Author Topic: Old DMMs  (Read 6474 times)

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Offline TraderTopic starter

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Old DMMs
« on: May 04, 2021, 01:04:15 am »
I wonder what are the first handheld DMMs with most of the functions of modern DMMs, like Capacitance (and maybe Frequency counter).

HP 974A - no capacitance
Fluke 80xx, 77 - no capacitance

 

Offline TraderTopic starter

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Re: Old DMMs
« Reply #1 on: May 04, 2021, 01:13:05 am »
HP 972A / 973A - has capacitance  (first one from HP?)
Tektronix?
« Last Edit: May 04, 2021, 01:15:37 am by Trader »
 

Offline wizard69

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Re: Old DMMs
« Reply #2 on: May 04, 2021, 04:36:00 am »
I wonder what are the first handheld DMMs with most of the functions of modern DMMs, like Capacitance (and maybe Frequency counter).

HP 974A - no capacitance
Fluke 80xx, 77 - no capacitance

why do you consider capacitance a feature of modern DMM's?    It seems like a very arbitrary way to categorize multimeters.    For instance some consider temperature measurement mandatory but that has never been the primary domain of multimeters.   In both cases there are better instruments available for both temperature and capacitance measurements.

I know I'm an old guy that started out with little but man I would have died growing up just to have a volt meter much less a multimeter.
 
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Online BeBuLamar

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Re: Old DMMs
« Reply #3 on: May 04, 2021, 01:51:30 pm »
Fluke 87 which was introduced in 1988 or so has capacitance.
 
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Offline TraderTopic starter

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Re: Old DMMs
« Reply #4 on: May 04, 2021, 02:39:27 pm »
why do you consider capacitance a feature of modern DMM's?    It seems like a very arbitrary way to categorize multimeters.    For instance some consider temperature measurement mandatory but that has never been the primary domain of multimeters.   In both cases there are better instruments available for both temperature and capacitance measurements.

I realized that most of the features from a modern DMM are present in the old DMMs, but not the Capacitance.

I consider measuring Capacitance more relevant in electronics development and maintenance than temperature, but ok.
 

Offline gdewitte

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Re: Old DMMs
« Reply #5 on: May 04, 2021, 02:55:12 pm »
May not be the oldest, but the Heathkit IM-2320 has capacitance and hFE.  :-+
 
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Offline Fungus

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Re: Old DMMs
« Reply #6 on: May 04, 2021, 03:18:15 pm »
I realized that most of the features from a modern DMM are present in the old DMMs, but not the Capacitance.

I'm guessing you never heard of the "kick test". It's how people used to measure capacitance with old analog meters.

It also works with digital meters that have an analog bar graph, eg. My Fluke 27 doesn't have capacitance on the dial but the manual has a procedure/tables for using it to measure capacitance.

 

Offline TraderTopic starter

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Re: Old DMMs
« Reply #7 on: May 04, 2021, 05:37:54 pm »
I'm guessing you never heard of the "kick test". It's how people used to measure capacitance with old analog meters.

I know this test, thank you for remind it.  But I'm talking about Capacitance Measurement, this test doesn't "measure capacitance" only check if the capacitor seems to be working.
 

Offline Fungus

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Re: Old DMMs
« Reply #8 on: May 04, 2021, 06:16:45 pm »
I'm guessing you never heard of the "kick test". It's how people used to measure capacitance with old analog meters.

I know this test, thank you for remind it.  But I'm talking about Capacitance Measurement, this test doesn't "measure capacitance" only check if the capacitor seems to be working.

OK, but I wouldn't draw the line of "Modern DMM" at the point where capacitance appeared. It seems a bit arbitrary. How about when they started using microprocessors and doing autoranging? That seems like a bigger leap to me.

Also: Are we including bench DMMs or only handhelds?
 

Offline TraderTopic starter

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Re: Old DMMs
« Reply #9 on: May 04, 2021, 08:13:33 pm »
I'm guessing you never heard of the "kick test". It's how people used to measure capacitance with old analog meters.

