Does anyone know when Fluke first started making the 77?

Started by USMCPMEL, 02-10-2011 -- 09:26:51

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Hawaii596

#15
03-22-2011 -- 08:37:34
In some metrology forum years ago, I remember hearing of a company that owned thousands of Fluke 77's (can't remember who).  It was said they had more than five years of cal history on them with zero out of tolerances.  Based on that justification, they made them all NCR (No Cal Required).  Can't quite say I agree with doing that; but an interesting snapshot of how reliable the 77 is.  It is kind of the godfather of handheld DMM's --- the original FLUKE 77 (kind of makes me feel old, remembering that I was in calibration when they first came out).
"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

WestCoastCal

#16
03-22-2011 -- 09:22:16
Here's an interval analysis report with a Fluke 77 highlighted.  250 cals, 8 out of tols-very impressive.  A recommended 571 day cal interval on a spec interval of 365 days saves about 50% of cal costs (although it's a bad idea to base IA data on a make model) this example shows the incredible reliability of the the 77.

Hawaii596

#17
03-23-2011 -- 09:57:29
I think these days (based on my way too extensive experience with them) is that most of the OOT's on original model 77's is other than actual accuracy drift (if you understand my implication).  It seems most of the OOT's I've seen over the years on 77's was some wear and tear aspect, such as corrosion on the wafer rotary function switch.

Out of curiosity, do you happen to know the mechanism of the OOT's on those 8 (this is my overly analytical side wondering)?
"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

WestCoastCal

#18
03-23-2011 -- 17:42:37
We have electronic test point data going back to July 2002.  I pdf'd the report but it is at 135 k, 7 k above the forum limit, so I have attached the first page of the report.  I'll email the full report to anyone that wants it, just send me a PM.  The Instrument Summary section displays the observed and apparent reliability, EoP, Recommended Cal Interval, etc for the instrument.  The Test Point Detail section displays the info for the 1st test point, 0 mV and the as found measured values on different assets from July 2002 to December 2004.  Interval analysis is based upon as found data, not as left data; as left data is not included in the report.

Hawaii596

#19
03-24-2011 -- 11:44:32
Oddly enough, yesterday I assisted a junior tech with an OOT on a Fluke 75 (original type).  I read high in ohms at the lower test points.  My first thought was dirty wafer switch, but nope.  Turned out to be separated COM terminal that twirled around and added series resistance.  I reflowed the solder and back in tolerance.  Which continues my theory that the original Fluke 70 series don't drift out of spec.  They were made so tight (in terms of component values) that they don't drift out.  I have an old original type 77 out in my garage that every five or so years I dig out and check.  I should probably bury it in the back yard for ten years and experiment that way. 

I think about the only thing that goes wrong with them is usually oxidation/corrosion related, or if someone manages to blow one up (which I have actually seen).  I saw a tech once erroneously connect a 77 to an RF source used in an etcher (type used in semiconductors) to measure the RF signal.  You could smell what it did.

I think an occasional cleaning of the LCD elastomer, a little anti-oxide treatment on the wafer switch and occasional cleaning of the terminals, those things will still be around for decades to come.  They are a legend to me.
"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

metrologygeek

#20
03-24-2011 -- 13:53:57
But they don't make as good a wheel chock as the (also legendary) Simpson 260.

OlDave

#21
03-24-2011 -- 14:13:41
Quote from: metrologygeek on 03-24-2011 -- 13:53:57
But they don't make as good a wheel chock as the (also legendary) Simpson 260.
If you want a really GOOD wheel chock you need a good old AN/PSM-6.. They hold up much better than the flimsy plastic of the 260.

Hippie

#22
03-24-2011 -- 18:05:20
Ahh, the PSM-6. Had come into the lab, it had been runover by a truck on the flight-line. Still worked, and was in tolerance. That was at Holloman AFB back in 1983 I think.
Peace Ya'll

Hawaii596

#23
03-24-2011 -- 18:25:14
TRIPLETT 630NA - OOOH RAH !!  (I'm not a Marine, so pardon me for borrowing of the expression - I'm Navy).

I don't remember the PSM-6, we had the AN/PSM-4 though.
"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

Bryan

#24
03-24-2011 -- 20:12:41
The Simpson 260 is legendary, can you think of any other equipment that has a devoted web site?
http://www.simpson260.com/

Hawaii596

#25
03-25-2011 -- 07:52:55
And I believe I have worked on the -1, -2, -3, -4, -5, -6, -6P, -6XL, -6XLP, -6XLPM, -8, and that's the only ones I can remember.  The electricians on the ships used to bring them in by the box load (literally), about a dozen per box.  Them were the good old days (oh my gosh, I feel old saying that).

I remember the most common problem on them was when they would come in with a smokey smell, I immediately knew an electrician had forgotten and left it in ohms function, and measured 440VAC (the main grid voltage on the ships at that time).  I would open it up, and there would be this smoke trail along the sides of what used to be a solder trace on the circuit board, and at the two ends of the smoke trails, there would be the curled up remains of the trace, blown like a fuse (and I suspect had given off light like a flash bulb).  Can you tell that I am a wannabe writer?
"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

azsimps

#26
05-10-2011 -- 17:34:08
The Navy started issuing them in 1981.  They had alot of failures back then of insufficent solder on the main chip. 

Hawaii596

#27
05-12-2011 -- 11:56:52
I'm getting old and tell re-run stories a lot... but my lab out in SIMA PH (PZQ lab code) was a test be for them in about 1982 ot 83.  Hugh Lowery delivered a box of new ones and instructed us to do our worst.  Anyone know or remember him?  He was a civilian civil servant who was over all the Pacific basin calibration labs (active duty or civil service).
"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

azsimps

#28
07-07-2011 -- 17:13:39
The Navy issued them in 1982 and we had many problems with insufficent solder on the main chip causing intermittent operation. After Fluke fixed that they were good meters.

USMCPMEL

#29
07-08-2011 -- 11:39:44
Wow coming up on the 30th birthday and I still have quite a few of them coming in for calibration.
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