Digital Troubleshooting and testing - Electronic Circuits Projects Diagrams Free

walters · 21st August 2005, 05:14 AM

What are some basic Digital Troubleshooting techiques?

When digital troubleshooting using the logic probe how do you know if the digital componenc is working right?

How do you signal trace a digital circuit or component to know if its working right to track down the componect thats not working ?

For digital troubleshooting how can i use the oscilloscope to test the digital components and circuit

a.) Test and display the timing ?
b.) See the On and off timing?
c.) What else can i test for on the oscilloscope?

Thunderchild · 21st August 2005, 06:19 AM

just test the inputs and outputs with the logical proble and see if they corespond to the truth table of that particular gate as a starter !

walters · 21st August 2005, 06:21 AM

For Testing Gates in a Circuit do i inject a HIGH or LOW signal to the input of the GATE and use the logic probe on the output of the gate ?
with the truth table like to me ?

Thunderchild · 21st August 2005, 06:26 AM

yes carry out all the possible combinations so for a two input gate that is 00, 01, 10, 11 and see if the out put is correct for each state. just make sure u r injecting the apropriate signal for that type of gate and if u r injecting it externally and not testing the signal already present then i advise u to remove the chip from the circuit (these should be pluged into sockets so that should not be a problem) maybe using a bread board or standalone socket with wires to it will help u in the testing.

walters · 21st August 2005, 06:37 AM

THanks for the information

How can i do in-circuit testing for digital components?

Gates troubleshooting in-circuit testing?
Clock troubleshooting in-circuit testing?
registers troubleshooting in circuit testing?

How do i test and troubleshoot decorders or encoders?

Thunderchild · 21st August 2005, 06:54 AM

u can test te circuits own signals or inject a signal and hope for the best there generally should not be a problem to remove the chip is just a precaution - u did use sockets in your project DIDN'T you ?

walters · 21st August 2005, 06:59 AM

Well im talking more about a product for company's that make a board
or circuit thats digital and knowing how to troubleshoot it and how to start
testing digital componects that my problem of knowing digital troubleshooting skills what should i know? and how to do this?

Thunderchild · 21st August 2005, 07:20 AM

well as for the professional way i have no idea and not having an osciliscope because of its cost i would resort to a simple homemade probe but the method is up to u perhaps u should try and find a good book on the subject if u want to go into it on that large a scale as i suppose u would have to know the various signal levels that each family of chips use.

walters · 21st August 2005, 07:31 AM

Yes whats the professional way for digital troubleshooting ?

Thunderchild · 21st August 2005, 07:39 AM

there is no specific method i suppose it depends on the situation what u prefer and what u have at hand i mean a multimeter can be used if nothing else is at hand. i think the most professional instrument available i cannot remember the name of but is is like an osciliscope and can veiw in some up to like 16 signal simutainesly. basical i suppose what makes a professional is knowing how to deal with each situation. some companies even design for their products custom circuit testers that have a board with dozens of probes sicking up and the faulty circuit is placed on top and the whole board is analysed at once but this is a computerised machine and is specific for each board and is only feasable on a large scale. it just depends on what u r working on and what u have available.

walters · 21st August 2005, 07:45 AM

How would u test digital components like registers,encoders,decorders, decimal to hexadecimal, gates?

Thunderchild · 21st August 2005, 07:50 AM

with the digital oscilisope thing and a signal injector. connect the inputs of the instrument to the outputs in quetion and probe with the injector and verify the results. if u r dealing with encoders and decoders then i think u have like 8 inputs ? for the different addresses so perhaps something like a word generator is necedary and can be wasily built it is just as multy out put signal injector

walters · 21st August 2005, 07:55 AM

But how do i know if the encorders and decorders are working right?
I got the oscilloscope on inputs and the outputs

Yes the encoders have 8 inputs and the decoders have 8 outputs

How do i test the Encoder and decoder Addresses? with a probe or oscilloscope

what do Encoder and decoder Addresses look like on a oscilloscope ?

Are Encoder and decoder Addresses voltages? or a waveform?

