FLUKE TL2X4W PTII 4W test lead for 8845A/8846A - Manufacturing secrets

[Kiriakos GR]

TL2X4W-PTII  (2mm tips /  1 meter cable length)  (January 2007)
TL2X4W-PT7  (2mm tips / 2.13 meter (7-foot) cable length
TL2X4W-TWZ  tweezers  (April 2008)

All were discontinued by FLUKE at 5/2023.
We are now three years later, and 5/2026 this is not far.
What comes is the memory of death day = that is the opposite of birthday.

Long story in sort, what made these TL2X4W to be considered as so special?
 
I have gathered a few facts speaking of manufacturing details.
1) They are work of Pomona, and all three they has be recorded as of American origin.
2) They use gold plated 2mm tips = American Gold
3) They use RG-316 coaxial cable, this be silver plated
4) They use the patented double banana plug this having four contacts, and I assume a bit of American Gold over them tool.

The sum is a mix of golden plated and silver plated copper.
TL2X4W-PTII this is a part code of the past.
But Pomona this keeps alive this product design, by the offering of two double banana at the end = an totally compatible product with every 4W bench top DMM.
While availability this is not a problem, it retail price this is a major problem. 


For some time, I thought that such special leads, they might be of help of some one interested to measure SMD resistor shunts all day long.
And or for old fashion current shunt inspection.

Gentlemen I am somewhat confused, of what might be the though of these brands, at setting an price that no one accepts to pay.
Manufacturing cost =  2m long RG-316 along 5$ USD for everything else, this cannot justify an 180 EUR as retail price, at least on this planet.   

[overvolt]

What is micro Ohm (u Ohm) resolution of 8846A ?

[Kiriakos GR]

The last digit this represents the quantity of 10 micro Ohm. 

0.00001

0.00010 = 100 micro Ohm

0.00100 = 1000 micro Ohm (uΩ)

At 10 Ohms lowest range. 

[Kiriakos GR]

Its time to find out the truth. 

Kiriakos made a gift to Kiriakos, for his upcoming birthday 10 of May.

A pair of TL2X4W-PTII this is on the way to Greece with SpeedPAK regular speed.
The journey begins today from Hong Kong.

TL2X4W-PTII bulk version this does not give you much options for unboxing.   
Product design of FLUKE Calibration
Country of Origin United States.
Fluke 2826215 , weight 131 grams (according to DHL shipped weight).

Anyway, I did set under my microscope any particle of information that I got due the photographs from my seller. 

Enjoy the photographs gallery for now.
 

[Kiriakos GR]

Just for fun I did also check TL2X4W-PTII  product revision history.

And I found three revisions.
First at 2006, black wires and a banana plug with shape of pyramid.
Second at 2007, black wires and new redesigned banana plug  (TL2X4W-PT  = 70 VDC Max).

Third at 2008, crystal clear wires, and again with the recently redesigned banana plug.
500 mA  / 1000 VDC
Plus engraved text .. with product model 
Since 2008, this final product, it was in production up to 2021.

Never touched before Pomona Electronics gold, but it will happen soon.   

[overvolt]

Kiriakos made a gift to Kiriakos, for his upcoming birthday 10 of May.

You are a little devil after all 
I bet that eyes from Everett, WA, they do visit frequently this Blog. 

Congratulations for been able to find this rarity down to Honk Kong, and at a friendly price. 
Your 8846A will be very happy !
Plus your self will have another one educational journey at 4W Low Ohm resistance measurements, and a pack of fresh experiences.

True knowledge never comes for free. 

[Kiriakos GR]

The guys at Everett, WA,  they skipped to offer an storage solution for TL2X4W-PTII 

Either way, I did find a local source, to add in my list of possible choices. (3.5 EUR)
https://grobotronics.com/storage-box-plastic-with-foam-black-230x180x45mm.html

Thanks mate 

[Kiriakos GR]

Now lets make a first dive, at TL2X4W PTII actual electrical performance.

First customer feedback: robrenz on Feb 15, 2014 / tequipment.net
These probes only work with the fluke 8808A, 8845A and 8846A meters with the split jacks.
They are nicely constructed and work well.
They are kelvin connected meaning there is separate source and sense wires all the way except for the last bit of tip that sticks out of the probe body.
The combined resistance of that last solid part of both probe tips is about 400 to 500 micro Ohms.
This can be removed by using the relative function with the probe tips touching to null out that residual resistance.
Overall very nice to use with the single shielded 2 conductor cable per probe.
Test performed at 8846A

Second customer feedback: This is for TL2X4W-PT older with black wires.
Year 2024 at Australian Blog, one user measured and reported  520 micro Ohms. 
0.00052 Ω
Test performed at 8846A

Third customer feedback:  This will be Made in Greece.
I was never expect that this pair of tests leads this would be so extremely unpopular.
Entire internet this is empty of clues.
And about FLUKE offered product documentation, this is another bad joke.

