EEVblog Electronics Community Forum
Electronics => Projects, Designs, and Technical Stuff => Topic started by: Kiriakos-GR on April 05, 2010, 05:19:34 pm
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I have a story to share , about my findings ,
when I got an old analog Multi-meter ( an large analog Metrawatt MA-4S ) , that got it as used for Germany (ebay ) , and came with large cables, and just banana plugs in both ends .
And I had to find good probes and cables , that can take the load of 25A .
Funny enough, I had realize by searching on ebay , that the modern Multi-meter leads , cheap and expensive , they are not made to handle anything above 10A ..
Even the FLUKE ones , that was marketed in sets with extra bits .. at crazy prices ..
" Accidentally " found the mister perfect .. " Cables Set "
The UK distributor called as “ Gunson “ automotive parts ,
the manufacturer called as “ KYORITSU “ ( Japan ) ,
and the manufacturer moves the products in his chain ,
that called as “ KEW TECH “
http://www.kew-ltd.co.jp/en/products/measurement/index.html#7155A (http://www.kew-ltd.co.jp/en/products/measurement/index.html#7155A)
So everything looks to be made in Japan !! ;D
http://www.gunsontools.co.uk/item.aspx?cat=663&item=3446 (http://www.gunsontools.co.uk/item.aspx?cat=663&item=3446)
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.
(http://img691.imageshack.us/img691/3455/gunsonset77019.jpg)
1) The probes are ( CAT III 1000V – 10A ) International Safety Standard IEC 1010
2) The cables 600V 25A - nominal .
3) The two crock sets , small = 3A & large = 40A or 53C ( operating limits )
Who will ever believe , that one " Blind bag " ( No markings - no specs - no fancy labels ) ,
would hide this small treasure in it !!
The set, had a price of 27 EUR shipped , got from Germany an extra set of identical probes +10 EUR,
and I will create two sets of leads , one for the armored tank , called as MetraWatt,
and an second for my main digital multi-meter ..
Dave .. the selector does this nice clicking noise that you love ;D
(http://img28.imageshack.us/img28/8905/bbcma4sweb2.jpg)
(http://img411.imageshack.us/img411/6971/bbcma4sweb1.jpg)
(http://img411.imageshack.us/img411/7568/bbcma4sweb4.jpg)
(http://img203.imageshack.us/img203/3264/bbcma4sweb3.jpg)
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Dave .. the selector does this nice clicking noise that you love ;D
Yeah, I love the feel of those old analog multimeters!
Dave.
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Dave as you said those Germans ... they like to confuse us ;D
This meter has an function , that I can not understand ..
Its when you set the selector of the relay mark ( capacitance ) ..
Are you familiar with this mode ?
Or, if any one , can tell what it does by reading this page from the book , it would be great ..
I need an small actual translation.. of it .
Please .. :'(
(http://img215.imageshack.us/img215/9725/relayinstructions.jpg)
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Yea I bought a nice analog meter that was marked up for 56 pounds for 20 pounds at my local electrical shop, pity the ohms is not accurate but I think I can trust the rest, nice old meter and I'm quite comfortable with it
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Never seen that symbol before.
I appears to be related to the battery test mode, but how and why?
I'd guess it means that when you chose the battery test mode, it "switches on" and draws power, so maybe a warning not to leave it in that mode?
I know there are German viewers on the forum, perhaps they could translate?
Dave.
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Hello Simon .. This one its model of 80s " thats the positive part" ,
as its quite modern , and even better " ahead of many others " .
No I do not wish to brag , but mostly to say that this one was cost at that time 250DM ( German marks) ,
I comparison with the cost of living , this one in our times , it would had a street price of 300 EUR or Pounds.
Dave .. I think that I got it .. ( by reading this enlarged ) part of the book,
It just ring a bell to me . ( Ich habe studiere Deutsch .. loooong time ago )
Those Germans !! ;D
The combination of the two selectors , forces the relay to arm ... ( so there is an complete disconnection of the leads ) ... so there is nothing that you can do with them ..
