FADOS9F1-tester for finding faulty components on boards.

AlbertHall

Joined Jun 4, 2014
8,512
It would help if the manual was written in English rather than (appearing to be) badly translated from some non-English version.
 

AlbertHall

Joined Jun 4, 2014
8,512
"Chassis must be isolated and grounded. Connect the chassis ground connection point of
the probe is the same as your computer, careful to avoid the potential difference."
 

Thread Starter

bob2

Joined Jun 15, 2019
139
This is what interests me from the description of the tester.
Figure 73: Measurement of a capacitor inside and outside of the circuit
Test Voltage : ±1V,
Is the test voltage too high?
 

AlbertHall

Joined Jun 4, 2014
8,512
I don't know of any capacitor that would be damaged by 1V but if in circuit it would be enough to turn on semiconductors but that isn't a problem if you are you are comparing a working unit and a suspect one as they should both show the same squiggle.

When I was working in a service department we had a salesman come to demonstrate a machine that used the same method as this. We weren't impressed though it was a fun toy.
 

Thread Starter

bob2

Joined Jun 15, 2019
139
but that isn't a problem if you are you are comparing a working unit and a suspect one as they should both show the same squiggle.
It’s good when there is something to compare with. But basically it happens quite the opposite.
In fact, the topic of finding faulty components is quite interesting and has practical meaning for those who repair various equipment. Those who are involved in these things know that there is a wide variety of different devices and testers that make it easier to solve problems of varying degrees of complexity.
This is one of such testers that uses modern technology and the achievements of digital technology.
Judging by some videos from the Internet, he has certain positive aspects.
 
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Thread Starter

bob2

Joined Jun 15, 2019
139
Hi
Frequency.
High Frequency : 355.4 Hz
To test capacitors, the frequency is too low. Who worked with this device, why is such a low frequency chosen?
 

bfrad

Joined Dec 2, 2019
2
Typically VI testers/signature analysers work in the 10Hz to 5KHz region. Quite often you find yourself adjusting the frequency to create a more meaningful component signature. We build something similar to the FADOS unit <SNIP>, although we go between 10Hz and 1KHz - it's surprising just how useful the low end of the band is useful. 355.4Hz is a weird choice.

Pure capacitance can be measured at any pretty much any voltage - although normally you are looking for a semiconductor junction along side, so practically all measurements happen at 1V and above.

ABI Electronics (here in the UK also make signature analysers and they have some videos on YT, and Huntron have some content also which might help.

Moderators note : removed comercial link
 
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Thread Starter

bob2

Joined Jun 15, 2019
139
Hi
I understand you are a developer.
We build something similar to the FADOS unit (<SNIP>), although we go between 10Hz and 1KHz
This is already good.
Let's start with capacitors.
Does your analyzer detect faults on all types of capacitors?
What types of capacitor faults does your analyzer detect?
 
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bfrad

Joined Dec 2, 2019
2
Hi bob2,

Analog signature analysis is not so much about quantifiying what the fault is (e.g. high ESR capacitor), but finding what parts are faulty and tracking down the areas to look at.

The signature of a component (say the B-E junction of a transistor) out of circuit will often look different to the signature of the same junction when it is in-circuit due to the surrounding circuitry. Traditional signature analysers had two alternating channels and you would compare the signature of a junction/component/pin on a 'golden' sample with that of the 'suspect' sample. If the signature is different then you know the problem is usually in that area. Modern units (like ours), it is possible to store signatures for a golden board as file, then you don't need the golden board on-hand to carry out a test.

Experienced operators can also use an ASA without a golden sample, you get to know what sort of signatures look right for a component (i.e. D-S on a MOSFET creates a straight line, you know the junction is short. Which brings me onto capacitors - you can 'see' the ESR of a capacitor with an ASA and it is also possible to see other faults and non-linearities, but it is not optimised to do so. You fill 'see' the circuitry connected to the capacitor and this is likely to complicate measurement.

The FADOS unit shows a potentially simplified version of what the electrical circuit looks like to the ASA - it's certainly impressive to do that - but in-my-opinion not that useful. Huntron (pioneers in signature analysis) have a nice paper on it: http://www.huntron.com/sales-support/pdf/ASA-paper-extract.pdf
 

Thread Starter

bob2

Joined Jun 15, 2019
139
Hi bfrad,
Thanks for the general information. Some points are of some interest.
But you still have not answered my questions about the capacitors.
Does your analyzer detect faults on all types of capacitors?
What types of capacitor faults does your analyzer detect?
 
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