I know this test, thank you for remind it.  But I'm talking about Capacitance Measurement, this test doesn't "measure capacitance" only check if the capacitor seems to be working.

OK, but I wouldn't draw the line of "Modern DMM" at the point where capacitance appeared. It seems a bit arbitrary. How about when they started using microprocessors and doing autoranging? That seems like a bigger leap to me.

Also: Are we including bench DMMs or only handhelds?

"Only handhelds".   Maybe I didn't express it correctly, but my curiosity is: when a Handheld DMM was 'capable' to do All or the Majority of the measures of today's meters.

I think one of the last features implemented was the Capacitance measuring, maybe the HP 973A was the first handheld DMM with all the most important measures we see today.

http://literature.cdn.keysight.com/litweb/pdf/5967-6368EN.pdf

https://doc.xdevs.com/doc/HP_Agilent_Keysight/HP%20972A,%20973A%20Instruction.pdf
 

Offline J-R

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Re: Old DMMs
« Reply #10 on: May 04, 2021, 08:17:42 pm »
Even on modern handheld DMMs I would propose capacitance and frequency measurement functionality is somewhat over-rated. 

To properly measure a capacitor you need to be able to set the frequency.  Furthermore what you really want is to be able to TEST the capacitor so now you want an ESR meter (or an LCR meter with that feature).

For frequency measurements most DMMs top out in the hundreds of kHz and have very limited resolution, maybe 3-4 digits.  You also have no idea what the waveform looks like and it is trivial to fool them into displaying a garbage result, such as 0. So even one of the toy scopes will be better in that regard and for any amount of accuracy you will want a frequency counter.
 

Offline mansaxel

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Re: Old DMMs
« Reply #11 on: May 05, 2021, 04:34:01 am »
I would side with the posters stating that capacitance and frequency aren't such game changers as sales persons would have you believe. I think that the 8020 is the handheld DMM that set the standard for what a handheld DMM should be, and the change in performance, at sensible price point, offered by that meter is the interesting point in the DMM evolution. The rest is just incremental.

I divide my DMM hours between a Gossen MetraHit 25, a -hp- 974A and a Fluke 8060. But I won't measure capacitance with either. That's the job of the DE-5000 (repairing gear means looking at caps in several ways; first as consumables, second in terms of ESR et c.). And for frequency, one has to go benchtop. For starters it is probably hard to properly design a Cat III meter with a reference input, and a frequency counter that won't take 10MHz ref in, is hopelessly left behind.

/Måns, has not really gathered courage to test capacitors the old way, using the mains and an analog VOM...

Offline Martian Tech

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Re: Old DMMs
« Reply #12 on: May 05, 2021, 04:58:38 am »
Since this thread has already pretty much gone off the rails, I'll mention the Wavetek Meterman 27XT.  Although not the first to provide "modern" functions, it does have some interesting functionality: capacitance, inductance, logic levels.  But wait, there's more! It measures frequency up to 20MHz.  Unfortunately, it's only a 3.5 digit meter.  But I just checked mine with a 10MHz OCXO and it reads 10.00/10.01.  Not bad for a 20 year-old handheld meter that's never been calibrated since I bought it  :)
 
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Online Performa01

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Re: Old DMMs
« Reply #13 on: May 05, 2021, 07:23:11 am »
METEX 3630/50 (3.5 digits) and METEX 4630/50 (4.5 digits, 0.05 %) have been available in the 80s of last century already.

The "30" version had capacitance measurement (2 nF to 20 µF) and the "50" version had frequency measurement (specified to 200 kHz, but actually worked up to a couple MHz) on top.

These were good meters and still sold some 20 years later under various different brand names. No autoranging and no RMS measurement though.

These meters also have a feature that you won't find in modern DMMs, let alone bench multimeters: a very low input current of just a few pA. Together with the 10 Mohms input impedance, this makes for a very useable pA-meter.

