Playing with IC’s: Part 3
In Part 2- https://www.jestineyong.com/playing-with-ics-part-2/, I thought I had received some damaged IC’s because they were not working right. Then our friend Steven Neo suggested that I had the inductor in the circuit wrong. Of course – that is probably the problem! I can’t believe I didn’t notice my mistake, but I am glad Steven did. As it turns out, Steven is correct.
So I rearranged the circuit on the breadboard while also bringing the components in closer to the IC. Eureka; the IC is working properly now!
Here is the Datasheet for the IC #FR9882: http://pdf.datasheetarchive.com/indexerfiles/Datasheets-AS2/DSAAXSA0008861.pdf
As you can see in the next few photos, the IC is outputting acceptable voltage at different input voltages – problem solved! This IC is working properly even on my breadboard! I decided not to build the circuit on a PCB, at least for now.
The IC is holding strong at an input of 8.16V.
I checked two more IC’s and they checked out good as the first one. I know for sure that one of them is bad, but I’m not going to show everyone of the IC’s in this article. I will find the bad IC’s later and throw them away. Testing three of the IC’s is enough to prove that my circuit was the previous problem, and not the IC’s being shipped to me without ESD protection.
The IC is still holding strong at 12.07V input!
Here is a snapshot of one of the IC’s waveform. It has a frequency of about 315 KHz, which is in tolerance for the IC.
There is a secret I learned on a YouTube channel that I’m subscribed to. The channel is named, “Mr. Carlson’s Lab”. Mr. Carlson is very knowledgeable and has many great electronics videos. I advise everyone to visit his channel and subscribe. https://www.youtube.com/user/MrCarlsonsLab
I have always heard that “non-polarized” capacitors are non-polarized, haven’t you? Well, as I’m about to show you, that is not entirely accurate…
In the Poly or Mylar type capacitors, one of the leads will be connected to the outside foil end (Band End), or also called the (shielded end), or (foiled end), of the inside of the cap. The lead that is connected to the band end of the cap should be connected to ground, or the lower impedance of the circuit, depending on the circuit the cap is in. If the band end is connected to the higher impedance in the circuit, then it will emit RFI that can couple into surrounding circuits! It can also give you a hum or noise in amplifiers! If you have replaced caps in radios or amplifiers and had noise that should not be there, then you may have installed the “non-polarized” capacitors in backwards!
In the following photos I will show you how to check your caps so that you will know which end is the band end (shielded end), and install your caps correctly! Of course, RFI doesn’t make much difference in my little test circuit here; but it can make a lot of difference in other circuits!
In the above photo you can see me holding the 10nF cap in the photo above this one in my fingers (without touching the leads). My body is acting as an antenna. I have a coax cable connected to my scope on channel 1. The scope is set to DC 2mV/div at 10ms/div with the 20MHz BW Limit on. I previously checked the cap and marked the band end lead with a red marker. The positive grabber on my coax is connected to the band end of the cap, and you can see the size of the waveform. So the waveform should be smaller when the negative or ground lead is connected to the band end because my body, acting like an antenna, will have less effect than when I’m holding the cap this way because the band end of the cap will help shield the current passing through the cap.
So when you have the smallest waveform, the lead that the ground wire of your coax is connected to, is the band end, or shielded end of the capacitor!
You can see in the above photo that the waveform is smaller now that I have the coax connected properly; with the ground on the band end lead of the cap. Be careful not to touch the leads while holding the capacitor.
I also noticed that resting my elbows on my grounded anti-static mat on my table affected the readings, so be careful. It is also harder to tell the difference on the real small caps.
The waveform is larger in this photo indicating that the ground (black) grabber is not connected to the band end of the capacitor.
On this second capacitor in the two photos above, you can clearly see that the bottom lead is connected to the band end of the cap because when the ground lead of the coax is connected to it, the waveform is smaller.
Now you can go fix problems that others could not fix! And you can install your caps correctly in your own devices so they operate more efficiently with less RFI emission!
Also be careful because some caps will have a mark on them, but it will NOT necessarily be the band end! So you can check them yourself now to be sure!
And many caps in the same batch will have the numbers stamped on different sides of the cap, so that if the band end of one cap is on the right side when reading the information on the cap, another one may have the band end on the left side while looking at it. So check them yourself to be sure. Here is a link to Mr. Carlson’s video about this secret: https://youtu.be/BnR_DLd1PDI
New breadboard with the inductor in properly, and the components moved in closer to the IC.
Notice the arrow in the above photo? I accidently had the cathode of the 22uF electrolytic cap (C2) in the positive rail instead of the negative rail. There is no power on the positive rail, but it rendered the cap useless for the circuit. That is why I was only getting nearly 3.2V output from the IC, and a distorted waveform. Once I corrected that mistake, the IC’s performed beautifully on my breadboard! No need for building the circuit on a PCB for testing now!