Thunderchild · 21st August 2005, 08:05 AM

digital 1 is normally VCC and digital 0 0volts so onthe oscilicope singal tracer or what ever u use u will see 0 or VCC (or there abouts as theory is never practice even in digital stuff) so say u have the encoder. this has for example 3 address inputs 2 to the power of 3 is eight therefor u can have 8 inputs being encoded into 1 output when u input address 0 (000) input 0 is sent to the output when u input ADD 1 (001) in 1 goes to output and so on until input 7 and add 7 (111) so u have to produce all the 8 addresses (000 - 111) and verify that the signals uinput to the relevant input are coming from the output. basically just get the blasted truth table and create urself all the states on it. u also have to understand what the chip does proporly to know what is going on and be able to understand the data sheet as it may make a very breif explanation of the chip and it's truth table.

walters · 21st August 2005, 08:12 AM

Is there a easier way to do this without truth tables testing digital componects checking the inputs and outputs the truth tables can take along time to check all the High and low states don't you think thats really hard to track a digital componect down thats not working right i would have a bunch of truth tables then?

21st August 2005, 05:14 AM	(permalink)
walters Banned	Digital Troubleshooting and testing What are some basic Digital Troubleshooting techiques? When digital troubleshooting using the logic probe how do you know if the digital componenc is working right? How do you signal trace a digital circuit or component to know if its working right to track down the componect thats not working ? For digital troubleshooting how can i use the oscilloscope to test the digital components and circuit a.) Test and display the timing ? b.) See the On and off timing? c.) What else can i test for on the oscilloscope?

21st August 2005, 06:19 AM	(permalink)
Thunderchild Experienced Member	just test the inputs and outputs with the logical proble and see if they corespond to the truth table of that particular gate as a starter ! __________________ I AM the exeption that disproves the rule in many ways but the rules still apply (unfortunately) my site:www.simons-photography.com http://rushdenrotaract.org.uk see also http://www.bigstockphoto.com/account...fid=m2URATYch5 http://www.redbubble.com/people/simonsphotography

21st August 2005, 06:26 AM	(permalink)
Thunderchild Experienced Member	yes carry out all the possible combinations so for a two input gate that is 00, 01, 10, 11 and see if the out put is correct for each state. just make sure u r injecting the apropriate signal for that type of gate and if u r injecting it externally and not testing the signal already present then i advise u to remove the chip from the circuit (these should be pluged into sockets so that should not be a problem) maybe using a bread board or standalone socket with wires to it will help u in the testing. __________________ I AM the exeption that disproves the rule in many ways but the rules still apply (unfortunately) my site:www.simons-photography.com http://rushdenrotaract.org.uk see also http://www.bigstockphoto.com/account...fid=m2URATYch5 http://www.redbubble.com/people/simonsphotography

21st August 2005, 06:54 AM	(permalink)
Thunderchild Experienced Member	u can test te circuits own signals or inject a signal and hope for the best there generally should not be a problem to remove the chip is just a precaution - u did use sockets in your project DIDN'T you ? __________________ I AM the exeption that disproves the rule in many ways but the rules still apply (unfortunately) my site:www.simons-photography.com http://rushdenrotaract.org.uk see also http://www.bigstockphoto.com/account...fid=m2URATYch5 http://www.redbubble.com/people/simonsphotography

21st August 2005, 07:20 AM	(permalink)
Thunderchild Experienced Member	well as for the professional way i have no idea and not having an osciliscope because of its cost i would resort to a simple homemade probe but the method is up to u perhaps u should try and find a good book on the subject if u want to go into it on that large a scale as i suppose u would have to know the various signal levels that each family of chips use. __________________ I AM the exeption that disproves the rule in many ways but the rules still apply (unfortunately) my site:www.simons-photography.com http://rushdenrotaract.org.uk see also http://www.bigstockphoto.com/account...fid=m2URATYch5 http://www.redbubble.com/people/simonsphotography

21st August 2005, 06:21 AM	(permalink)
walters Banned	For Testing Gates in a Circuit do i inject a HIGH or LOW signal to the input of the GATE and use the logic probe on the output of the gate ? with the truth table like to me ?