 
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Offline Muttley Snickers

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Re: Old DMMs
« Reply #14 on: May 05, 2021, 07:43:19 am »
They also had logic, min/max and a pc interface as well which were some of the reasons I bought one back in 1992.   :-DMM

https://www.eevblog.com/forum/testgear/is-metex-a-quality-brand/?action=dlattach;attach=288856;image
 
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Offline HKJ

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Re: Old DMMs
« Reply #15 on: May 05, 2021, 07:52:09 am »
These meters also have a feature that you won't find in modern DMMs, let alone bench multimeters: a very low input current of just a few pA. Together with the 10 Mohms input impedance, this makes for a very useable pA-meter.

A very high input impedance is present on both handheld and bench DMM's today. On bench meter you can usually switch between 10Mohm and high, on handheld meters it is often always present in the mV DC range (On some high end meters it is switchable).
 
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Online Performa01

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Re: Old DMMs
« Reply #16 on: May 05, 2021, 12:25:30 pm »
These meters also have a feature that you won't find in modern DMMs, let alone bench multimeters: a very low input current of just a few pA. Together with the 10 Mohms input impedance, this makes for a very useable pA-meter.
A very high input impedance is present on both handheld and bench DMM's today. On bench meter you can usually switch between 10Mohm and high, on handheld meters it is often always present in the mV DC range (On some high end meters it is switchable).
I'm not sure what you want to express with that?

I was not talking about input impedance, but input (bias) current. And this doesn't change, whether you have some 10 meg resistor across the input or not.
If I claim that no bench DMM comes even close to the old Metex 4650, you may expect that I have measured dozens of them, from venerable Schlumberger 7150 plus up to Keithley 2001. The best of them have a bias current of some 30 pA, but none of them comes close to <5 pA like the old METEX does.

Input bias current is especially bad on the meters with alleged high input impedance, like >10 Gohm for most bench DMMs in the low voltage ranges.
And this is the trap for youngplayers: you might think you can use such a DMM like an electrometer (for low voltages at least), but that's not the case, not by a long shot.

I also have checked several more modern handhelds. The "high impedance range", if present, often is only some 1 Gohm, but the really important thing is the (more or less constant) input bias current anyway. None of the more modern DMMs I've come across so far had nearly as low a bias current that it would be able to compete.

 
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Online Performa01

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Re: Old DMMs
« Reply #17 on: May 05, 2021, 12:28:57 pm »
They also had logic, min/max and a pc interface as well which were some of the reasons I bought one back in 1992.   :-DMM

https://www.eevblog.com/forum/testgear/is-metex-a-quality-brand/?action=dlattach;attach=288856;image
Yes, but that's the "CR" variant, which was only available in the late 80s or even early 90s.
The venerable 4650 (without CR) did not have the bar graph, no min/max and no PC interface.
 

Offline TraderTopic starter

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Re: Old DMMs
« Reply #18 on: May 05, 2021, 03:05:07 pm »
Very nice to know about these very good "first DMMs", I never heard before, thanks for sharing.

Capacitance could be not so important to some people but is very handy for a quick test. But if you really want properly check the capacitor, you not only need a scope and awg, but also submit it to the Max Voltage (at least 90%) to certify if all specs still fine; this requires a much more specialized (and expensive) tester.

Other important features from today's high-end DMMs are: TRUE-RMS with an AC bandwidth of at least 20 kHz.

One of the first DMMs to implement that seems to be the:

- Yokogawa 7537 04 # https://almateks.com/doc/dmm-e-150.pdf  (page 9), and the

- HP 973A # http://literature.cdn.keysight.com/litweb/pdf/5967-6368EN.pdf (page 2)

As a plus, they have Bargraph and Dual Display.

(I can't find the released year, 1994?)
« Last Edit: May 05, 2021, 03:06:51 pm by Trader »
 
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Offline TraderTopic starter

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Re: Old DMMs
« Reply #19 on: May 05, 2021, 03:21:45 pm »
METEX 3630/50 (3.5 digits) and METEX 4630/50 (4.5 digits, 0.05 %) have been available in the 80s of last century already.

The "30" version had capacitance measurement (2 nF to 20 µF) and the "50" version had frequency measurement (specified to 200 kHz, but actually worked up to a couple MHz) on top.

These were good meters and still sold some 20 years later under various different brand names. No autoranging and no RMS measurement though.

