Thank you very much for your kind replies. I am just a retired pensioner trying to learn electronics to keep my mind active and hopefully repair instead of replace any electronics appliances I have at home also it fascinates me. Once again thank you for the videos they help me enormously.
Nice job, a lot of people don't seem to realise nowadays just how much fault finding can be done with a good multimeter. When I first started servicing Microcomputers, a Multimeter and Logic probe was all we were given . Scopes were non existent in most workshops and if there was one, only the workshop manager got to use it. The multimeter was king ☺. Keep up the good work
I hope you don't mind the question; this is great for finding shorts on IC's, is there any information that can be gleaned from the data gathered from putting the black to ground and recording the red probe data. I have been experimenting with this. Thanks for your time.
Yes you would still see a short circuit regardless of lead polarity. I just like to see a diode voltage drop. Only personal preference. I also take the red lead to Vcc and probe the pins with the black lead to search for short circuits up to Vcc. It does happen. One thing to be careful of though. On this newer lower voltage technology. Say a Vcc of 3.3Vdc and 0.7Vdc. The voltage diode drops appear to be short circuits. When actually they are not. I have caught myself going down that never ending path of frustration. HaHa...
I do electronics as a hobby. I have a good knowledge on most components, by testing them, but ICs always bring me to a halt. Your video has helped me a lot and also saved me some money.
GND pin is connected with all the anodes of the diodes from pin 11 to pin 18 and to test a diode reading you have to put the red lead on the anode and the black lead on the cathode
@@knightwar3This is correct, about testing the diodes of this specific IC, nevertheless we test in this way all the terminals of any IC, no matter if they are analog or digital. This test gives us a "leakage-like" picture (in millivolts DC) of any specific pin of any IC. This test is the "half" part of the V/I signature analysis being done by using an oscilloscope and an "octopus" external circuit, using the oscilloscope in X-Y mode. Practically, it's a dual polarity test of the same kind as with the multimeter, but far more superior than that...
You need to search how a diode works, I will give you a reference on what happen when you connect the probes in both ways but please search for more after this: When you comnect a positive pin to the negative pin of the diode, and rhe negative pin to the positive, the deplotion zone gets bigger so the resistence is higher When you apply negative to negative and positive to positive the deplition zone shrink, these being said the diode alows the curent to flow in one direction.
Hello and thank you for stopping by. I have used this method of hunting for shorted integrated circuits all the time on circuit boards. Watch my video on repairing a Fanuc I/O Board of short circuits in this link here. ua-cam.com/video/Dx1emYj-rcY/v-deo.html
thanks for a very nice video. would this method work with the IC soldered on the board? I feel the surrounding circuit might create all sorts of misreads on the chip I want to test.
ua-cam.com/video/Dx1emYj-rcY/v-deo.html Click on the above link of myself hunting for short circuits of integrated circuits soldered to an Input / Output Board.
Of course as you are correct you can have misreads on certain boards. Especially from Vcc to Gnd on modern motherboards. Where the Vcc to Gnd is +3Vdc, +1.5Vdc, and +0.7Vdc. On these motherboards to Vcc to Gnd voltage diode drop is unbelievably small. They are so small that I don't even bother testing for short circuits. But then most motherboards that do not boot up is caused by cheap electrolytic capacitors. You can visually see the tops of the electrolytic capacitors have bulged out.
Rule of thumb for your survival. Do not ship out to another planet or solar system on cheap electrolytic capacitors. You will not make it back to Earth. HaHa...
Hello Beheaded Guitarist. I set my meter to diode test mode. I like fiddles, banjos, and dulcimers. But my Father many years ago taught most of our music around the guitar. We have to have music in our lives don't we? Great question, I hope my answer cleared up this procedure.
I don't find this test reliable. I've tried several IC's, some new, and all have one or more pins out of the "good" range. (.350, .840, etc.). They can't all be bad, can they?
The test is reliable indeed, but it has a comparative character, which means that you should always compare the voltages you find from each pin of a known good chip (used as a reference) to each (same each time) pin of the suspected one I.e. pin 1 of reference IC to pin 1 of the suspected one, etc. There should be no voltage diffefence between the two (identical) pins, or very-very little one (:negligible).
