  silicone knockoffs,
the $20 Jaycar silicone types (not bad at all )
and the overpriced Fluke flagship set with the retractable tip cover thingies   (half price sale = couldn't resist  ) 

Cleaned, lubed and tensioned properly, they ALL pretty much perform identically when touched and slid along a bar of clean stainless steel or copper tube etc.

Where they differ is in the handling and entanglements, not still/moving about meter reading changes,
and how well they dig in to dirty contacts and stay 'dug'

FWIW if you use/abuse even the best sharp probes, thy will get just as blunt or ball up over time as the cheaper prods,
and might give you even worse readings in that sorry state, than the less used 'tangled ball of spaghetti' cheapies chucked in the corner 

Once a decent set of probes lose their stabbing power, rather than toss or re-purpose them, I wack on a magnifier and fine file and re-shape them back to usability,
especially after an oopsie zap has obliterated and blackened the tip end    
and keep a watch the filed tips don't tarnish/corrode and blunt a lot quicker once you go down that filing path

i.e. we can bang heads and slag products, but the reality is blunt and corrosion/tarnish that's hard to see, will always shaft any cheap or top spec multimeter, especially on low level readings.

What we really need is either replaceable tips (but not at FlooQ price markup hell  )

or better still, slip on tips with various shapes etc to better suit the prodding at hand

[0culus]

https://probemaster.com/


No, I'm not affiliated with them. Yes, I own two pair of their retractable shield DMM leads to use with old voltmeters that don't support shrouds. Very nice stuff, will be buying more. 

[rfmerrill]

I'm talking to Pomona's product manager and their side of the story seems to be that some contact issues are expected due to the stainless steel probe tips (I'm guessing the advantage there is hardness, they're designed to be pressed hard against whatever you're measuring) but some of the ones they've shipped in the past (which fits the timeline for the other two pairs I've bought) had plating defects. So if you buy one now and it has a recent manfuacturing date you might get a bit better performance.

Unfortunately the only non-stainless tips they offer are all spring-loaded, which is useful sometimes but not always :/

BTW I bought those probemaster probes and one gripe I have is that the spring-loaded tips actually fully retract into the probe housing. You can pull them out slightly but then they'll slide back in if you apply enough pressure.

I'm guessing when it comes to really fine probes it's always going to be a tradeoff between good contact and durability.

[voltsandjolts]

I'm talking to Pomona's product manager and their side of the story seems to be that some contact issues are expected due to the stainless steel probe tips

That's just their way of telling us "you're not using them right, press harder".
I say BS.
The probes are intermittant with solid tips, sprung tips, gold plated or stainless.
If Pomona have a big stock of these and won't admit a problem - then shame on them.
If they are still making these in production, for goodness sake stop and fix 'em.

[2N3055]

I'm talking to Pomona's product manager and their side of the story seems to be that some contact issues are expected due to the stainless steel probe tips (I'm guessing the advantage there is hardness, they're designed to be pressed hard against whatever you're measuring) but some of the ones they've shipped in the past (which fits the timeline for the other two pairs I've bought) had plating defects. So if you buy one now and it has a recent manfuacturing date you might get a bit better performance.

Unfortunately the only non-stainless tips they offer are all spring-loaded, which is useful sometimes but not always :/

BTW I bought those probemaster probes and one gripe I have is that the spring-loaded tips actually fully retract into the probe housing. You can pull them out slightly but then they'll slide back in if you apply enough pressure.

I'm guessing when it comes to really fine probes it's always going to be a tradeoff between good contact and durability.

That is bull.
Bad contact is somewhere between cable, crimped aluminum tube on copper cable, or between aluminium tube and tips (just a snug fit).

But for voltage measurements they are good enough. I really hate TOO soft and TOO thin cables, that are TOO flexible and keep on getting in the way, getting in the   DUT, getting caught on components. They would be better if they were a bit thicker and stiffer, so they fall nicely in a nice radius behind my hand. The way they are now, they behave like a wet thread... It's annoying.
I actually use modular cables with sharp tips lately, not those little Pomona ones. Which is a shame because handle size is nice for fine stuff..

[nukie]

The product manager probably never even handled the probes before. It's such a tight fit how can it cause connection issue. If so then all the pogo pins test jigs in this world will be full of problems. These crooks are FULL OF LIES.

