Author Topic: hard, sharp meter probes that can withstand being used to scratch components?  (Read 4661 times)

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Offline thomTopic starter

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Howdy everyone,

I repair lightning damaged devices for a living, and part of the diagnosis process is, for example, testing a row of 30 mosfets, and each one that tests bad gets a mark scraped in it with my probe tip so I know which ones to pull. I've had dozens of different cheap old aliexpress probes over the years, some with properly hard sharp tips, most with soft tips, but they all get worn down and sharpened regularly. I am wondering if there are any sharp probes with metal hardened enough to suit this specific use case?

alternatively, if you think there is a more efficient method for efficiently marking chips as I read them without having to drop my probes and pick up a pen, I am all ears!

I've got a pomna 6431 set coming with the hopes that the SS tips are higher quality than the chinesium I am used to
 

Online bdunham7

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The Probemaster gold-plated SS probes are really sharp.  They'll stab you quite easily and they come with little safety covers on them to keep them from poking through their packaging.  I can't say how long they will stay that sharp being used as you state, but mine are still dangerously sharp after years of normal use.

https://probemaster.com/8000-series-test-leads-only/
A 3.5 digit 4.5 digit 5 digit 5.5 digit 6.5 digit 7.5 digit DMM is good enough for most people.
 
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Online joeqsmith

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I get the old dental picks and grind the ends.  Add wire and some shrink tubing.   

If you want to just buy a set, I have some stainless like these that can be sharpened as well:
https://www.pomonaelectronics.com/products/dmm-test-leads-and-probes/probe-tip-040-quad-point-pogo

Offline thomTopic starter

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Hi Joe, do you mean you have a 3rd party source for ponomoa compatible SS tips? I bought the full set, and if the SS tips are good, it would be nice to be able to buy just those instead of having to buy the 10 pc kit!

as an aside, I recognize you from youtube, your videos are fantastic, thanks for the effort you put in!
 

Offline 2N3055

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Like Bdunham7 said, just buy Probemasters.. They are very good quality, very sharp (scarry), made of stainless steel.
Pomona 6341 are expensive piece of crap. I have both and Probemaster is superior quality..
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Offline thomTopic starter

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I went with the ponoma because of the replaceable tips, I wear those down like crazy, but I'll get a set of the probe masters as well and see if they can survive the abuse, but I am currently most intrigued by joe's excellent idea of using dental picks
 

Online joeqsmith

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Sorry, I do not.  The ones I use are branded by Fluke.  Many people do not like the quality and fine leads.   For surface mount, I like them.   

https://www.fluke.com/en-us/product/accessories/test-leads/fluke-tp912

One work around may possibly be sewing needles.  I often use them to make custom probes.   They are very inexpensive and have several sizes available.  You may find some with the proper OD that you could just snap off and use with existing probes.   You can also solder to some of them. 

Link showing a typical use of sewing needles:
https://www.eevblog.com/forum/testgear/sub-$1000-vna-for-antenna-matching/msg4551707/#msg4551707

Online joeqsmith

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I suspect that the picks that are sold at flee markets are not the quality of steel you will find at the dental office.  It wouldn't hurt to ask your dentist the next time you are in for a visit.   

Online joeqsmith

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I've wondered about using a Tungsten electrode for welding but have never tried it.  The rods have a smaller diameter than the dental picks. 

Offline Fungus

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Do you also knock screws in with a hammer?

Buy a proper sheet metal scribe and use that. You can probably tape a wire to one and use it as a probe. :)

(or just accept that you're going to need to get new probes every month because you're lazy...)

« Last Edit: December 15, 2022, 05:16:07 pm by Fungus »
 
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Offline thomTopic starter

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looks like the pomona probes have 1.02mm tips, which could probably socket 1.0mm electrodes. I'm going to see if any of my local joints have any in stock I can try fitting in them, but I think you might have properly solved my problem. while the probe masters are sturdier, looks like they accept 1.36mm tips, which I doubt are going to be easy to find a tungsten mate for.

https://sunstonewelders.com/orion-micro-tig-welding-electrodes

I've gone the sewing needle route before, and find that the tips break off very fast if used for scraping, to say nothing of how frequently they draw blood.
 

Online joeqsmith

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looks like the pomona probes have 1.02mm tips, which could probably socket 1.0mm electrodes. I'm going to see if any of my local joints have any in stock I can try fitting in them, but I think you might have properly solved my problem. while the probe masters are sturdier, looks like they accept 1.36mm tips, which I doubt are going to be easy to find a tungsten mate for.

https://sunstonewelders.com/orion-micro-tig-welding-electrodes

I've gone the sewing needle route before, and find that the tips break off very fast if used for scraping, to say nothing of how frequently they draw blood.