Another look at the breadboard circuit.
Here is another look at the breadboards.
Here’s a sneak peek into my new BK Precision 114a VOM. It is a quality meter! Praise the Lord God – I am very fortunate to buy it at such a great price! It also has a good ceramic fuse.
The above photo is an early one with the cathode of the 22uF cap (C2) in the positive rail instead of the negative rail where it belongs. You can see the distorted waveform and the lower output at 3.143V.
I’m almost sad that I am finished with this article. Oh well, time to move on. I hope you guys like the article. I would like to give special thanks to Mr. Yong for providing this website for us to learn, share, and experiment. Also, to Mr. Carlson’s Lab for his brilliant videos and revealing of great electronics secrets. And thanks also to Steven Neo who spotted my mistake and made for a swifter end to the article. Thanks to all who comment and support our articles.
Robert Calk is a hobbyist from the USA that loves learning electronics and device repair.
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Albert
June 3, 2015 at 1:59 am
I always said it. You're a professional. Nice Tektronix oscilloscope. Yes sir ! 300MHz ?? WOW!!
My question Robert.. did you also fix your Router Modem now, or what had a bad FR9882 step down controller in it if I'm correct? Or was that not the reason you started this 3 article serie at first?
And thanks for the non-polarized capacitor info.
It is always better to prevent RFI than to eliminate it.
Albert.
Robert Calk
June 3, 2015 at 3:53 pm
Thanks Albert, I'm glad you liked the article. My scope is a 350MHz.
I stripped the router of components for parts - the boys didn't want to wait. They got a new router so they could hurry up and get back to playing video games.
Yes, in the RF game every little bit counts.
Albert
June 8, 2015 at 2:17 am
On 11 June I hope my Tek 2465A will arrive, and pray it won't have too many faults or even unrepairable errors.
All my Holiday money is in this 350MHz device. All for the Good of our Electronics Hobby.
The 2500Volt China Insultation tester was a bit of a disappointment. Any load like just a simple Elco and the HV output quits working immediatly. Or the Tester reacts with erratic behavior. 1.3mA is just too little power to be able to test the PowerSupply stuff! So I guess only little Capacitors are useable as testobjects. But strangely you can't find anything specific in the accompanied manual other then the 1.3 mA Max Load value.
But I take it that you already estabalished this fact by using your AR Insultation Tester? Elco's like say 100uF 400V are just impossible to test.
Greetings.
Albert.
Albert
June 8, 2015 at 4:59 am
PS: I meant to write Established and AR907A Insulation Tester. But not Unsultation Tester of Course although these tester are not worth buying with this poor performance !
A 1.3mA current at 2500 Volt is not the problem. But the Real problem is the fact that the AR Tester even needs minutes to build up a 2500V or lesser charge at 1.3mA if it manages that at all. It can't even with brandnew batteries !
Robert Calk
June 8, 2015 at 12:50 pm
I don't know what an Elco is. You are not supposed to apply power to the insulation tester. It isn't for checking power supplies, it's for checking capacitors and wiring. I haven't had any problems with mine.
Albert
June 10, 2015 at 11:31 pm
Hi Robert, An Electrolytic Capacitor is also often called an Elco in my Country. That's for instance a 47uF 400V type from a Power Supply with Plus and Min Pole. And those Capacitors apparently can't be tested in our AR907Plus device. Mine goes from 100 to 2500 Volt but the HV Output voltage collapses completely when I connect such a capacitor with the Red and Black Output wires. I thought the AR907A was capable of testing these polarized HV capacitors too, but it is just useless for the obvious tasks.
But with no load, or only with a few 2200pF or so, I can measure the Set Voltage without any problem in seconds. But when I attach any bigger Capacitor my Tester goes into Erratic Mode. Or it never reaches the set Voltage. That's why I was disappointed when I tested my AR907+. Any good Capacitor tester should have a much stronger HV generator to be able to test all kind of Capacitors. I think I saw one published in Everyday Practical Electronics not so long ago to make yourself.
I am thinking of building it, because it would be very usefull!
Albert.
Robert Calk
June 11, 2015 at 10:27 am
Hi Albert,
Ok, that is what an Elco is. If an elco passes the flick, capacitance, and ESR tests and you still suspect it, and you can't or don't want to test the voltage across the cap while energized, then I would just replace it and see if that fixes the problem.
I got the digital insulation tester for non-polarized caps and wiring. To test elco's, an analog insulation tester would probably be better. But it would be cheaper just to replace the cap and see if that fixes the problem.
