Welcome to ITTSB Forum, extension and content sharing platform of ITTSB.EU Blog

Registration this is Free, to support this Blog please use our donation links available in our Blog page and forum.

Copyright Notice:  All content of this web site this is copyright protected.

Recent Posts

Pages: 1 2 3 4 5 6 7 8 9 10
Handheld multimeter / 2018 - Multimeter Repairability Score ?
« Last post by Kiriakos GR on March 21, 2018, 10:49:06 PM »
This topic it is here mostly about feeding you with thoughts which they will help you back, prior making your next buying decision regarding multimeter.

In past six years ITTSB blog this delivered lots of product reviews, and a huge amount of applications examples these be almost as live demonstration of what modern DMM can do and of how they should be used.
And all such content this is now hosted at ITTSB Blog forum, and because of that fact, many visitors even today they confuse this content with anonymous electronics repair forums, and they send me emails about helping them in their repairs, something which I do not do.

Multimeter Repairability Score as phrase in past years it was meaningless for us working with electronics repairs.
Especially in past decades, repair of your own multimeter this made by thru-hole electronic parts, it was your obligation to fix it back in case that it was damaged due careless handling.

While recent electronics parts technology this improved and it did shirked down electronics components size, component level repair this is still possible but not always.

Respectable brand names which manufacture real multimeter, they use branded microcontroller and input protection electronic parts, and also following specific principals (engineering) regarding printed circuit board (PCB).
Such modern made multimeter it has over-voltage protection at ohms range and possibly in to other measuring ranges, and this new protection makes such multimeter be almost immune to damage.

From the other hand 100% of cheaply sold multimeter, these are prone to damage and not repairable most of times.
Unfinished chip construction this serving as microcontroller, at environmental temperature differences (cold – warm –cold – warm changes) and even due mechanical vibrations,  such unfinished chip this is prone to die due simple insertion of atmospheric air ( oxygen) in it.
At unfinished chip construction what are missing this is outer protective cell, and also proper leads for soldering over PCB.
In the name of ultimate profitability the product that you receiving similes to tuna fish can, this coming also with sort expiration date. 

In conclusion,
There is no Multimeter Repairability Score at cheap multimeter, unfinished chip construction this is mainly the source of Evil, such poor methods was previously used exclusively from anonymous factories in China, but who would thought that American based DMM manufacturer would also use this method at their own low-end products’ line.
Respectable brands from Japan, Taiwan and even in Europe, all are in denial using such poor manufacturing methods.
Therefore next time that you will come close to a buying decision, you should consider that a tuna fish can this is always cheaper, than a true multimeter which will serve you for one or two decades, or more.

Update :  Since June 8, 2017 and up to date I am measuring nine months of silence. plus 12 days.
In all this time frame RIGOL news wall stays empty and opinion of ITTSB Blog no matter level of raised voice, this is now considered as well made and an sincere estimation.   

Few years ago ITTSB Blog has the opportunity to write an in depth product review about DE-208A that is a product aiming professionally working audience.

While DE-208A it is superior as measuring device and build quality among safety both are at high standards, what seemed as negative this was the price point.

Back then it seems that management of DER EE co., Taiwan, it did receive wrong advice due their own marketing team, of what international consumers’ was willing to pay for it.
In the beginning, pricing expectation about DE-208A this was to placed at 400 USD price range, overall  performance of this multimeter this is very close to FLUKE 87V.
DE-208A comes with two additional advantages that FLUKE 87V does not have:
a)   mV range this measuring with precision from single millivolt , so this to support external AC/DC current clamp probe. Such an advantage helps DE-208A to be considered as essential (first choice) multimeter and for audio applications.  At 2018 FLUKE 87V this is now an old meter, limited to electrical applications, when DE-208A this is still a multipurpose multimeter.     

b)     Second advantage, this is data logging capability due USB cable.  Such feature was mainly an advantage introduced from Agilent (Keysight) U1272A. 

Now it makes sense that DER EE co., Taiwan, by thinking that their DE-208A this is one product standing between FLUKE 87V and Keysight U1272A, that this can also stand at that price range.
We are now four years later, and DER EE co., Taiwan it did realize their mistake.
Latest pricing equalization this is at about 150 Euro as retail price for DE-208A.
Such a move this is now an opportunity for DE-208A this to win market share and appreciation from the technical community.