Little known trap ... The Fluke 87 were the electrical multimeters Not electronic multimeters & have different characteristics IE for the diode test it actually gives out a higher voltage than you expect from an electronics DMM and can damage ICs, especially of the 1.8v CMOS variety. Checked with Fluke personally after an issue on a production line. 👍
Interesting...This old coot only works on IC's from the 70's, 80's, 90' 00' and so on. I learned today from you. That there are CMOS versions of IC that are powered up from 1.8Vdc. What was the issue that you had on your production line. Just so we don't make any mistakes ourselves. Thanks for informing the rest of us :)
@@PeepawMcDonald If memory serves correct as it was about ten years ago a chap was using that Meter on the diode test to check a product when it came back for service/ calibration. After some tweaking and firmware updates they would then proceed to do some final checks across some test points on diode test, which was then damaging the 1.8v CMOS ICs. Yet it had been done this way for years ... We only realised what was going on when the meter under suspicion had been taken off the shelf where it was just used as a voltmeter as the usual DMM had gone faulty. we compared the output of one meter on diode test to the 87 an then got in touch with fluke who confirmed our suspicions, as I'd never heard of an Electricians DMM untill that point. 👍
@@TG-ok4ty Yea it's a good ear mark if you hear people say things like that or don't buy a meter with current measurements that they just don't know as much as they think they do. Cowboys are everywhere every man and his dog can fix computers or TVs etc but they come unstuck when it's a difficult fault do silly things and get caught out. 👍
Hello Mr. Warfield. I can remember some years ago being turned around and confused about the labels given to some pins of integrated circuits. Don't worry about being new to electronics. To this very day... To this very minute I learn something new about electronics.
The term Vs stands for Voltage Source. It is the voltage applied to a circuit from a power supply circuit. The term Vcc stands for Voltage common collector. This is the positive power supply connection to TTL (Transistor Transistor Logic) integrated circuits. Or the positive power supply connection to an NPN transistor amplifier circuit. Both are only terms to indicate a positive power supply connection to the circuit.
The voltage Vs (with respect to ground) can be any voltage. It depends on the person drawing the schematic and of course the actual power supply voltage required by the circuit. Usually Vcc is +5VDC. But here recently, we have seen micro-controller and micro-processor integrated circuits with Vcc as low as 3.3Vdc and 1.5Vdc
So Vs and Vcc are the power supply connections to the circuits. I hope this helps in you journey of exploring electronic circuits. Stop by anytime. You are always welcome. I hope that you and your family are doing well.
Peepaw, you are THE BEST! Thank you so much for replying, I really am trying to learn, and your videos are a great part of that. Thank you for your explanations, I really do appreciate it. I am not in this field, at all, I'm just a guy trying to fix electronic stuff 'round the house. You don't talk down to us, like I feel, a lot of tutorial videos do - like a bunch of experts making videos, for other experts. The jargon is daunting enough on its own... Hey, again sincerly, thank you kindly Peepaw. Cheers!
Hello Mr Young. The CA3086 is four NPN transistors in one integrated circuit package. There is no single ground as you would usually have. You must test each NPN transistor as if were testing one NPN transistor with your digital multimeter. Nice question. Thank you very much for stopping by. If you wish you can find datasheets at this website www.datasheetcatalog.com/
Well-done and informative vid. Ditch the "music"...it's just distracting and not needed. You might mention that you need the data sheet for each chip to know which pin is gnd.
@@PeepawMcDonald How can I argue with that? Also, does this test work for all ic's? My 555's 5 and 6 pins show way below the diode range. Please advise.
I would find a datasheet of the integrated circuit on the internet. Then I would build the test circuit of the integrated circuit on a breadboard. Then dynamically test the integrated circuit using the datasheet. If the integrated circuit passes the dynamic test in accordance with the datasheet. It is good. Great question. Thank you for stopping by for a visit.