You may also have a bad unit and need to send it back for a new one, or a refund. Also you have to watch out for fakes! There are all kinds of fake components and meters and everything on Ebay - I've complained about it to them with no answer from them! I bought 2 fake Sunwa analog meters - they were clearly fakes. I sent photos of them to Mr. Yong to take a look. I got my money back on them but you still have to be careful. If your meter isn't working right then hurry and get your money back.
Albert
June 11, 2015 at 11:56 pm
Thanks for your reply Robert. So I guess you never tested any polarized capacitors like I have done?
I am thinking why you never should also use the AR907 for these types. I mean... what made you decide not to use your tester with them? It is not written in the instruction manual that we are not supposed to?
I don't think my, or your, AR907 is Fake because it works fine with smaller non-polarized capacitors like you already showed in part 1 or 2 of playing-with-ics.
Or ! Both of them are Fake if they also should be able to test the polarized ones?
If you catch my drift? But if your AR907 also behaves erratic when testing a 47uF 400V polarized capacitor or higher, I can be certain that our AR907+ Testers are comparable identical in functioning. And to answer your question: I tested my AR907 with perfectly new working 47uF 400V capacitors from Ebay China. And the 47uF 400V cap worked splendid after placing it in my repaired supply from my "Switching power adapter without any switching controller chip!!" article.
But the AR907 as mentioned could not be used to confirm if the 47uF was okay.
Albert.
Robert Calk
June 12, 2015 at 10:41 am
Hi Albert,
Yes I have used it on e-caps, but I don't trust the readings. I didn't buy it for testing e-caps anyway.
Albert
June 12, 2015 at 2:09 pm
Hi Robert, if you didn't thrust the readings when using Polarized Elektrolytes it just must be because the HV generator collapses at those high charging currents needed to fill these bigger Capacitors. So I take it our AR907 devices are in fact the same and no fakes.
I have checked my Tester inside and found 8 HV diodes marked D24 to D31. Being D24 a special HV R3000 type, D25 a special R2000 type and D26-D31 ordinary 1N4007 (1000 Volt) diodes.
I also made photos of all components to be able to repair the device if anything would go up in smoke in future.
By-the-way: The R3000 measured about 1375 ohm when it conducted current on the Diode Test on my Digital tester.
And the R2000 when conducting about 840 Ohm. (I had soldered them out to be sure they functioned okay).
Greetings,
Albert.
Anthony
June 3, 2015 at 3:56 am
Hi Robert,
Congratulations on solving the problem ! Terrific photos and a great narrative that makes us almost feel like
we're there enjoying the fun you're having learning and solving electronic hurdles. I love your scope by the
way and it's great to see it's running nicely after the repair you carried out on it a little while ago. I really
enjoyed the article, Thanks for sharing !
Best Regards
Robert Calk
June 3, 2015 at 3:55 pm
Thanks Anthony, I'm glad you enjoyed the article. My scope has been working great.
M Yachad
June 3, 2015 at 11:49 am
Very nice about the Mylar capacitors.
But the Band end should be marked with a BLACK marker, because that is the lead which will be inserted into the Ground rail.
Using the correct colors is much more user-friendly, and prevents mistakes!
Robert Calk
June 3, 2015 at 3:59 pm
Thanks M. Yachad. Well since I marked the caps I know why it is there, so it doesn't matter what color it is really. The marked side goes toward the lower impedance of the circuit, not necessarily ground.
Humberto
June 3, 2015 at 11:42 pm
Hi Robert, great article, good explanations and wonderful photos. I really enjoy reading them.
Have a good day.
Robert Calk
June 4, 2015 at 8:46 am
Thanks Humberto. I'm glad you liked it. It was fun doing this project.
Yogesh Panchal
June 4, 2015 at 12:36 am
At last you got the result; Good effort.
Robert Calk
June 4, 2015 at 8:50 am
Thanks Yogesh. Yes, a good result! I'm glad our friend Steven spotted the mistake I was making - I had a feeling that I was doing something wrong since some commenters said that the IC's should not be very susceptible to ESD.
Mohammed Kasim
June 4, 2015 at 1:18 am
Thank for the good informative article..........Keep on experimenting
Robert Calk
June 4, 2015 at 8:52 am
You are very welcome, Mohammed. I will keep having fun!
STEVEN NEO
June 4, 2015 at 5:51 pm
you are welcome ROBERT, you provide a very good and detail article, nice to read it.
Yes, we must thanks JESTINE YONG to make us together to share our finding.
thanks.
Robert Calk
June 5, 2015 at 12:18 am
Thanks Steven. You are correct my friend.
Tyrone
June 4, 2015 at 6:26 pm
Very good article Robert and thank you very much for the info on the caps which
is new to me.