The confusing part , was the part about " capacitance " and the symbol .... the proper description
are " Battery life " !!
In praxis ... on the meter scales the lowest short one , its like a common battery tester .
The confusing part , was that I was looking the other scales so to find out the reading of how much voltage are in it ..
Nop it does not work that way , I have to look only in the small scale ... and the left end of it , represents the end point , that the battery voltage had fall at 6.5V and needs replacement .
What I did, was on this mode , to disconnect the battery clip , and see what happens ...
The Needle at this mode , with full battery goes all the way right .
By disconnecting the battery , the needle started to fall slowly ( discharging for 5 seconds ) , as soon it passed the left bar end ( of the capacitance scale ) , I noticed an strong clicking sound ( relays released ) , and then the needle falls fast, to zero point in a second .
Woh ... Normally when we see the capacitance sign , our mind goes in to a capacitors tester !!
But not in this case ..
Now , if some one could help, with the translation , it could possibly verify , my practical conclusions.
The small selector , does have the capacitance sign too.
So it must work as capacitors tester ...
But , this is another story .. that I will explore later on ;D
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Some times I act like a small boy , but I like it ... ;D
Just got my cables from England ...
I got a high-res picture of them..
They are even better than I was hopping, even the crocks and cables , have electrical ratings about 1KV CAT III
The probes looks like plastic ( with some rubber touch ) but still good , and the needles haves sharp ends.
If I connect together , all the extensions , they become as 3.5 meters long .. LOL :D
http://img704.imageshack.us/img704/4537/gunsonset77019closeup.jpg (http://img704.imageshack.us/img704/4537/gunsonset77019closeup.jpg)
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I think you may be mistaking the battery symbol as a capacitor symbol?
If you look carefully, one arm is shorter than the other.....
ie battery test....
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Point well set ... and absolutely correct !!
I have lost my words right now ...( from the surprise ) , all that I can think of ,
are that you worth " a beer " , at list .. ;D
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Surprise today , got the identical probes from Germany ... They are the same , but they stamped also with the name ( chi-shing ) .. :o
Industry and market, plays nice games ...
So the probes are Chinese , and trusted by the Japanese , English and Germans ...
Ok , all those are more in numbers than me , So I guess I have to trust those probes too ;D
http://www.chi-shing.cn/en/view.asp?ClassLayer=34 (http://www.chi-shing.cn/en/view.asp?ClassLayer=34)
Every day we learn and something new , and many times or all, we have to pay the price,
there is no other way.
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One thing to be careful about brand X test leads or brand X DMM is be sure they truly live up to the specifications. Safety is a big concern if tools are used in kV environments.
It can say its CAT III 1000V – 10A capable, but who certified and tested those leads to be CAT 3?
http://ecmweb.com/mag/electric_meter_safety_measure/index.html
Old electronic measurement devices can still be accurate, but as parts age, how safe will they be if you expose them to their rated voltages, specified when the device was new?
Any DMM can be used in low voltage applications, including no name test leads. Then, you are more concerned with precision and accuracy of measurements.
But I would be very careful once you start using those tools in AC circuits, especially line voltages that can be exposed to high voltage transients.
Fluke's are expensive not just because they are accurate and precise, but because they meet a lot of safety specifications both in their internal factory ISO standards and many standards by various countries, not just the DMM but the leads you use it on.
If you are working in low voltages, a Fluke maybe overkill for most needs.
I have a story to share , about my findings ,
when I got an old analog Multi-meter ( an large analog Metrawatt MA-4S ) , that got it as used for Germany (ebay ) , and came with large cables, and just banana plugs in both ends .
And I had to find good probes and cables , that can take the load of 25A .
Funny enough, I had realize by searching on ebay , that the modern Multi-meter leads , cheap and expensive , they are not made to handle anything above 10A ..