This has been the best video explaining how to do this! I am working on a guitar pedal and because of your video, I was able to figure out that it had a bad IC. Thank you so much for the help!
Hello Bruce, usually most TTL and CMOS IC's ground pin is pin 7 or pin 8. For 14Pin and 16Pin IC's. If it is unclear to me which pin is ground. I will hunt for a datasheet on the internet. My favorite website to find datasheets is datasheetcatalog.com I hope this helps you :)
Thank you McDonald for such a detailed video on testing ICs with a digital multimeter. Its very fascinating as I like to work on electronic components. Initially I had put my meter on continuity mode and was testing but was getting no reading. But after seeing your video put the meter on diode mode and get good readings. Thanks a lot. Have subscribed your channel for more.
Hello Sir, truely I am not sure. For the last thirty years I have been using my trusty digital multimeter from Fluke. When I was in the USAF we had the PSM-6 volt - resistance meter. But back then when I was troubleshooting, I was only chasing broke wire connections. Haha. If I had my old PSM-6, I could test this method of troubleshooting integrated circuits for short circuits.
Now if you get frisky, set your meter for the highest resistance range. Before searching for short circuits. The lower ranges of resistance measurements output more current that may damage the integrated circuit.
This is great, thank you! What if the meter reads nothing on one or more of the pins? Most of the ICs I've tested are in the .615 range meaning good or 0.00 to 0.51 indicating a major drop, meaning a short. But some pins do nothing, just ".OL" on the meter? Does this mean something? Also several ICs in a row on a board have one pin that reads exactly the same, .194 Either this .194 pin is a normal reading over 10 to 12 chips or all of them are bad. I'm thinking they're fine because so many of them test the same on that one leg maybe you could shed some light on that? Thanks so much!
Nice clear video, but why red on ground also no one ever seems to explain the reading of the different voltages this leaves the viewer or student very frustrated as we cannot correlate the readings only 0.001 or very low means a short to ground what about numbers from 12 to 600 please explain, many thanks for the video.
Hello Sir, thank you for watching one of my videos. Please don't be frustrated. This is only a tool. And a tool to help quickly troubleshoot electronic circuits. Like any tool, some get used more than others.
As far as the different diode voltage drop values that you see. Let us take one integrated circuit. The voltage drops for the inputs should be fairly close in value. The same for all the outputs. So If I have five outputs that measure close to 0.640V, and then one that measures 0.024V, I would call the odd one out the bad one.
We are comparing good measurements to bad measurements. As far as seeing different diode voltage drop values. These are semiconductor devices. If we lived in the perfect world they would all have the same diode drop.
And for the red lead on ground, and the black lead on all the other pins. As an experiment, try putting the black lead on ground, and the red lead on all the other pins. Do you get something higher than a diode drop? Let us know what you derive from your experiments. And try this experiment. Place your black lead on Vcc, and the red lead on all the other pins. Do you get good diode drops?
I was taught this troubleshooting tool by Professor Charles Phillips. I don't know if he is still alive. That was many years ago. We lost track of each other. Take a look at the datasheets for the integrated circuits that you are working on. You will see why this method of troubleshooting for short circuits works.
ua-cam.com/video/Dx1emYj-rcY/v-deo.html Click on the above link of myself hunting for short circuits of integrated circuits soldered to an Input / Output Board. Thank you so much for asking. I hope you are doing well.
What does it mean, when the reading you get on your meter is Over Limit, is that a short or something worse? Because that's what I'm getting, when testing a few 74LS90 ICs. Please let me know. Thank you kindly
Hello Mr Warfield. I hope that all is well with you and your family. The "OL" on the DMM is not fatal. I see this on my Fluke digital multimeter when I am looking at an integrated circuit pin that has no connection (NC). On the 74LS90, pins 4 and 13 are labeled as no connection (NC). I hope this helps. Thank you very much for watching one of my videos. And I thank you for stopping by.
Thank you so much for replying. Your info is really helping me. I do as much as I can, on my own but sometimes, all this electronic stuff can becomes quite confusing for a novice, like me. Nice to have someone in my corner. Hey, all the best to you and your loved ones. Lead on, good sir!