DE-208A under the microscope:

a)   Very advanced electronics (speed – precision – bandwidth)
b)   Range switch design (Made in Japan)
c)   High quality banana plug inputs & safety standards for EU & US
d)   Multimeter body this has layer of rubber material (equal product design to U1272A).
e)   And finally only it front mask cover of the LCD display this seems as poor choice of materials in my eyes even today.
f)   But when DE-208A this is offered at 150 Euro and below, I am ready to accepts this product as good over all choice even if aesthetics this is not it strong point.

In conclusion,   
Within 2018 four brand names are dominant in the market of modern and well made multimeter for professional use.
And these are HIOKI (Japan), Keysight U1272A, BRYMEN (Taiwan) and DER EE (Taiwan).
It is unfortunate that other brands with small or larger brand reputation, does not shown identical bravery at equalizing the price of their offerings, neither they care to offer products with updated features in a market that always moves ahead and this now changes more rabidly than ever.

Speaking of signs of innovation, HIOKI invested more thought recently so their high quality handheld multimeter DT4282, this to deliver more in the area of electric vehicles, with AC/DC volts measurement (high speed) and both values are displayed simultaneously.
U1272A this is also capable of AC/DC volts measurement but at much slower display update speed.

For latest pricing and availability you need to contact DEREE website, they do accepts PayPal.
Another option this is offerings due eBay.
I am simply informing of latest news, final purchase decision this is always your own.
DER EE/ DE-208A multimeter Review – By the eye of the Industrial electrician.
Product design flaw spotted from one owner of DSOX1102G and a video shown on YouTube.

Symptom: 24V regular transformer output this measured with significant error by switching from DC to AC coupling.
ACV-rms measurement shown more than 10 % error even in comparison with a rms multimeter.

Keysight justified this flaw by their R&D saying:
AC coupling is useful for view waveforms with large DC offsets. 
AC coupling places a 10 Hz high-pass filter in series with the input waveform and removes  DC offset voltage from the waveform.  Keep in mind that 10 Hz is the filter’s -3dB point (and still has some attenuation).
AC coupling should only be used on sine waves greater than 100 Hz and square waves greater than 200 Hz. DC coupling should be used on frequencies lower than that.
So, it's basically a filtering thing when using AC coupling.

ITTSB Blog ....
I did run identical test at my (GW Instek)  GDS-2000A and there is no such measuring unbalance.
7V RMS  at 50Hz  was produced by an AWG generator.
I did double Verification by using regular probe at times X1 & x10 and also by using  single high-performance 50 Ohms cable with BNC plugs.

I wanted to explore if impedance mismatch this can be held responsible in any way.

If you do using Keysight 1000X scope or 2000X or 3000X,  you better check how it performs, because caused error in electrical measurements this could be huge.
Keysight marketing team in past five years it does ignores professionally working electricians bloggers, therefore too bad for them.

Το 1988 τελευταία μου χρονιά ως ηλεκτρολόγος στο θρανίο,  ρώτησα τον καθηγητή, γιατί δεν μας παρέχουν πληροφόρηση πάνω στα νέα ψηφιακά όργανα μετρήσεων? 
Μου απάντησε ότι αυτά θα τα μάθατε έξω από εδώ.

Αυτό που τεχνηέντως μου απόκρυψε είναι ότι εάν δεν αγοράσεις από μονός σου τεχνολογία αιχμής, δεν θα μπορέσεις να αποκτήσεις γνώσεις και εμπειρίες που θα σε βοηθήσουν να ακολουθήσεις τις τεχνολογικές εξελίξεις η ακόμα και να πρωταγωνιστήσεις στην επαγγελματική σου εξέλιξη. 

Εάν υπήρχε κάποιος άλλος πρωτοπόρος  τις περασμένες δεκαετίες να στήσει ένα  ITTSB Blog,  θα του ήμουν ευγνώμων και υποστηριχτής του.
Βέβαια ποτέ δεν είναι αργά ώστε να πολεμηθεί η ηττοπάθεια, η αδιαφορία και η αμάθεια, και λογικό είναι να μοιράζομαι την ηθική ικανοποίηση της προόδου που έχει επιτευχθεί με την σημαία του ITTSB Blog, με όλους τους συμπαραστάτες και συνεργάτες μου,  οι οποίοι βοηθώντας εμένα, βοηθούν χιλιάδες νέους και τον τεχνικό κόσμο γενικότερα ώστε να ενημερωθούν και να συγχρονιστούν με την πορεία των εξελίξεων.
Τα στατιστικά επισκεπτών του Blog  για έξη συνεχή χρόνια αποδεικνύουν ότι σε επίπεδο χωρών, οι Έλληνες είναι ο δεύτερος σημαντικός όγκος επισκεπτών, μετά την Αμερική.                 