Even the FLUKE ones , that was marketed in sets with extra bits .. at crazy prices ..
" Accidentally " found the mister perfect .. " Cables Set "
The UK distributor called as “ Gunson “ automotive parts ,
the manufacturer called as “ KYORITSU “ ( Japan ) ,
and the manufacturer moves the products in his chain ,
that called as “ KEW TECH “
http://www.kew-ltd.co.jp/en/products/measurement/index.html#7155A (http://www.kew-ltd.co.jp/en/products/measurement/index.html#7155A)
So everything looks to be made in Japan !! ;D
http://www.gunsontools.co.uk/item.aspx?cat=663&item=3446 (http://www.gunsontools.co.uk/item.aspx?cat=663&item=3446)
1) The probes are ( CAT III 1000V – 10A ) International Safety Standard IEC 1010
2) The cables 600V 25A - nominal .
3) The two crock sets , small = 3A & large = 40A or 53C ( operating limits )
Who will ever believe , that one " Blind bag " ( No markings - no specs - no fancy labels ) ,
would hide this small treasure in it !!
The set, had a price of 27 EUR shipped , got from Germany an extra set of identical probes +10 EUR,
and I will create two sets of leads , one for the armored tank , called as MetraWatt,
and an second for my main digital multi-meter ..
-
One thing to be careful about brand X test leads or brand X DMM is be sure they truly live up to the specifications. Safety is a big concern if tools are used in kV environments.
It can say its CAT III 1000V – 10A capable, but who certified and tested those leads to be CAT 3?
The same person who certified : Hirschmann - AEG - Bosch - Siemens - Philips and others .
Old electronic measurement devices can still be accurate, but as parts age, how safe will they be if you expose them to their rated voltages, specified when the device was new?
Since when , the external case ( isolation of the meter ) ever had an expiration date ?
Since when , the German tools and devices , ( who historically was the leaders in everything have to do of building tools for the manufacturers the last 60 years ) , had safety issues !!
Do you know anything about Rubin's ? and how to use them in mechanical designs ?
Does the phrase " Swiss made watch " has any value to you !!
Think again , when you do comparisons about " accurate and precise " .
The U.S. called as ( New Land ) , because its " New " , the old one ( EU ) its the place that everything had be invented.
And Greece , are the source of maths, and teacher of the "basic theory" about anything exists on our planet, and the planets around earth ( for the last 5000 years )
Any DMM can be used in low voltage applications, including no name test leads. Then, you are more concerned with precision and accuracy of measurements.
But I would be very careful once you start using those tools in AC circuits, especially line voltages that can be exposed to high voltage transients.
Fluke's are expensive not just because they are accurate and precise, but because they meet a lot of safety specifications both in their internal factory ISO standards and many standards by various countries, not just the DMM but the leads you use it on.
If you are working in low voltages, a Fluke maybe overkill for most needs.
You are chatting with an European Industrial electrician , who lives far from the countries of Europe ,
that " are or was " Leaders at the construction of Industrial grade tools , at the last 110 years.
So, because I am the final user , I have own or just operate , many of those.
The problem , never was about " the Quality" of them , but always the price.
About Fluke , in my eyes are just another one player, on the table .
The past decade , was moving on the right track , as it was offering to the technicians ,
instruments with transparent support " Service info & fix it your self " and parts .
Something that other opponents was not offer publicly .
The last decade , they look to have " change their tactics " , now they sing a new song called as " send it to Fluke " ...
This new song , are identical with all the others , boring and with no value .
I agree that the American continent , needs to have their own heroes , even as Industrial grade manufacturers , in that matter I do not argue , and I agree .
But in worldwide level , you must have the " something more" , the "something special" ,
so to gain world wide respect .
Especially if you sell , almost identical products with all the others .
And now I will brag a bit about the Metrawatt .. ;D
Have you ever see , protection relay's in a multimeter ?
LOL ..
Best regards .. my friend ..