21st August 2005, 06:37 AM	(permalink)
walters Banned	THanks for the information How can i do in-circuit testing for digital components? Gates troubleshooting in-circuit testing? Clock troubleshooting in-circuit testing? registers troubleshooting in circuit testing? How do i test and troubleshoot decorders or encoders?

21st August 2005, 06:59 AM	(permalink)
walters Banned	Well im talking more about a product for company's that make a board or circuit thats digital and knowing how to troubleshoot it and how to start testing digital componects that my problem of knowing digital troubleshooting skills what should i know? and how to do this?

21st August 2005, 07:31 AM	(permalink)
walters Banned	Yes whats the professional way for digital troubleshooting ?

21st August 2005, 07:39 AM	(permalink)
Thunderchild Experienced Member	there is no specific method i suppose it depends on the situation what u prefer and what u have at hand i mean a multimeter can be used if nothing else is at hand. i think the most professional instrument available i cannot remember the name of but is is like an osciliscope and can veiw in some up to like 16 signal simutainesly. basical i suppose what makes a professional is knowing how to deal with each situation. some companies even design for their products custom circuit testers that have a board with dozens of probes sicking up and the faulty circuit is placed on top and the whole board is analysed at once but this is a computerised machine and is specific for each board and is only feasable on a large scale. it just depends on what u r working on and what u have available. __________________ I AM the exeption that disproves the rule in many ways but the rules still apply (unfortunately) my site:www.simons-photography.com http://rushdenrotaract.org.uk see also http://www.bigstockphoto.com/account...fid=m2URATYch5 http://www.redbubble.com/people/simonsphotography

21st August 2005, 07:45 AM	(permalink)
walters Banned	How would u test digital components like registers,encoders,decorders, decimal to hexadecimal, gates?

21st August 2005, 07:50 AM	(permalink)
Thunderchild Experienced Member	with the digital oscilisope thing and a signal injector. connect the inputs of the instrument to the outputs in quetion and probe with the injector and verify the results. if u r dealing with encoders and decoders then i think u have like 8 inputs ? for the different addresses so perhaps something like a word generator is necedary and can be wasily built it is just as multy out put signal injector __________________ I AM the exeption that disproves the rule in many ways but the rules still apply (unfortunately) my site:www.simons-photography.com http://rushdenrotaract.org.uk see also http://www.bigstockphoto.com/account...fid=m2URATYch5 http://www.redbubble.com/people/simonsphotography

21st August 2005, 07:55 AM	(permalink)
walters Banned	But how do i know if the encorders and decorders are working right? I got the oscilloscope on inputs and the outputs Yes the encoders have 8 inputs and the decoders have 8 outputs How do i test the Encoder and decoder Addresses? with a probe or oscilloscope what do Encoder and decoder Addresses look like on a oscilloscope ? Are Encoder and decoder Addresses voltages? or a waveform?

21st August 2005, 08:05 AM	(permalink)
Thunderchild Experienced Member	digital 1 is normally VCC and digital 0 0volts so onthe oscilicope singal tracer or what ever u use u will see 0 or VCC (or there abouts as theory is never practice even in digital stuff) so say u have the encoder. this has for example 3 address inputs 2 to the power of 3 is eight therefor u can have 8 inputs being encoded into 1 output when u input address 0 (000) input 0 is sent to the output when u input ADD 1 (001) in 1 goes to output and so on until input 7 and add 7 (111) so u have to produce all the 8 addresses (000 - 111) and verify that the signals uinput to the relevant input are coming from the output. basically just get the blasted truth table and create urself all the states on it. u also have to understand what the chip does proporly to know what is going on and be able to understand the data sheet as it may make a very breif explanation of the chip and it's truth table. __________________ I AM the exeption that disproves the rule in many ways but the rules still apply (unfortunately) my site:www.simons-photography.com http://rushdenrotaract.org.uk see also http://www.bigstockphoto.com/account...fid=m2URATYch5 http://www.redbubble.com/people/simonsphotography

21st August 2005, 08:12 AM	(permalink)
walters Banned	Is there a easier way to do this without truth tables testing digital componects checking the inputs and outputs the truth tables can take along time to check all the High and low states don't you think thats really hard to track a digital componect down thats not working right i would have a bunch of truth tables then?

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