Awesome! You're a great teacher! Thank you for your thoroughness!
Thank you very much for your kind replies. I am just a retired pensioner trying to learn electronics to keep my mind active and hopefully repair instead of replace any electronics appliances I have at home also it fascinates me. Once again thank you for the videos they help me enormously.
Thanks for giving good lesson. About how to check. ICs
Nice job, a lot of people don't seem to realise nowadays just how much fault finding can be done with a good multimeter. When I first started servicing Microcomputers, a Multimeter and Logic probe was all we were given . Scopes were non existent in most workshops and if there was one, only the workshop manager got to use it. The multimeter was king ☺. Keep up the good work
sir can we check logic ics , also like this , in diode mode
I hope you don't mind the question; this is great for finding shorts on IC's, is there any information that can be gleaned from the data gathered from putting the black to ground and recording the red probe data. I have been experimenting with this. Thanks for your time.
Yes you would still see a short circuit regardless of lead polarity. I just like to see a diode voltage drop. Only personal preference. I also take the red lead to Vcc and probe the pins with the black lead to search for short circuits up to Vcc. It does happen. One thing to be careful of though. On this newer lower voltage technology. Say a Vcc of 3.3Vdc and 0.7Vdc. The voltage diode drops appear to be short circuits. When actually they are not. I have caught myself going down that never ending path of frustration. HaHa...
Thank you! 👍
Very nicely done. I was looking for a nice video to feed my morning hunger.
I do electronics as a hobby. I have a good knowledge on most components, by testing them, but ICs always bring me to a halt. Your video has helped me a lot and also saved me some money.
Can this method be used to test all ICs?
Thank you Mr. Mcdonald, great lesson.
Why red on the ground and not black on ground? That is confusing to me, I am sure there is a good reason though
You're not the only one, I'm thinking the same.
GND pin is connected with all the anodes of the diodes from pin 11 to pin 18 and to test a diode reading you have to put the red lead on the anode and the black lead on the cathode
Because the current doesn't flow that way.
@@knightwar3This is correct, about testing the diodes of this specific IC, nevertheless we test in this way all the terminals of any IC, no matter if they are analog or digital. This test gives us a "leakage-like" picture (in millivolts DC) of any specific pin of any IC. This test is the "half" part of the V/I signature analysis being done by using an oscilloscope and an "octopus" external circuit, using the oscilloscope in X-Y mode. Practically, it's a dual polarity test of the same kind as with the multimeter, but far more superior than that...
You need to search how a diode works, I will give you a reference on what happen when you connect the probes in both ways but please search for more after this:
When you comnect a positive pin to the negative pin of the diode, and rhe negative pin to the positive, the deplotion zone gets bigger so the resistence is higher
When you apply negative to negative and positive to positive the deplition zone shrink, these being said the diode alows the curent to flow in one direction.
Excellent video! Can this test be performed with the TTL chip still connected on the circuit board?
Hello and thank you for stopping by. I have used this method of hunting for shorted integrated circuits all the time on circuit boards. Watch my video on repairing a Fanuc I/O Board of short circuits in this link here. ua-cam.com/video/Dx1emYj-rcY/v-deo.html
Is that a yes?
Great job Sir 👏 Than you v much
thanks for a very nice video. would this method work with the IC soldered on the board? I feel the surrounding circuit might create all sorts of misreads on the chip I want to test.
ua-cam.com/video/Dx1emYj-rcY/v-deo.html
Click on the above link of myself hunting for short circuits of integrated circuits soldered to an Input / Output Board.
Of course as you are correct you can have misreads on certain boards. Especially from Vcc to Gnd on modern motherboards. Where the Vcc to Gnd is +3Vdc, +1.5Vdc, and +0.7Vdc. On these motherboards to Vcc to Gnd voltage diode drop is unbelievably small. They are so small that I don't even bother testing for short circuits. But then most motherboards that do not boot up is caused by cheap electrolytic capacitors. You can visually see the tops of the electrolytic capacitors have bulged out.