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Kiriakos-GR, it makes it difficult to read your posts when you have so many spaces between your punctuation.
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Thanks for the tip .. :)
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Hello K,
Good to chat. I think on safety we ended up discussing most in the Multimeter thread:
https://www.eevblog.com/forum/index.php?topic=383.0
As the discussion states, there are many tools and equipment, but even for something as common as test leads, but one can't be sure it lives up to specs unless its independently tested as the thread shows and discusses. This is far more stringent in Germany and EU than the USA.
Enjoy your new DMM.
[snip]
And now I will brag a bit about the Metrawatt .. ;D
Have you ever see , protection relay's in a multimeter ?
LOL ..
Best regards .. my friend ..
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[...]
I need an small actual translation.. of it .
Please .. :'(
(http://img215.imageshack.us/img215/9725/relayinstructions.jpg)
3.1.1 Relay Reset
To reset the protection relay switch the range selector (1) to "relay symbol".
If the relay is armed, the needle moves in the last third of the scale.
If you now switch the current type selector (2) to "+", the MA4S shows you the battery voltage.
The battery voltage is too low, if it is not displayed at all or shortly flats out after reseting the relay (at the same time the relay is disarmed).
Because of that, the battery voltage display indicates the state of the relay.
If you want to repeat the relay reset in a short period of time, you have to wait 5s between each reset (charge time of the reset capacitor).
Before switching the range selector (1) back to "relay symbol", you must switch it to another position. The range selector (1) should not stay in position "relay symbol" to avoid battery drain.
If the relay inadvertly switched itself on or off due to mechanical shock, do a relay reset to resynchronize the monitoring circuit.
3.1.2 Automatic battery monitor
The electronic battery monitor triggers the relay, if the battery is low. In this case the relay reset is electronically blocked.
If the 9V battery is removed from its compartment, the relay is triggered, wehen the voltage drops under the internal reference voltage (6,5V).
After relacing the battery, the range selector (1) has to be switched in any other position (for example 750V) for 5 seconds, before initiating the relay reset.[/tt]
That's the translation to the best of my knowledge.
Although I think it seriously needs cleening up by a native english speaker. ;)
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Welcome Germany ... ;)
You saved my life ... and do not worry, I have no more pages for you. ROFL ;D
About cleaning , its got cleaned ...
And just printed it.
3.1.1 Relay Reset
To reset the protection relay circuitry, switch the range selector (1) to "relay symbol".
The relay gets active , and the needle moves in the last third of the scale.
If you now switch the current type selector (2) to "+", the MA4S shows you the battery voltage.
If the battery voltage is too low, or not displayed at all ,
or shortly flats out after resetting the relay ( the relay will enter in to an inactive state too = disarmed).
The battery test mode, it will confirm the state of the relay.
If you want to repeat the "relay reset" check point, in a short period of time, you have to wait an minimum of five seconds, between each "relay reset" check point (the monitoring circuit needs to get fully discharged first).
Before switching the range selector (1) back in to the "relay symbol",
you must switch it in to another position first ( as proper exiting step of the preview check point ).
The range selector (1) should not stay in the position of the "relay symbol" for a long period,
so to avoid battery drain.
If the relay accidentally switched itself " On or OFF ", due an mechanical shock, start a New " relay reset " check point , so to resynchronize the monitoring circuit.
3.1.2 Automatic battery monitor
The electronic battery monitor triggers the relay, if the battery are low,
In this case the " relay reset function " are electronically blocked.
If the 9V battery , drops below the reference voltage of (6,5V) ,
the relay monitoring circuit gets triggered , and becomes inactive.
After replacing the battery with new , the range selector (1) has to be switched in any other position (for example 750V) for 5 seconds, before initiating manually an New " relay reset " check point.
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With the help of OCR software and Google translate ,
I managed to make an partial translation of the Users manual in English.
And so I will try to upload it here, possibly some more lost souls will get some help from it.
Its not perfect, but understandable.
