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Active since 7 June 2012  

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Here I will present an issue relative to DMM4050 display Filter  tint and brightness.
I am researching for two months by asking Fluke factory and Tektronix about the date that production factory this stop using Blue Tint VFD filter?

Blue Tint VFD filter this is unreasonably dark, a poor product design and decision of Tektronix which this ended approximately at April 2013, since then and after any newer produced models they carry a Green Tint VFD filter.

Green Tint VFD filter this is what FLUKE DMM models using from the start.
My very own used DMM4050 this production of January 2013, this arrived with Blue Tint VFD filter, immediately I did notice how terrible this is regarding reduced brightness at not acceptable, even under using only in-door lights (at night).

It is unfortunate that FLUKE and Tektronix both do not recognize their old mistake.
Reasonable response would be a newer produced Green Tint VFD filter to be sent free of charge as replacement at any customer whom considers earlier Blue Tint VFD filter as problematic.

While both companies they did not deliver answers in my question, I did discover the truth by my self after cooperating with another ITTSB blog member whom he did sent me pictures of his own DMM4050, this is two months newer production from my own DMM4050.
FLUKE were kind to inform me of recent inventory spare-parts codes, which they can deliver to consumers’  (TEK branded parts).

3476886   4050-2014,LENS 
3476939   4040-8003,FRONT PANEL DECAL 

3476988    4020-2010,FRONT BOOT
3476963    4020-2008,HANDLE

S1 - 8846A-8001,KEYPAD 2454042


Since begging of April 2019, I am now trying to discover how prepared Tektronix Europe this is at handling such spare parts requests.
a) Are they keeping any stock of spare parts in Europe?
b) Are they aware of spare parts codes and pricing?

Head office of entire Europe this is in Poland.
Mr. Maciej Holubowicz he is in charge, we did exchange emails, and now I expecting for final answers.
Due this message I wish to inform any troubleshooter taking seriously contacts resistance measurements,  that he may also read my article  Best multimeter for DPST Rocker Switch contacts resistance? 

As first I wish to thanks Schurter for this product sample.   :)

My very own afterthought for requesting such a sample was for me to discover switch contacts resistance of a 100% healthy switch and also to perform a second inspection  measurement, this be usable by a troubleshooter , so him to be able to make a judgment of this module health status.

Most usual thing and thought, this is people buying also a used DMM, while we all pay attention to inspect a used multimeter in the regard of measurements’ accuracy, exterior product condition, most ones never think that mains power switch condition this has great importance too.

An mains power switch with issues, this can be the cause so sparks at contacts area to appear, such a sparking event it can influence power supply stability, and a multimeter or Oscilloscope this introducing noise when it does measurements’.

From my experiences, a failing power switch this be in the input of a pulsing power supply, it will introduce noticeable noise at DCV rails these feeding an oscilloscope.
Review of known clean Test waveforms will become a challenge, because all waveforms on screen will now appear with noise. 

Now the same failing power switch, if this feeding an classic transformer it would not demonstrate fast to notice side-effects, but eventually sparking will increase temperature and the danger of starting a fire.
But among possibilities there is and another one, some people discovered that while their benchtop multimeter was on soft-power mode (VFD was OFF), when them returned the next day, the meter was turned on.
If Mains voltage did not interrupted due power company issues, then the power switch it self, this started failing.
DMM4050, 4040, 8845A & 8846A all using analog DCV regulation among with switching power supply for the VFD Dot matrix display,  now increased noise at the side of switching power supply, this it could possibly increase noise floor at mV measurements and or other issues.

Therefore and in conclusion, a good inspection of power switch condition this will save you the day.
At specific Schurter power module, power switch this is permanently attached and soldered, in my review I could hardly find clean copper area so to place my Kelvin clips directly at power switch leads.
Even so I did manage to get a good repeatable measurement, and now I am aware that contacts resistance this is 0.5 milliohm.   
My second mission was less difficult, I did select most easily accessible area for Kelvin clips installation, and now this new 3 milliohm measurement this is what every one can use as comparison point.

From today any troubleshooter and visitor of ITTSB blog, he may perform two measurements’ and discover health status of this power switch.
First test lead it should be placed over IEC plug pin, and the second test lead it should touch center pad of fuse holder.
Then just repeat this test with second active IEC plug pin and relative fuse holder pad.
Such an inspection it is now possible with out taking off DMM case, and by this way you may find the truth by not destroying calibration sticker at the bottom of the DMM.

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Therefore feel free using donation links, and demonstrate you appreciation to my Blog with actions.
Regarding Schurter this is a very reliable products maker, but most retail customers can hardly find reasonably priced goods because all three web-shop distributors and their international sales partners, they acting very hostile regarding retail prices.
I did find KG10 this priced at 23 EUR for a single unit, and shipping pricing will add another 18 EUR at least, this makes a total of 41 EUR which I will describe as severe violation of anything called as reasonable price tag.
Did you known that Switzerland this is NOT EUROPE ? 
Even so there is a hidden LAW this aloud Duty-Free if your item worth less than 4.5 EUR, this is equal to a chocolate bar from not a famous brand  :P

Lesson learned, even for free samples from Switzerland,  be aware of 30 EUR customs clearance Fee, in case that your item does not qualify as Duty Free.