These meters also have a feature that you won't find in modern DMMs, let alone bench multimeters: a very low input current of just a few pA. Together with the 10 Mohms input impedance, this makes for a very useable pA-meter.

Maybe the "winner"  :-DMM

METEX 3630/50 (3.5 digits)
http://archive.retro.co.za/archive/electronics/Metex%20M3600%20B%20Series%20Operating%20Manual.pdf
https://www.radiomuseum.org/r/metex_digital_multimeter_m_3630_d.html

METEX 4630/50 (4.5 digits, 0.05 %)
http://elektron.pol.lublin.pl/users/elekp/labor_instr/METEX_M-4650CR_Manual.pdf
 

Offline kleiner Rainer

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Re: Old DMMs
« Reply #20 on: May 06, 2021, 09:20:39 am »
My contender: Protek/HungChang/Voltcraft 506. MAX134-based 3 3/4 digits, true RMS, dual display, bar graph.

https://www.radiomuseum.org/r/hungchang_protek_506.html?language_id=2

Bought mine around 1995. Does capacitance (100uF max.), inductance (100H max), frequency up to 10MHz, dB, logic probe, temperature (type K), signal output (2kHz, 4kHz, 8kHz), serial interface and backlight.

Greetings,

Rainer
 
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Offline HKJ

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Re: Old DMMs
« Reply #21 on: May 06, 2021, 09:49:33 am »
Bought mine around 1995. Does capacitance (100uF max.), inductance (100H max), frequency up to 10MHz, dB, logic probe, temperature (type K), signal output (2kHz, 4kHz, 8kHz), serial interface and backlight.

Now the timeline is getting close to the Fluke 189 or 89-IV. I do not now when the 89-IV was released, but the third revision of the manual is from 1999 (The 189 was released around that time and was basically a rebrand of the 89-IV).
And that meter do not look old compare to a modern DMM:
 
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Offline Fungus

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Re: Old DMMs
« Reply #22 on: May 06, 2021, 10:05:43 am »
Bought mine around 1995. Does capacitance (100uF max.), inductance (100H max), frequency up to 10MHz, dB, logic probe, temperature (type K), signal output (2kHz, 4kHz, 8kHz), serial interface and backlight.

Now the timeline is getting close to the Fluke 189 or 89-IV. I do not now when the 89-IV was released, but the third revision of the manual is from 1999 (The 189 was released around that time and was basically a rebrand of the 89-IV).
And that meter do not look old compare to a modern DMM:

The original Fluke 87 has almost the same features as the 87V. The 87's manual is dated "August 1988".


« Last Edit: May 06, 2021, 10:09:59 am by Fungus »
 
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Offline HKJ

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Re: Old DMMs
« Reply #23 on: May 06, 2021, 10:41:22 am »
The original Fluke 87 has almost the same features as the 87V. The 87's manual is dated "August 1988".

But that meter lacks capacity and temperature.
Other features of the 187/189 was Autohold, AC+DC and computer connection
« Last Edit: May 06, 2021, 10:50:06 am by HKJ »
 

Online BeBuLamar

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Re: Old DMMs
« Reply #24 on: May 06, 2021, 11:09:51 am »
The original Fluke 87 has almost the same features as the 87V. The 87's manual is dated "August 1988".

But that meter lacks capacity and temperature.
Other features of the 187/189 was Autohold, AC+DC and computer connection

I had the original 87 around 89 or so. It doesn't have temperature but does have capacitance but only to 5 microfarad not 10 milifarad like the 87V. Although the 87 had lifetime warranty but Fluke only fixed my display problem once. The second time they said they couldn't fix it and offer me $100 toward a new meter. So I bought the 189 which was around 2005 at the time and shortly after I bought the 189 Fluke contacted me for an interview about a new DMM they were working on which became the 289 now. They had it simulated on a laptop computer so I didn't know the 2 most drawback of the 289 is the full dot matrix display contrast is so low and boot up time is too slow too. I have the 289 but I rarely use it neither do I use the 189 very much and in fact I use the 87V daily.
 
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