Probe Master Test Leads (Partly Dissected)

[FRR]

I wanted to give Probe Master a try and ordered through eBay since it was a 2 click checkout. The seller mailed me a set of defective leads where the red probe wouldn't fit into any of my gear due the inner diameter of the shroud being too small.



I received a refund, but that doesn't solve my problem of wanting to try Probe Master test leads. So I did what anyone would do and took it apart....



The two inject molded pieces are glued together which didn't take long to take apart carefully. Inside we have the strain relief and silicone wire soldered directly to the banana plug. One minute with a 3 flute end mill and I was ready to reassemble. A few drops of cyanoacrylate glue and I was done.




I hope this was useful for someone.


Full list of pictures can be seen here: https://imgur.com/a/4gy3YVa

[commongrounder]

Interesting.  I also bought two sets of these probes on eBay, probably from the same seller, and had an issue with one of the red plugs fitting very snugly in my meter (the other red plug was clearly different).  It didn’t seem bad enough in my case to ask for a refund/exchange. Now that I’ve seen it done, I’ll have to try this modification. 

[bson]

The shrouds on my PM leads clearly say "Probe Master" in raised letters.  Are you sure you bought the real deal?

Edit: adding an image of the modular straight jacks I have, bought directly from their website.

[commongrounder]

My probes have “Probe Master” clearly molded into the handles. Also, the right angle plugs have “PM” molded into the cap (not in view in FRRs posted pictures). I believe my batch of probes was made for the military, and were probably obtained as surplus. They are definitely “Softies”, but have a different model number than the commercially available ones.  I really like them. A step above the Fluke type probes.  They have much lower lead resistance, too. My theory about the fit is there must have been batches of the shrouds that were made with different plastic formulas. Looking at the two red and two black plugs, I can see that just the one (tight) red one looks and feels a bit different. Anyway, they were a great deal, and I’m happy with the purchase.

[FRR]

Interesting.  I also bought two sets of these probes on eBay, probably from the same seller, and had an issue with one of the red plugs fitting very snugly in my meter (the other red plug was clearly different).  It didn’t seem bad enough in my case to ask for a refund/exchange. Now that I’ve seen it done, I’ll have to try this modification. 

Sad to hear I wasn't the only one. Mine was bad enough to where it literally wouldn't fit into my gear. I tested on 2 different model Keithley units, 2 HP/Agilent, and 6 Fluke meters. If you are going to try this and use a drill bit instead of an end mill make sure to be careful to not go too far since there is a lip inside holding the banana plug in place.

[FRR]

The shrouds on my PM leads clearly say "Probe Master" in raised letters.  Are you sure you bought the real deal?

Edit: adding an image of the modular straight jacks I have, bought directly from their website.

<picture removed>

I actually contacted PM about this and they confirmed they had a bad batch some time ago, but weren't sure how they were still around. I went ahead and ordered a set directly from PM and will confirm if they are authentic, but they certainly look the same with Probe Master written on the handle and the letters PM on the banana plugs.

[FRR]

I received a set of probes directly from Probe Master. The eBay set definitely aren't fake / a knockoff, but they aren't 100% identical either. It seems like the eBay units are an older run as they have made some progress with the current probes.



The molding, sizing, materials, ect are all the same. The new probes vinyl strain relief pieces are quite a bit more flexible now. I don't know if this is due to an aging effect or a new formula. The gold plated contacts are now polished. Passes the fingernail test. The banana plug end tip is flat where it was rounded before. I measured the resistance of each lead using a 4 wire setup and they all measured the same.

The only thing I would say I am bit disappointed with is that the red lead is about 3/4in longer than the black one.






Overall I would say its worth the extra minute it takes it purchase directly since the probes do seem a bit nicer now.

[tooki]

The shrouds on my PM leads clearly say "Probe Master" in raised letters.  Are you sure you bought the real deal?

Edit: adding an image of the modular straight jacks I have, bought directly from their website.

<picture removed>

I actually contacted PM about this and they confirmed they had a bad batch some time ago, but weren't sure how they were still around. I went ahead and ordered a set directly from PM and will confirm if they are authentic, but they certainly look the same with Probe Master written on the handle and the letters PM on the banana plugs.

I also recall them at one point years ago mentioning something like a “better fit with Fluke” shrouded banana plug option. So my hunch is that they had an earlier design that was different from the current one — and that the eBay seller is getting rid of that ancient version.

Bear in mind, Probe Master has been selling these probes since the late 80s, I think. So it’s entirely plausible IMHO for older samples to have lost suppleness in the squishy probe body.