My sex on stick probes as with many on this forum comes with STD. I would guess that there is a manufacturing defect where the wire joins the pin sockets. I tested my negative probe it was perfect. My positive probe not so happy. The resistance would jump up and down whenever the cable was tugged. The only solution is so solder the cable directly to the pin socket but the material used for moulding the handle does not tolerate soldering temperature.

Anyway the Pomona 6341 / Fluke TL910 is garbage don't buy it. The probe masters seems to be a better product.

[Fraser]

I am sat here reading the latest posts on these Pomona probes and a thought popped into my head. If someone is willing to risk their probes and also owns a thermal camera.... they could connect the probe and its associated cable across a constant current lab PSU and pass a decent current through the assembly whilst watching it with the thermal camera. The area of poorest conduction or contact should become very clear in the thermal image if the camera and current level is setup correctly.

A risky action would be to ‘flash’ the Probe assembly with a high current pulse to see if an arc/spot weld can be formed at the point of highest resistance. Worth a go if the probes are of no use if not fixed.

Fraser

[nukie]

According to this users post https://www.eevblog.com/forum/repair/pomona-test-leads-repeated-failure/msg1535624/#msg1535624 another post related to Pomona probe cable failure...

So there is a brass barrel in the probe handle. This brass barrel should not twist or move inside the handle as it is molded over quite tightly and stickly.  The connection between the stainless tip socket and the brass body is very robust. The only suspect is the wire. Hey so called Product Manager at Pomona I just did your job for you!! Now your next step is to rectify the problem!

The Fluke TL910 test leads are not much better, the wire keeps breaking "inside" the probe ! After the second set of probes failed I hacked one apart. Inside the probe body there is a brass barrel to hold the replacable probe tips and the wire is soldered onto the end of the barrel and that is where it fails. If fluke had used a bit of common sense and crimped the wire they might have been decent probes.

here's another member's fix
https://www.eevblog.com/forum/testgear/finest-possible-multimeter-test-leads/msg720753/#msg720753

Looking at this Xray image... https://www.eevblog.com/forum/testgear/smt-probes-comparison-probe-master-8151-vs-pomona-6341-tl910-inc-x-ray-images/msg1017621/#msg1017621

And this genius did a half cut dissection sacrifice his cable for everyone here! Thank You!
https://www.eevblog.com/forum/testgear/smt-probes-comparison-probe-master-8151-vs-pomona-6341-tl910-inc-x-ray-images/msg1030927/#msg1030927

I did a big tug and twist on the poor wire and it did fixed the problem but I am not confident with reliability. Im tempted to drill a hole near the end of the internal brass tube where the solder joint is. Redo the joint and fill the hole with silicon for future maintenance  .

Anyway post like these are great warning to stay away from the Pomona 6341 / Fluke TL910 https://www.eevblog.com/forum/testgear/fluke-tl-910-test-leads-poor-quality/msg327873/

[voltsandjolts]

Yeh, I chopped one in half also:



The wire crimp at the top of the internal brass tube seems fine.
But the other end of the brass tube is crimped to an aluminium tube....who thought that was a good idea? The accountant?
The replaceable tips then slide into the alloy tube...also a bad idea.

With some keyhole surgery it might be possible to put some solder on the brass/alloy crimped joint but otherwise bypass wires are the only way.

Pomona:

[rfmerrill]

So the replacement sets arrived and they were nice enough to throw in a full tip set with each one.

I can confirm I find basically no issue with the springloaded gold tips. Basically perfect resistance reading every time, so far at least. I actually kind of prefer them to the probemaster probes, but they're about equivalent so I don't mind either.

When I was comparing the several-year-old pomona pair to the brand new ones I did notice that the old ones seemed to have a much looser fit on the tips, and they're all a *lot* looser than the probemaster ones (which are tight all the way, whereas the pomona tips are loose until they're most of the way in).

They did also throw in a sample of the 7619a test probes which I do rather like although they are a very different type of product to these.

The Mueller probes my coworker bought a while back appear to be these, but I can't find where to buy them: https://www.muellerelectric.com/products/BU-2741-R-36-2

[Brutte]

When you are measuring resistance the resistance sometimes jumps above the value for a bit.

