Fluke A55 Connector

Started by Hawaii596, 06-22-2016 -- 10:33:35

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Hawaii596

06-22-2016 -- 10:33:35
If anyone has or uses Fluke A55 Thermal Voltage Converters (TVC's), you'll know what I'm talking about.  I have a recently recommissioned A55-3V that Fluke primary lab calibrated for me for part of my setup being put together for calibrating Fluke 5790A's (wideband flatness check).

I did NOT realize how hard to find (or even correctly identify) these connectors are. They are, per my information, an Amphenol 80-PC2M (2 offset male pins on the output connector).  And it matches up with an 80-PC2F1.  I don't quite get why you can somewhat find the 80-PC2M connectors (the one on the A55), but the one that mates to it (80-PC2M) is pretty much nowhere to be found.

There are two pin connectors galore, but without the offset (pins are not centered).  Non-offset versions are available for a few dollars.

I found one cable on ebay that is certainly an A55 output cable assembly (just not labeled that way; the seller may not know what it goes to).

Anyone have any part numbers currently available for this?
"I often say that when you can measure what you are speaking about, and express it in numbers, you know something about it; but when you cannot measure it, when you cannot express it in numbers, your knowledge is of a meagre and unsatisfactory kind."
Lord Kelvin (1824-1907)
from lecture to the Institute of Civil Engineers, 3 May 1883

BamaKid

#1
06-22-2016 -- 11:47:20
I asked my Primary Standards Metrologist and he provided this information:

The A55 used old microphone connectors. I think the needed part to mate with the A55 is the 80-MC2F, which is the inline cable mount rather than the panel mount.

Available from either of the two websites shown below (which we do not have direct experience with):


https://www.kenselectronics.com/lists/micplug.htm

http://www.electronicplus.com/content/ProductPage.asp?maincat=aco&subcat=am2

Hawaii596

#2
06-22-2016 -- 12:45:44
From what I can tell, there is an 80-MC2F and an 80-MC2F1.  the 80-MC2F has male threads on the outside perimeter with 2 female jacks, and the 80-MC2F1 has the 2 female jacks, and a female threaded collar that screws down onto the male outer threads on the A55.  Very confusing.  I did see the second link with the item for $37.50.  I may yet buy that one.  I just ordered the already made used cable assembly with the 80-PC2F1 on one end, and double banana on the other end.

I am pretty sure in the dozens of sites I searched, that I found the other site as well.  What has been confusing is that there are tons of 2 pin mic connectors.  But apparently, pretty much all of them except the 80-PC2F1, and related 80 series do not have the offset of the two pins.  I read one article that a lot of ham radio operators used to have these connectors, and retrofitted their equipment with non-offset connectors (extremely common), as the 80-PC2F1 is nearly impossible to find.  I am halfway thinking of buying some common non-offset connectors and retrofit my A55's.  I only have two A55's, both of the 3 volt variety.  Most of my TVC's are either the HP with two little terminals, and a few Ballantince with the 3 pin amphenol plugs (I will need to build some cables for them as well).

Thanks for the inputs.
"I often say that when you can measure what you are speaking about, and express it in numbers, you know something about it; but when you cannot measure it, when you cannot express it in numbers, your knowledge is of a meagre and unsatisfactory kind."
Lord Kelvin (1824-1907)
from lecture to the Institute of Civil Engineers, 3 May 1883

N79

#3
06-23-2016 -- 17:32:21
Yeah, every time we get a set of A55s in the lab (which is rare) I have to scrounge around and find our cables assemblies for those connectors. You may save some headache in the future if you go ahead and change out the connector to something more universal, such as the 3-pin connector Ballantine typically uses (I can't remember the model).

Hawaii596

#4
06-24-2016 -- 09:24:56
I know that connector.  We don't get other people's A55s in, but we own two of the 3V flavor.  Do you know if the Ballantine connector definitely fits (have you done this).  If so, I like that.  You could even use the third pin to attach a GUARD.  I like it.  I will be thinking about this.  I am actually in TVC maintenance mode right now.  And I have a few Ballantines that I normally have to use Pomona pin adapters for, and planning to buy/build cables for.  But if this could work to retrofit the A55 - I like it.  Thank you.
"I often say that when you can measure what you are speaking about, and express it in numbers, you know something about it; but when you cannot measure it, when you cannot express it in numbers, your knowledge is of a meagre and unsatisfactory kind."
Lord Kelvin (1824-1907)
from lecture to the Institute of Civil Engineers, 3 May 1883

N79

#5
06-26-2016 -- 01:11:12
Unfortunately I don't think it would be an easy job to switch out connectors. I was thinking more on the lines of placing the internals of the A55 into a new can with more adaptable connectors, but maybe it would be more trouble than it's worth. Ballantine still sells great cans, even ones with a built-in tee. Otherwise, in a pinch, you can use little croc clips or tiny barrel conductors to connect to the pins. I've used both the proper connector and clips and as long as the environment is stable and you have good contacts there should be no discernible difference in the readings.

Hawaii596

#6
06-29-2016 -- 10:49:49
In all likelihood, I won't do anything to mine.  We have one primary 3V unit that we send to Fluke, and will only use it to calibrate a few items in the standards lab.  I just received my nice used cable from ebay; and it works nicely.  What was also nice was that when we just recently sent it out to Fluke, they retrofitted it with a BNC, and removed the old GR-874, with GR-874 to BNC adapter.
"I often say that when you can measure what you are speaking about, and express it in numbers, you know something about it; but when you cannot measure it, when you cannot express it in numbers, your knowledge is of a meagre and unsatisfactory kind."
Lord Kelvin (1824-1907)
from lecture to the Institute of Civil Engineers, 3 May 1883
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