Recent Posts

1

Panel meters ( Analog or Digital ) | Energy Usage Meters / Re: Panel meter 5-30V DSN-DVM-568 three digits LED, Calibration tests ITTSB Blog

« Last post by Kiriakos GR on July 21, 2017, 01:15:05 PM »

Speaking of PCB of DSN-DVM-568, there is nothing special to it.

Beware: When this meter is in operation with 24V for five hours L78L05 Voltage Regulator (5V 100mA SOT-89 SMD) this run hot to 52 Celsius.
According to datasheet L78L05 SOT-89 SMD, Max operating temperature this is 125 Celsius.

2

Panel meters ( Analog or Digital ) | Energy Usage Meters / Panel meter 5-30V DSN-DVM-568 three digits LED, Calibration tests ITTSB Blog

« Last post by Kiriakos GR on July 21, 2017, 01:00:20 PM »

Today I did set under the microscope of ITTSB Blog this Panel meter 5-30V DSN-DVM-568  three digits LED.

This is an item priced on eBay at best at $1.54 USD with 35 to 40 days shipping schedule.

Technically this is not an impressive item, in my tests it accuracy were found to be 2% that is way too much, this thing it is advertised as 1%.
This 2% error it is introduced in 95% of range, and you better take a good look of the pictures bellow.

Practically this meter with such terrible accuracy, this varying from 1.6% up to 2%,  this is not recommended as voltage monitor for lithium batteries.
My opinion this is that this meter it could have a good use only in vehicles using 12V or 24V, and nothing else.

Use of such a meter over a power supply, this is possible but it is not recommended if you care for precision work.

Speaking of wires ,  this meter supports three wires connectivity. 
R3 this is short component, this must be removed for three wires connectivity. 
As soon R3 this is removed, then VT contact point this now becomes Volt meter (Power supply input).
Volt meter consumption this is varying too,  sweet spot this is 6V / 10mA ,  above 12V consumption varying from 12~14mA.
Highest consumption recorded at Max 33V that is end of this meter measuring range, and consumption was  16.8mA
 

3

Handheld multimeter / Multimeter and digital VFD Filter active at 400Hz (graph of operation)

« Last post by Kiriakos GR on July 20, 2017, 11:11:24 AM »

Several quality multimeter they come with VFD filter or this also described as Low Pass filter.

Filters are useful to suppress harmonics, and actually unwanted harmonics.
In the application of variable frequency drives (motor speed control units) at 400 Hz max operating frequency, any higher signal above 400 Hz mark this is unwanted.
Reliable voltage measurements should be made by Filter this set to active state.

In the market they are several VFD controllers, max operating frequency this can be 100Hz or 200Hz or 400Hz.
Most to all multimeter manufacturers they design or use digital filters them aiming 400 Hz systems.

Bellow there is a graph of operation of such a digital filter this used by HIOKI DT4282
     

4

Evaluation and Testing of ups ( Uninterruptible Power Supply ) / What's your APC UPS telling you? (video)

« Last post by Kiriakos GR on July 19, 2017, 09:50:20 PM »

Very informative video even for electricians.

The presenter it does on camera simulation of electrical situations (conditions), as for example inverter  Trim / Boost, and load change. 

 

5

ITTSB General Discussion / Free of charge, Large electronics project box - MGE Pulsar ESV 22+

« Last post by Kiriakos GR on July 19, 2017, 06:12:51 PM »

Another one of my lucky days     a neighbor and repair man of computers did a cleanup at his storage, several old computers and other peripherals take the road to recycling facility,  but this box attracted my attention.
 
MGE Pulsar ESV 22+ this is ups made at 2005 or so, ups product concept this is close to APC 2200 units which had two metallic cabinets at default setup.
Second metallic cabinet this was dedicated for batteries storage.

MGE Pulsar ESV 22+ internal PCB this comes very close to architecture of APC SUA-1000XL , this translates that also this MGE ups was designed for 24 hours or more of operation, this serving small servers and similar loads.

I our times no one makes dedicated metallic cabinets so them to host medium to large in weight power supply.
Thanks to my good neighbor this metallic case now belongs to me,  and soon or later it will have a second life by serving in one of my upcoming projects. 

In case that you like to learn more details of this huge EMC Filter follow this link. http://www.ittsb.eu/forum/index.php?topic=1333.0
   

6

ITTSB General Discussion / Boost Firefox speed and performance by a simple tool (no software installed)

« Last post by Kiriakos GR on July 19, 2017, 01:55:03 PM »

To all ITTSB Blog readers using Firefox, I have a recommendation to pass along.

Up to date I was not aware of Firefox internals speaking of databases that the software creates with out the user to be aware of.
I am talking of internal Firefox software engine which by it self it starts gradually to steal  performance from Firefox Browser by adding lots of delay at startup and browsing.
For several years Firefox developers were accusing end users, that their choices regarding Add-on App, this is the reason which causes Firefox to slow down.