I think measuring 2-lead resistance with 1000V 10A probes indicates the problem itself.
You want one set of convenient probes for 100nA to 10A and 10uV to 1kV? That is a really niche market, but I can imagine a trip to Mars when I can take one set only, I'd probably pick this Pomona. However, on Earth...

For <100mA currents and <50V voltages I use 2x1m long stranded AWG28 (stripped from USB cable) with brass 4mm banana plug at one end and crimped stainless steel needle at the other end. If you cannot punch through the oxide with stainless insuline needle then there is no hope for that circuit.

[eKretz]

I have a set of these and mostly ignored them because of the high and seemingly variable resistance. Then one day I started trying to figure out where the problem was. I held the tips in contact while connected to my meter in resistance mode. Started flexing and wiggling the cables looking for possible variability that might indicate a break in the wires. Very slight changes in resistance, nothing significant.

Then I flexed the body of the probes up near where the wire exits. Instant change for the better! I then took both probes and sort of rotated/twisted them while flexing that end again. Afterward, indicated resistance was under 0.1 ohm, and stayed there. I would say there's some corrosion going on somewhere internal to the probe handle/grip area. Now, every time I use them I do that flexing while rotating thing just before use by force of habit and no more problems.

[2N3055]

I have a set of these and mostly ignored them because of the high and seemingly variable resistance. Then one day I started trying to figure out where the problem was. I held the tips in contact while connected to my meter in resistance mode. Started flexing and wiggling the cables looking for possible variability that might indicate a break in the wires. Very slight changes in resistance, nothing significant.

Then I flexed the body of the probes up near where the wire exits. Instant change for the better! I then took both probes and sort of rotated/twisted them while flexing that end again. Afterward, indicated resistance was under 0.1 ohm, and stayed there. I would say there's some corrosion going on somewhere internal to the probe handle/grip area. Now, every time I use them I do that flexing while rotating thing just before use by force of habit and no more problems.

Problem is that probe tips are sitting inside aluminium tube.. Aluminium oxide is fabulous insulator. By twisting and wiggling probes and reinserting tips you scrape surface oxides and it gets better. After some time it gets worse. And so on...

Probes have nice form factor for small stuff. They only had to do one thing, tosses, to extend brass tube that they crimped cable to all the way to the tip...
Also, I find cables TOO soft and too thin, they are like wet thread, getting in the way...

[eKretz]

I have a set of these and mostly ignored them because of the high and seemingly variable resistance. Then one day I started trying to figure out where the problem was. I held the tips in contact while connected to my meter in resistance mode. Started flexing and wiggling the cables looking for possible variability that might indicate a break in the wires. Very slight changes in resistance, nothing significant.

Then I flexed the body of the probes up near where the wire exits. Instant change for the better! I then took both probes and sort of rotated/twisted them while flexing that end again. Afterward, indicated resistance was under 0.1 ohm, and stayed there. I would say there's some corrosion going on somewhere internal to the probe handle/grip area. Now, every time I use them I do that flexing while rotating thing just before use by force of habit and no more problems.

Problem is that probe tips are sitting inside aluminium tube.. Aluminium oxide is fabulous insulator. By twisting and wiggling probes and reinserting tips you scrape surface oxides and it gets better. After some time it gets worse. And so on...

Probes have nice form factor for small stuff. They only had to do one thing, tosses, to extend brass tube that they crimped cable to all the way to the tip...
Also, I find cables TOO soft and too thin, they are like wet thread, getting in the way...

Nope - at least in my case - it is on the other end of the probe that I did the twisting and flexing - where the wire exits. I too assumed it was the area that the tips went in that was causing the high/varied resistance issues and even went so far as to clean and DeOxit those. That didn't help.

[nukie]

I think the other end is stainless tubing, at least for my set. I dont see it as aluminium because it's particularly soft and its easily damaged when small force is applied especially with such thin tubing.

My probes issue was fixed by tugging and twisting the wires near the end of the handle. The crimp connection near the wire is the problem. Probe Masters are soldered not crimp. So its much better solution.

[2N3055]

I think the other end is stainless tubing, at least for my set. I dont see it as aluminium because it's particularly soft and its easily damaged when small force is applied especially with such thin tubing.

My probes issue was fixed by tugging and twisting the wires near the end of the handle. The crimp connection near the wire is the problem. Probe Masters are soldered not crimp. So its much better solution.

It is aluminium and a very soft one. You can shave it with a blade like a butter..