In conclusion this project came close to get canceled because of importation fee, but after explaining to local authorities product value and details, their positive decision this now aloud this project to be continued and completed.  :)   
Quick testing has started and here are my findings.

1)   Long button press this is 4 seconds.
2)   This PCB it should stay powered about 10 minutes, and then you may trust the display readings.
3)   Input voltage measurement contain error of  minus 100mV than real
4)   Output voltage measurement contain error of  minus 130mV than real 
5)   The circuit does not reset last voltage setting used after power off.
6)   For charge current less than 600mA, additional heatsink this is not required.
7)   Ammeters circuit this it more accurate.
8 )   Voltage scaling Up-Down this is in steps of 57mV?  This is terrible because there is no chance for you to set a precise voltage output, for example 4.10 V this is 4.190V multimeter reading (U1272A), and this is voltmeter measurement error with combined scaling error due buttons adjustment, which possibly original thought was to be at 50mV steps.

9)   When output is connected to battery, battery voltage above 7 V this is able to keep V/A meter active, and voltage measurement this is possible ( with included error) when input voltage this is disconnected.
This PCB will use approximately 10mA by been powered from the side of the load. 

Generally speaking, with unknown voltage calibration procedure, there is no chance about you correcting voltage measurement error.
Therefore if you think this PCB as Lithium battery charger, then this is not the best for a single cell.
But when there is chain of cells, these 75~190 mV difference from original panel setting, they can be easily seen as not noticeable. 

Additionally because of high switching noise at output, no one should think of it as power supply replacement.
This is a battery charger and this is what it should be used at, a battery cell does not care of high switching noise at 150 kHz.

From the other hand we should never forget that it is a major challenge about getting accurate voltage reading from a dirty DC power source, especially with a low cost VA meter.   
Therefore we should always evaluate carefully all plus and minus before a decision is made. ;)
132 Days for delivery ?  from Solomon Islands ?  (This is a small planet next to moon  :P )

Either way, this project gets back on track and I am planing to use a fancy case and power supply.  ;)
I have good news to share  :)

SCHURTER HQ Lead Qualifier, accepted my sample request and product this is shipped today with TNT economy.

Therefore my very own exploration of KG10 quality standards by the use of highest quality Milliohm Meter  RM3542A
(from HIOKI Japan) this will happen soon.    8)
In the past 20 years I have never see a reliable copy cat from China.
While we have the delusion that a cost effective product this can be a replacement of banana plugs made under European or American quality standards, reality this is much different.

Personally I was have a simple expectation, that I will discover an Asian female binding post which will accepts entire length of a male banana.

I will leave again pictures to do the rest of the talking.
In the positive side of things, I have seen and worst than that regarding product design.
What is questionable at specific factory work, this is the quality of plastic parts (isolator) regarding mechanical stress and temperature limits.

€4.93 EUR for 10 of them it is somewhat reasonable eBay price, but this is the upper limit or what is called reasonable when you trade with China.
When manufacturing cost this is 0.04 EU-Cent per its one.
SCHURTER KG10 or  KG10.6101.151 ( IEC C14 ) this is the full description of this  Power entry module without line filter at the back of these DMM.

Originally I thought to research and discover my options, in case which I will need to replace this power switch.

My search started with keywords KG10, then I did realize that this is a SCHURTER product, and after of several hours of additional research, I did the final discovery that SCHURTER does not offer replacement part of single power switch for this module.

Instead they try selling entire power entry module at high price due a few retail channels to any one seeking just one.

KG 10 in quantity of 1000 it will cost you 3.5 Euro.
While build quality of KG10 this is upon high standards, neither it silver plated Mains voltage switch and neither it build quality of fuse drawer alone, these can justify 20 euro retail price, when a made in PRC  IEC C14  plug and switch this has a cost of 1.5 euro shipped.

SCHURTER this brand thinks as supplier for industry customers, it does follow certifications, and within 2016 ~ 17 they do deliver newer KG10 with improved fireproof housing.

I did a product sample request to SCHURTER, among other details which I wish to inspect, I need to make contacts resistance measurement at totally unused product, so to become aware of absolute lowest values.

Below it is my KG10 (parts and details).   :)

Regarding voltage compatibility within EU, in the question of using 220 or 240V setting, the answer it is not that clear.
Over voltage this is considered anything above 220V +6% but even so this is not considered as decision factor.
Practically selection of 220V setting this will serve better speaking of tolerances at under voltage condition, and for this reason alone it is recommended using 220V transformer input tap.
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