Σαν σήμερα γιορτάζω την απόκτηση του πρώτου μου παλμογράφου για επαγγελματική χρήση, τον οποίο παρέλαβα το 2013.   

News from China:

Agitek Test Instrument Training Institute is a free electronic test instrument training service supported by the company's technical support team.
It has five senior trainers and has conducted more than 300 free training services for customers in the Northwest.
And also at about 1000 people who joined in these lessons due their own free choice.


ITTSB Blog comment:
In 2018 that most to all of our known as international brands with western logos and origin of electronic test instrument, they deliver training service this always offered under fee ,  significant in size Chinese electronic test instrument industry gives free of charge training.
It is not required much of imagination that in China there is people whom thinks to better prepare their own nation at any cost, so their children to be better prepared in the years to come.

In case that the word nationalism this causes to you salty feelings, just be aware that there is no world that all we can have equal share of success with out giving our own personal battle, or in the next level that is as nation, in both cases it is required strategy and decisions and determination.

Practically several brands in USA and Europe, they should feel guilt’s about converting to merchandise even training related to electronic test instrument.
They have fail in the sector called as obligation to society and their action of planting few trees this is not a worth mentioning contribution.
Happy PiDay to all our visitors with western origin and any one celebrating #Pi Day  :)
Several weeks ago I shopped 30 pcs of identical type LED about using them so I to repair two battery chargers.
Supposed electrical specifications:
2.3V for RED (20mA)
3.2V for Green (20mA)

My repair’s when successful and I thought to buy some extra stock of such LED for future use, and I did that by shopping from another seller.

Now I did receive 50 LED which none of them this is 100% similar to its other.
First indication which alerted me this is level of luminosity at RED color, it seems that I won a jackpot,   entire batch of such LED they have issues and differentiate at RED color.
Second jackpot this is broken compatibility with previously shopped LED of this type.

Third Jackpot this is that such LED they can work as replacement of damaged LED’s because of their different and lower forward voltage at RED color.
Fourth and last Jackpot this is manufacturing quality at one electrical parameter this named as:  Tolerance of forward voltage (example) ±0.05V
Branded LED manufacturers they do deliver such a specification, and this works as warranty that entire batch of their products they will deliver similar luminosity at specified operational forward voltage.

These 50 pieces of garbage which I got, after careful testing these now could be classified in four categories.
1)   Dead ones  DOA (five pieces)
2)   Vast majority  (2V  16~24mA)
3)   Low performance ( 2V  4~6mA  nine pieces)
4)   High – over-driving  (2V  26~30mA ten pieces)

Ebay seller was notified and he were honest and refunded.   
Not even one true electronics engineer or troubleshooter would use words as “screen of death “as description of one Oscilloscope which does not boot properly.

Either way, they are two reasons so one Oscilloscope to hang at boot.
First one this is failed firmware update, and activation of second boot loader (emergency boot loader) this is possible with few additional steps.

Second and highly possible reason for all oscilloscopes designed with Soft-On power circuitry, this is their power supply.

Soft-On power circuitry and power supply failure these are bonded meanings from day one.
This is why among my other preferences there is a regular power switch to be in control of all my equipment's’.   
And in case those regular powers switch this missing then I do unplug this equipment from mains when this is not in use.

Workbench Master Power switch this is not new concept.

My advice if you are at this unpleasant situation and your Oscilloscope this does not boot, this is you to purchase one bright new power supply for it.

Yes you need to come in contact with the manufacturer of your Oscilloscope, and if your inquiry fails then you may research further at buying directly from ODM and maker of this power supply in China.

I do assume that pricing and shipping cost would never exceeded sum of 120 Euros even at most unreasonable situation.
Good quality PSU for Oscilloscope they use first grade of electrolytic capacitors, and they are also thoroughly inspected, therefore a reasonable price would be 45~70 Euro plus 20 Euro for shipping.

One good source looking for power supply this is http://www.lytec.com.tw
Pages: 1 2 3 4 5 6 7 8 9 10


Blog YouTube facebook twitter PayPal Donate Link

ITTSB Blog Sponsors

protosnet.com - Internet solutions

2017 Review samples received by

HIOKI EE Corporation - Japan Times Electronics ltd UK Vishay Foil Resistors POWERTRON resistors - VPG DER EE Electrical Instrument Co., Ltd.