Rule of thumb for your survival. Do not ship out to another planet or solar system on cheap electrolytic capacitors. You will not make it back to Earth. HaHa...
what if black probe placed on ground side?
How did you set the multimeter for the IC test?
Hello Beheaded Guitarist. I set my meter to diode test mode. I like fiddles, banjos, and dulcimers. But my Father many years ago taught most of our music around the guitar. We have to have music in our lives don't we? Great question, I hope my answer cleared up this procedure.
@@PeepawMcDonald thanks a lot
what is the different of TTL and CMOS ICs... thanks
Hye.. is the SAME with all types of IC ? Means.. this step .
Does this work for checking other i.c's such as the 555 timer, the op-amp and digital i.c's?
Yes!
Your work is awesome and a complete answer to the problem I have on testing ics
I don't find this test reliable. I've tried several IC's, some new, and all have one or more pins out of the "good" range. (.350, .840, etc.). They can't all be bad, can they?
The test is reliable indeed, but it has a comparative character, which means that you should always compare the voltages you find from each pin of a known good chip (used as a reference) to each (same each time) pin of the suspected one I.e. pin 1 of reference IC to pin 1 of the suspected one, etc. There should be no voltage diffefence between the two (identical) pins, or very-very little one (:negligible).
Another great video, I have learned a lot from your videos.
Little known trap ...
The Fluke 87 were the electrical multimeters Not electronic multimeters & have different characteristics IE for the diode test it actually gives out a higher voltage than you expect from an electronics DMM and can damage ICs, especially of the 1.8v CMOS variety. Checked with Fluke personally after an issue on a production line. 👍
Interesting...This old coot only works on IC's from the 70's, 80's, 90' 00' and so on. I learned today from you. That there are CMOS versions of IC that are powered up from 1.8Vdc. What was the issue that you had on your production line. Just so we don't make any mistakes ourselves. Thanks for informing the rest of us :)
@@PeepawMcDonald If memory serves correct as it was about ten years ago a chap was using that Meter on the diode test to check a product when it came back for service/ calibration. After some tweaking and firmware updates they would then proceed to do some final checks across some test points on diode test, which was then damaging the 1.8v CMOS ICs. Yet it had been done this way for years ... We only realised what was going on when the meter under suspicion had been taken off the shelf where it was just used as a voltmeter as the usual DMM had gone faulty. we compared the output of one meter on diode test to the 87 an then got in touch with fluke who confirmed our suspicions, as I'd never heard of an Electricians DMM untill that point. 👍
I had a friend that used to repair high dollar test equipment. He said never use the diode setting!
@@TG-ok4ty Yea it's a good ear mark if you hear people say things like that or don't buy a meter with current measurements that they just don't know as much as they think they do. Cowboys are everywhere every man and his dog can fix computers or TVs etc but they come unstuck when it's a difficult fault do silly things and get caught out. 👍
Can this be tested in circuit with this method?
Thanks bro for ur knowledge! Very helpful!
Complete NOOB here. What does VS stand for, voltage supply, I'm guessing? And what is VCC? Bear with me, I'm learning a lot, with your videos. Cheers!
Hello Mr. Warfield. I can remember some years ago being turned around and confused about the labels given to some pins of integrated circuits. Don't worry about being new to electronics. To this very day... To this very minute I learn something new about electronics.
The term Vs stands for Voltage Source. It is the voltage applied to a circuit from a power supply circuit. The term Vcc stands for Voltage common collector. This is the positive power supply connection to TTL (Transistor Transistor Logic) integrated circuits. Or the positive power supply connection to an NPN transistor amplifier circuit. Both are only terms to indicate a positive power supply connection to the circuit.
The voltage Vs (with respect to ground) can be any voltage. It depends on the person drawing the schematic and of course the actual power supply voltage required by the circuit. Usually Vcc is +5VDC. But here recently, we have seen micro-controller and micro-processor integrated circuits with Vcc as low as 3.3Vdc and 1.5Vdc
So Vs and Vcc are the power supply connections to the circuits. I hope this helps in you journey of exploring electronic circuits. Stop by anytime. You are always welcome. I hope that you and your family are doing well.