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Since when , the external case ( isolation of the meter ) ever had an expiration date ?
Since when , the German tools and devices , ( who historically was the leaders in everything have to do of building tools for the manufacturers the last 60 years ) , had safety issues !!
Don't misunderstand my point here, I'm not saying I'd demand replacement or retesting of any equipment over age X, but even the casing DEFINITELY has a finite expiration date. It's probably far enough out that you don't need to care, but materials decay, especially modern instruments made of plastic, and especially instruments intended to be held in oily, dirty hands. I have no experience with safety problems in test equipment, and I'd probably not give it much thought, but as an example, take the various iPhones:
The first iPhone had a mostly metal case: the assumption was that people would hold it and use it as-is. Well, everyone always put some kind of case on their phone before, so they kept doing it, especially now that their phone was super expensive. So the next versions, the iPhone 3G and 3Gs, had plastic cases, since everyone had third party cases between that and their hands. For most, this was fine, but lots of people experienced a problem after two or three years of use that, particularly if they didn't use a case, their phone backs cracked. That ended up being attributed to hand oils causing the plastic to slowly break down, albeit at a more accelerated rate than otherwise. So the newest design is mostly glass, a material resistant to that sort of chemical breakdown.
My point is this: Am I going to trust the fluke that's been sitting on my bench 20 years? Ehh, probably. Am I going to out of hand trust the 20, 30, 40 year old meter I just got at a yard sale? Hell no I'm not, not until I clean it, open it up, and make sure everything looks in order first, anyway. And definitely not if it's made of plastic. Plastic gets brittle and degraded, it happens. I'd rather not find out the hard way when internal corrosion causes a partial short to a nearby trace, or when my hand cracks through the case. Unlikely cases to be sure, but definitely not worth my blind trust.
As Dave always says, it's about measurement confidence. The very idea means that I NEED to do a once-over on my equipment before I can put faith in it, and that includes safety factors as well.
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Well I will partially agree in some of your thoughts .
But always there is an " If " about anything.
For instance , the specific meter looks totally unused,
it is surrounded by leather holster , that is in perfect condition.
The plastic cover is totally unscratched , this meter never had a free fall,
or be used in a dirty environment.
Unfortunately i am unable to open it , so to see the inner parts.
There is no a visible way of opening.
And I am afraid to try any force on it .
Especially when it is so damn accurate at the 1-7.5 DC volts range ( and in every range) ,
the needle is always spot on .
There is no point to be proud for any junk that you can buy on ebay,
except if it is an small treasure, like this unit.
Verified by the Fluke 28II, and also by reference test tools that I own.
I can blame it only for one reason, no buzzer !! :D
Edit :
If something gives to me some more hope, about the quality of the case,
is that its not produced by having in mind to be recycled,
and so it could possibly made to last more than any modern plastics.
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The top line old style Analog multimeters like the Metrawatt & AVO, were usually large enough to provide ample clearance between the internal components which in itself,increases the safety factor.Many of them did not use small PCBs,but were partially or completely wired with insulated wire.
Looking inside them is more like looking at Industrial Electrical circuitry than
anything like the inside of our modern DMMs.
The plastic used,was usually,either Bakelite,which ,if not damaged by dropping,will not deteriorate over time,or some form of reinforced PVC which
looks very similar,& is nearly as tough.
DMMs are very much cheaper to manufacture with our present technology,& are more accurate,but because they are cheaper,their packaging is more likely
to degrade with age.
VK6ZGO
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I can use Babble fish, some beginning German in my past, or my Macintosh could translate the German instructions for you. That will take some time to type it in and read it. I am not sure to help. I saved the instructions. If I have the time, then I will post it.
You have a nice analog meter. It reminds me of the Philips PM2505 from the Netherlands, Holland.
Lawsen
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The best general purpose analogue multimeter the world has ever seen is the AVO8, and more specifically, the AVO8 MKIII.