TL2X4W-PTII manufacturing details
Probe body incorporates a two step mold process.
First step is Polypropylene for probe rigidity.
Second step is color gray Santoprene rubber for handling comfort, added insulation protection and wire strain relief.
(source: Pomona Electronics Copyright © 2012  /  5519A  test leads PDF)

Santoprene = Thermoplastic elastomer (TPE).

[Kiriakos GR]

Now lets make a second dive, at TL2X4W PTII and of what actually this is.

This item represents the class of Kelvin Test and Kelvin Pins.
The strong point of Kelvin Pins this is measuring resistive components tolerances.
And or verifying at a small resistor it actual tolerance.
For example at one 10 mOhm shunt resistor, measurement tolerances have narrowed to the micro-ohm (µΩ) range.   

And the 8846A, this indeed have the necessary display resolution so to present such measuring detail.
This Kelvin Pins rabbit hole, it goes even deeper, and down to IC packages inspection, surface mount soldering.

Fluke added much thought at the product design of 8845A/8846A, but they did leave outside the concept of automated comparator function.
Indeed by using an TL2X4W PTII, you do become fully capable to measure tolerances.
But its unavoidable of using a digital calculator, so to calculate tolerances percentage. 

Since the moment that there is not any other bench-top DMM out there, this including an automated comparator function about automated percentage calculation, then there is no room for me so to complain.   

Pass / Fail, comparator, this is another way of detecting if you are within tolerances preset.
But you do not know of how much off you are, when the measurement this is out of upper and lower limits boundaries.
Percentage calculation this it should be performed again manually.

[Kiriakos GR]

Here comes a third dive in to ultimate knowledge, this is the combination of all details that FLUKE leaved as undocumented. 

The TL2X4W-PTII leads utilize a shielded cable construction.
This shielding protects the measurement signal from environmental interference in two distinct ways:

1. AC Voltage (ACV) and High-Frequency Noise
This is where the shielding does the heavy lifting.
In ACV measurements, especially at millivolt (mV) levels:

Capacitive Coupling Rejection: The shield shunts stray electric fields (like those from nearby fluorescent lights or power supplies) to ground before they can induce a voltage on the center conductor.

Logistical Edge: Unlike standard unshielded leads which act as antennas for 50/60 Hz hum, the shielded TL2X4W-PTII provides a cleaner signal path for precision low-level AC.

2. DC Voltage (DCV) and Low-Frequency Noise
For a 10V DC reference, the "noise immunity" shifts from blocking interference to managing thermal stability:

Thermal EMF (Seebeck Effect): At the mV and µV levels in DC, the primary "noise" is actually parasitic voltage generated by temperature differences across dissimilar metals.
The gold-plated Copper-Beryllium (CuBe) tips of the TL2X4W-PTII are designed to minimize this thermal EMF.

Triboelectric Rejection: Because the conductors are contained within a stable, shielded jacket, they are less prone to generating "motion noise" (triboelectric effect) compared to loose, swaying standard leads.


Summary of Benefits   
Measurement Type          Primary Benefit of TL2X4W-PTII

ACV (mV)        Shielding rejects EMI/RFI and power line hum (50/60 Hz).
DCV (Ref)        Low thermal EMF junctions and high-quality gold plating ensure stability.
Resistance       True Kelvin 4-wire cancellation of lead resistance.

In short, while the shielding is technically an "AC benefit," the high-end material choice (gold-on-CuBe) makes them superior for ultra-stable DC as well.

Damn ... I have now to toss away the nickel plated bananas over my voltage reference. 

[Kiriakos GR]

So far I was speculate that TL2X4W PTII, this does not have any competitor.
I was wrong,  Keithley Instruments, Inc. , this is also a shopper of identical test leads from Taiwan. 

At of 2016, they added this product code at their accessory list.
Model 5808 Single-Pin Kelvin Probes
https://www.tek.com/en/default-accessory-series-manual/model-5808-single-pin-kelvin-probes-instruction-sheet

These are low volt 60VDC, 5A max.

[Kiriakos GR]

And the historical journey ends by a very rare find. 

Pomona Electronics 6303 and or TL2X4W-PT  Rev 1.0    (23 years ago)
RG-174/U
They begin by using naked bananas.
They have engraved company logo.
This product design was sort lived, as it was also and the FLUKE TL2X4W-PT.
 

And therefore FLUKE TL2X4W PTII as we know it, this it can be considered with out doubt as fourth revision.