Peepaw, you are THE BEST! Thank you so much for replying, I really am trying to learn, and your videos are a great part of that. Thank you for your explanations, I really do appreciate it. I am not in this field, at all, I'm just a guy trying to fix electronic stuff 'round the house. You don't talk down to us, like I feel, a lot of tutorial videos do - like a bunch of experts making videos, for other experts. The jargon is daunting enough on its own... Hey, again sincerly, thank you kindly Peepaw. Cheers!
Thank you for your sharing god blessed
How do I know what pin is ground? I am testing a CA3086
Hello Mr Young. The CA3086 is four NPN transistors in one integrated circuit package. There is no single ground as you would usually have. You must test each NPN transistor as if were testing one NPN transistor with your digital multimeter. Nice question. Thank you very much for stopping by. If you wish you can find datasheets at this website www.datasheetcatalog.com/
Well-done and informative vid. Ditch the "music"...it's just distracting and not needed. You might mention that you need the data sheet for each chip to know which pin is gnd.
The music stays. It saved my life...
@@PeepawMcDonald How can I argue with that? Also, does this test work for all ic's? My 555's 5 and 6 pins show way below the diode range. Please advise.
How to test sram chip?
what if the ic has no diodes or it has diodes but thy are not shorted ? how to know if the ic is working for example how would you test a fan7382 ?
I would find a datasheet of the integrated circuit on the internet. Then I would build the test circuit of the integrated circuit on a breadboard. Then dynamically test the integrated circuit using the datasheet. If the integrated circuit passes the dynamic test in accordance with the datasheet. It is good. Great question. Thank you for stopping by for a visit.
@@PeepawMcDonald thank you i was hoping in a quicker handy solution like you did in your video :-)
This has been the best video explaining how to do this! I am working on a guitar pedal and because of your video, I was able to figure out that it had a bad IC. Thank you so much for the help!
So usually when there is a short in the ic multiple pins go to ground rather than just one pin? Is that true ?
Yes, most times that is true. But as in life, this can also be false. HaHa. Thank you so much for stopping by and watching one of my videos.
@@PeepawMcDonald 😄
Can these chips be tested this way while still in circuit?
Yes, see the reference at 10.14 of the video.
What did he call pin 9 I didn't quite get the name
Vs pin...
does this method of troubleshooting the same for Flat ICs ? example of TQFP
How do you know what pin is the Ground
Hello Bruce, usually most TTL and CMOS IC's ground pin is pin 7 or pin 8. For 14Pin and 16Pin IC's. If it is unclear to me which pin is ground. I will hunt for a datasheet on the internet. My favorite website to find datasheets is datasheetcatalog.com
I hope this helps you :)
@@PeepawMcDonald thank you very much.
👍🏿👍🏿👍🏿
Hi!
I'm using this technique from some time now. It works also on very complex ic's in mobiles. But you have always to keep in mind the circuitry
hy
THANK-YOU VERY MUCH MATE !!...YOU SOUND LIKE KENNY ROGERS !!
How to check 8 bit shift register? Viz. 74HC595.
Nice tutorial, I have mn3008 with 4 pins, just want to know if the same logic of testing applies.
Just what I have been looking for. Thank you very much for this video!
❤
Thank you McDonald for such a detailed video on testing ICs with a digital multimeter. Its very fascinating as I like to work on electronic components. Initially I had put my meter on continuity mode and was testing but was getting no reading. But after seeing your video put the meter on diode mode and get good readings. Thanks a lot. Have subscribed your channel for more.
Nice video man, Can you do this "in-circuit":? or do we have to remove the chip?
Check 10:14 where it says on the screen 'yes' to your question.
Thank you very much sir for the lesson this will be very helpful
is this suitable for all kinds of ics? and why do we put the red lead on ground?
Do you have a video on how to perform a bench test on a TNY278PN power integration chip with a multimeter?
Thanks a lot, now I'll test my inboards circuits and find the culprit :)
Hi sir hope you all the best .i just want to ask you .can digitals ic checked by multy tester?