SpeedyFox  this is a New software which it does work by improving condition of hidden Firefox databases, and then Firefox software works again with speed of light 
No Installation, no secrets, no scam.
I did congratulated this software developers team for their work,  and here is the link for you to get this tool.

https://www.crystalidea.com/speedyfo

My tip to all, because this software does not install anything, what you need to do this is save itt and run it once when you get the feeling that Firefox started behaving again as a pregnant elephant.
( Simple as that) 

7

Electrical Metrology for enthusiast / Re: Good quality - Male BNC plug to 2 x 4mm terminal adaptor (Taiwan)

« Last post by Kiriakos GR on July 19, 2017, 02:23:32 AM »

I have good news, the seller shown honest and refunded me right away.
Now I need again to find another source.

8

ITTSB - Small projects by Kiriakos & User reviews / Build like a tank JC4-1512C EMI filter 15A (Made in Taiwan)

« Last post by Kiriakos GR on July 18, 2017, 10:46:28 PM »

Today I got as gift one ups MGE ( Pulsar Esv 22+), only the metal case of ups controller,  so to reused it in another project of my.

By removing all ups back plate items ( IEC plugs) and other bits, my eyes caught a huge EMI Filter, this build like a tank, this be quite large in dimensions.
Metal case and shielding brings memories from military RF equipment's.
 
Generally speaking this item it has truly impressive appearance and construction.
For a minute I had the impression that this Taiwanese manufacturer just wanted to impress MGE and EATON brands.
But by inspecting product specifications’ and  specific EMI frequencies’ Filtering, now it is obvious that such a monster EMI filter was build to order.
This filter does incredible suppression at RF range of 1~30 MHz, now according ups age, this filter it is made at about 2003 ~ 2005, and range of 1~30 MHz this was SSB communications of fighting Navy in several countries including U.S.A. and Greece. 
Therefore this special touch up as EMI filter was deliberately made for ups sold to the army.

Now enjoy the pictures of this interesting and high quality engineering from Taiwan.
http://www.powertek.com.tw/cp.asp?id=649

9

ITTSB General Discussion / Re: Pioneer Project 120 vintage speakers and crossover filter inspection

« Last post by Kiriakos GR on July 17, 2017, 10:45:06 PM »

With the help of my LCR using it as signal generator and with my Koss Headphones, I did managed to decode this three way Crossover.
I am not a speakers specialist and one coil in parallel with Mid-range line this confused me allot.

After decoding  now everything looks clear, and I did rewire everything, and even replaced the speaker input terminals with a better one.

Now that I become an expert, I am going to repair and the second cabinet.
Despite the fact that those cabinets were shipped with low power drives, these cabinets are quite large, and able to offer sweet bass.
While these speakers designed to be budget Home-Audio speakers, in 80s the sounds where mostly made of natural instruments.
Therefore for people with taste for modern electronic music, and heavily distorted bass,  these speakers are not made for them.

PIONEER in Greece (90s) were quite popular, mostly because of the tremendous availability of drives as spares, DIYers was buying PIONEER drives and made their own cabinets.
Also PIONEER speakers was easy to repair by a simple drives exchange.
But PIONEER Crossover was coming only with PIONEER branded pair of speakers (Never seen single Crossover in retail market as spare part).
Generic Crossover with PIONEER drives among with DIY cabinets, this never worked well.

The King of quality made Crossover this was PHILIPS in Belgium.
Source of innovation speaking of new technology tweeters, this was again PHILIPS in Belgium.
True sound speakers development and product design testing were made again by PHILIPS in Belgium.

Therefore for audiophiles like me back then (90s) our choices were limited.
a) B&O which no one can afford.
b) PHILIPS for affordable high Performance.
c) JVC or Panasonic Technics ( Medium performance from reliable brands)
d) PIONEER drives and DIY speakers.

Today I am not in need for another pair of speakers, but these ones I am going to keep them, to resale or use them in a later time, most worthy part in them this is the design of PIONEER Crossover, with new pairs of drives, these speakers will deliver a much pleasant sound than most modern budget Asian pairs of speakers. 


 

10

Electrical Metrology for enthusiast / Re: Good quality - Male BNC plug to 2 x 4mm terminal adaptor (Taiwan)

« Last post by Kiriakos GR on July 17, 2017, 12:47:48 PM »

I got cheated , I feel mad because my own work project this will further delay, but at the same time I feel happy, because now I have the opportunity to demonstrate in public close-up pictures of worst quality parts.

Long story sort, these are worst quality banana plug adapter.
Material this is plastic ( cheap plastic as the one used for toys that they do crack on die on impact.
BNC pin this is not properly machined, there is no sharp tip on the pin.
BNC plug  (negative side this gets all the way at female BNC (instrument terminal) this is terribly machined, poor bad made shape.
Both details these are critical, and they can destroy female BNC plugs. 

Real quality banana plug adapter, this has molded (rubberize surface) as external plastic cover.
High voltage similar parts from Pomona brand they have different material ( it could be Bakelite).

Additionally I decided to use HIOKI resistance meter, as another way of spotting  build quality differences.
Now my last word about this topic, this is that major problem with those (FAKE) banana plug adapter this is quality of mechanical construction.
Anything that can cause damage of BNC plugs over an Oscilloscopes and similar high price equipment, this is and must be considered as garbage BNC accessory. 

Replacing BNC plugs over equipment due mechanical damage, this is a costly and time consuming adventure, therefore be careful of your choices.
In my case I got cheated, but I am ready to defend my upcoming eBay case.