Production of the MKIII was from 1964 until 1969.
As can be seen from the pics at the URL, www.richardsradios.co.uk/avo8.html (http://www.richardsradios.co.uk/avo8.html) the AVO8s of that time in no way reassemble modern DMMs.
In 1970, Thorn completely re-designed the AVO, value-engineered it. And reliability problems started to appear, due to the use of printed circuits.
I find it incredible that an MKIII will go for a tenner on ebay, whereas a MK5/6/7 will go for up to 150 quid.
I can only presume that people think that "it looks more modern, so it must be better"
Many cheapo analogue multimeters have utilise different scales for AC and DC, which makes for a cluttered scale that's hard to read.
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Hello Lawsen , yes it is an very nice unit .
About the Users manual ,
I do not need more help.
The key function are how to reset the relay,
and I found my way to it , with help that I all ready got.
The PDF manual that I partially translated in English,
has inside few more descriptions about the specs.
For the history , the S at the end of the model, indicates Industrial characteristics.
And this detail makes me to love it more . :)
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which makes for a cluttered scale that's hard to read.
That's was also an major thought , when I was looking to buy an analog meter at 2010.
The one that I got , has an true non cluttered scale , truly practical for all of us , the over 40s ones. :)
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Kiriakos-GR
What about "take it a part"? :)))
Lets see how is the quality compared to Simpson and Triplett :)))
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Kiriakos-GR
What about "take it a part"? :)))
Lets see how is the quality compared to Simpson and Triplett :)))
I was hopping , that after posting this thread,
some one would help me , with some tips about how it opens.
I am aware that even the black boxe of an airplane , they do have an way, so to open them. :D
But the one who will do it , has the knowledge to do it .
With out such information at hand , I do not take the risk to find out how it opens.
From the pictures that I posted , it does not have bottom screws.
The top screws are just for the range switch and front panel ,
and even from there you have no access so to see even the PCB .
My guessing are that the top half casing , with the bottom half casing, are hard pressed .
I will post in few minutes some more pictures , about this " problem "
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Ok here is as far that I would go for now . :)
I managed to pull out the analog organ from the body .
I had select nine pictures full resolution ( no editing ..)
Inside there is dual PCB , the bottom PCB handles the relay,
plus it is used for all the big parts ,
I could describe it as an high amperes highway , that connects to the banana plugs.
The top PCB has the software ( ;D ) , small transistors and diodes. ( ohms range + voltage)
Both PCB looks to me in top shape ,
what looks amazing as detail , are that even the curves of the leads, in the resistors,
they all have the same shape, they must had make an special tool, just for that.
I noticed inside few particles of dust , no oxidation or damage in anything .
I found some pressure points at the top cover, that probably releases the top cover , but I will not try to open them.
Because there is also similar release points at the bottom,
that looks that you have to use an specific tool for those ,
shaped as large fork , and probably only the factory has or had, one of those.
This shaped as fork - key ... must look similar with the special ones for the car stereos ( and usually comes with them) ( easy installation and removal)
The analog organ ( meter) has an transparent window at the bottom of it.
Just an production code , and no other info.
There is three copper plates at the left , I think that is the amperes shunt , I could be wrong too.
For an complete tear down you need to know all the steps , like one - two - three ,
looks as very complex design even to me .
That I have an good experience from hundreds but modern, devices.
And finally looks more modern than those AVO ;D
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It looks that we had lost the fun club of those oldies :)
And so no one noticed in the last picture,
that all the PCB of this Metrawatt , are totally silver plated.
Silver is one step behind from gold , but I am still happy ,
that is not an common solder plated , like the many cheapo ones , out there . ;)
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Wow! That's beutiful build wuality!
Do I se a current transformer below the board?
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Still mickey mouse compared to an AVO ;D
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Still mickey mouse compared to an AVO ;D
Aaaaaaaa ;D I was expecting such an torpedo ,
the only thing that I was not aware , was the sender .. :D