Hello Sir, truely I am not sure. For the last thirty years I have been using my trusty digital multimeter from Fluke. When I was in the USAF we had the PSM-6 volt - resistance meter. But back then when I was troubleshooting, I was only chasing broke wire connections. Haha. If I had my old PSM-6, I could test this method of troubleshooting integrated circuits for short circuits.
Now if you get frisky, set your meter for the highest resistance range. Before searching for short circuits. The lower ranges of resistance measurements output more current that may damage the integrated circuit.
Please sir, let us know how it goes. I miss my old PSM-6
Nice info, thanks :)
Hi! I would like to know how to test other semiconductor such as diode, capacitor....
This is great, thank you! What if the meter reads nothing on one or more of the pins? Most of the ICs I've tested are in the .615 range meaning good or 0.00 to 0.51 indicating a major drop, meaning a short. But some pins do nothing, just ".OL" on the meter? Does this mean something? Also several ICs in a row on a board have one pin that reads exactly the same, .194
Either this .194 pin is a normal reading over 10 to 12 chips or all of them are bad. I'm thinking they're fine because so many of them test the same on that one leg maybe you could shed some light on that? Thanks so much!
OL means it's not connected to anything (Open Loop).
It is not a short and you'll see that on a IC schematic diagram it's written NC (No connection).
Thanks for the video
Nice clear video, but why red on ground also no one ever seems to explain the reading of the different voltages this leaves the viewer or student very frustrated as we cannot correlate the readings only 0.001 or very low means a short to ground what about numbers from 12 to 600 please explain, many thanks for the video.
Hello Sir, thank you for watching one of my videos. Please don't be frustrated. This is only a tool. And a tool to help quickly troubleshoot electronic circuits. Like any tool, some get used more than others.
As far as the different diode voltage drop values that you see. Let us take one integrated circuit. The voltage drops for the inputs should be fairly close in value. The same for all the outputs. So If I have five outputs that measure close to 0.640V, and then one that measures 0.024V, I would call the odd one out the bad one.
We are comparing good measurements to bad measurements. As far as seeing different diode voltage drop values. These are semiconductor devices. If we lived in the perfect world they would all have the same diode drop.
And for the red lead on ground, and the black lead on all the other pins. As an experiment, try putting the black lead on ground, and the red lead on all the other pins. Do you get something higher than a diode drop? Let us know what you derive from your experiments. And try this experiment. Place your black lead on Vcc, and the red lead on all the other pins. Do you get good diode drops?
I was taught this troubleshooting tool by Professor Charles Phillips. I don't know if he is still alive. That was many years ago. We lost track of each other. Take a look at the datasheets for the integrated circuits that you are working on. You will see why this method of troubleshooting for short circuits works.
I really like this method
Thanks man!! This is another easy way to check ic. Very helpfull.
Thanks my brother
Can it be done without removing from the PCB?
ua-cam.com/video/Dx1emYj-rcY/v-deo.html
Click on the above link of myself hunting for short circuits of integrated circuits soldered to an Input / Output Board. Thank you so much for asking. I hope you are doing well.
Nice explanation
Thank you
Thank you so much sir.
Good checking thank you
Good jop
Finding shotr curcuit continuty mode
?
Can we check all IC in this way ?
Yes!
👍👍👍
What does it mean, when the reading you get on your meter is Over Limit, is that a short or something worse? Because that's what I'm getting, when testing a few 74LS90 ICs. Please let me know. Thank you kindly
Hello Mr Warfield. I hope that all is well with you and your family. The "OL" on the DMM is not fatal. I see this on my Fluke digital multimeter when I am looking at an integrated circuit pin that has no connection (NC). On the 74LS90, pins 4 and 13 are labeled as no connection (NC). I hope this helps. Thank you very much for watching one of my videos. And I thank you for stopping by.
Thank you so much for replying. Your info is really helping me. I do as much as I can, on my own but sometimes, all this electronic stuff can becomes quite confusing for a novice, like me. Nice to have someone in my corner. Hey, all the best to you and your loved ones. Lead on, good sir!