I'm interested in hearing how it works out.   Maybe invest in a soft wheel to sharpen them if you don't already own one.

***
Forgot, attached is a sheet metal scribe for Fungus.  Note the predrilled hole to attach your test lead wire to.  Also when one tip starts to dull, you just rotate to the next.  Many benefits. 
« Last Edit: December 15, 2022, 05:25:58 pm by joeqsmith »
 

Offline Fungus

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Forgot, attached is a sheet metal scribe for Fungus.

Maybe they have a different name in your country.

I was thinking more of this: https://www.aliexpress.com/item/4000257756923.html

 

Online joeqsmith

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Maybe they have a different name in your country.

Most people realize smart ass posts get smart ass responses but maybe its different in your country. 

Offline james_s

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Sounds like what you need is a scratch awl, or just use a permanent marker, that's what I do.
 

Online tautech

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Sounds like what you need is a scratch awl, or just use a permanent marker, that's what I do.
Makes more sense to buy a pack of these if needing to place an obvious mark on so many fried components:
https://www.ebay.com/b/Sharpie-Pens-Markers-for-Artists/28109/bn_56922649

One can easy spend more on a set of good DMM leads than a 6 pack of white markers.
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Offline thomTopic starter

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I will explain this to clear up any confusion about my situation. I literally mark upwards of 1000 of these components a day, 6 days a week. with how I do it, a component tests bad, I scratch it with the probe already in my hand, and test the next component.

if I were to use a sharpie, for example, I would have to put down both probes, pick up the sharpie, take off the lid, mark the component (make sure it's the right one becasuse now I had to take my eyes out of my microscope), put the cap back on, pick up my probes, go back to the scope and carry on.

if you could do that all in 3 seconds, it would add about 50 minutes to my average work day.

don't mistake laziness for efficiency.

anyhow, I'm going to try this tungstun bit approach, but if that doesn't work, making a probe out of a tungsten awl is an excellent back up plan

 
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Offline Bud

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Gee..., you guys have that many lightnings in your location?
I' think a pair of machinist scribes with cold welded to them multimeter wire leads would set you for long time.
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Offline floobydust

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Pomona 6341 I dislike because they have an aluminium tube for the probe sheath and the dissimilar metals sucked for contact resistance and it's soft.
OP when you get yours, please check if this has changed as I complained to Pomona.
Their gold plated probes don't have this problem but are spring-loaded.

Best I've used is Huntron Tracker MP20 or MP10 I can't remember but I thought they are tungsten and telescoping.

For poking through conformal coatings, I have best luck using SS dental picks with an attached test lead.
Another approach is making your own probe using sewing needles and old ball point pens. I've done that on the cheap.
 

Offline thomTopic starter

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they should be here on monday, if you have any specific thing you would like me to do to test them, let me know! if the socket is in fact soft aluminum, I have a feeling no matter what tips I use, I'm going to wear it out fast just from the way I use these things, but we will see.

I've never even heard of those huntron probes, I'll add those to the list I'll try if these pomona don't live up
 

Offline DC1MC

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Offline notsob

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You could try acupuncture needles - I've seen home made test leads using them
 

Offline james_s

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What on earth are you doing that has 1,000 bad components a day? At that volume it seems like it would be worth automating the process, unless it's all different types of devices being tested. I knew a guy that worked at a company that made automated flying probe test machines that could do that sort of thing.
 
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Offline thm_w

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What on earth are you doing that has 1,000 bad components a day? At that volume it seems like it would be worth automating the process, unless it's all different types of devices being tested. I knew a guy that worked at a company that made automated flying probe test machines that could do that sort of thing.

Yeah getting mixed messages here.
Also FETs are often ground or Vcc referenced, so you can often clip one lead onto ground, then test with the other.
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Online tautech

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What on earth are you doing that has 1,000 bad components a day? At that volume it seems like it would be worth automating the process, unless it's all different types of devices being tested. I knew a guy that worked at a company that made automated flying probe test machines that could do that sort of thing.

Yeah getting mixed messages here.
Also FETs are often ground or Vcc referenced, so you can often clip one lead onto ground, then test with the other.
Yep, switched on ones (excuse pun) would have one lead with a grabber to free one hand.
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