Robert Calk
June 5, 2015 at 12:23 am
You are welcome Tyrone. Many people that repair amplifiers for a living don't even know about the caps. And of course, the more sensitive the circuit is to RFI, the more having the caps installed the correct way matters.
Capt36
June 4, 2015 at 7:51 pm
Way to go in the persistence category! And, I applaud your admitting, and correcting, your mistakes. I think we all learned a good lesson today!
BTW: I ran into a noise problem many years ago, while building a radio station, using used equipment. The main audio console was a home-brew of a local TV engineer. Most of the channels were quite. But, several had an undefinable noise, which was barely above the lega limits..... I finally traced it down to his use of tantalum input capacitors on the 20 meg-ohm IC inputs. Even though there was no 'voltage' blocking expected, whenever the polarity was wrong on the capacitor, that channel had unacceptable noise. These tantalum caps were the "orange drop" type. Their polarity was 'hidden', by the closeness of the components on the circuit boards. I could see the same problem happening in some of the crowded circuits boards of today's products.... If you Google "tantalum capacitors", and click on "Images", you can see the various physical examples of tantalum caps. There are quite a few there, that I had never seen......!!!
I very much enjoy your articles, and style of presentation! Keep it up!
Robert Calk
June 5, 2015 at 12:35 am
Thanks Capt36. I try my best to be a very honest person to gain Gods' approval. There have been times I could have lied and claimed to make a repair when I didn't. Mr. Yong knows about some of them.
I have seen the tantalum cap page before. I'll have to try some tantalum caps with this method and see if they work.
mahmoud_tajpour
June 5, 2015 at 3:27 am
hi dear Robert I,m very sorry because you finished this article you are mercifuland great scholar you are a model for us I wish you health,love I wish to see you nearly but it was difficult because I did not get a visa to America. thanks a lot.
Robert Calk
June 6, 2015 at 4:53 am
Thanks Mahmoud. I'm glad you liked the article. I'm kind of sad also, but there will be other projects and stuff to do in the future.
Graeme Partridge
June 5, 2015 at 4:14 am
This is what it is all about, experimenting, collaborating and learning, great article, great ending.
Robert Calk
June 6, 2015 at 4:54 am
That's true, Graeme. Thanks for commenting.
Mark
June 5, 2015 at 7:45 am
Hey Robert,
Thanks for the informative series. Experimentation is so important for progress. I also appreciate pointing out the mistakes. Some think it is a weakness to admit your mistakes, but in actual fact is it strength to show the mistakes we make. We can all learn not only from the successes we have as electronic enthusiasts, but also the failures and mistakes. It helps the next person not to repeat the faults.
Thanks also for the information and testing on ICs. I am keen to learn about this area as it is still a little unclear about their testing procedures.
This is a great site that Jestine has provided for us to interact all over the world.
Keep up the good work.
Robert Calk
June 6, 2015 at 5:00 am
Thanks Mark. I agree with you. I'm glad you liked the articles. It is fun to play with IC's and see the different waveforms. I expected to see the IC output a square wave, but I don't know a lot about why certain waveforms are used at different times. I need to do some study on why certain waveforms are used in different IC's.
Javier
June 17, 2015 at 1:04 am
Hi Robert! I was wondering if you could hepl me with some parts of my TV that i guess i'm needing to replace.
It's a 58"TV Philip with box and 3 rearview colours, 1998, that suddenly the image started getting norrower more and more, like if it were an hourglass, up till one point it remained that way "forever".
Ill give you the Model and Series numbs., so that if may be of your help to suggest me which parts i may need to replace.
The thing its im from Argentina and here its very difficult to find someone who really can repair it as Philips parts do not manage to check -in, so i'll have to try to find it outside.
Model Numb: 54R915 7702
Series Numnb: 80580718
Thanks very mucho for your time!!
Greetings,
Javier
Robert Calk
June 22, 2015 at 2:00 pm
Is the OSD affected? Do you have an isolation transformer? Have you checked voltages?
I don't remember hearing about that kind of problem before. I would suspect the LVDS cables, t-con and/or main board, or the panel.
Frank Seldevig
June 21, 2015 at 5:27 pm
Great that you followed it through to the end for us.
Thanks for the "non-polarized" tips, we always learn something new.
Keep it comming 🙂
Robert Calk
June 22, 2015 at 4:20 am
You are welcome, Frank. I'm glad you liked the article. It was my pleasure to share the experience with you guys. There are many people much more knowledgeable than I am, and have some great videos on YouTube.
Yes, it's very exciting to learn new things.
shahid ahmad
May 8, 2016 at 3:42 am
i like your article very much very informative.
Robert Calk
May 9, 2016 at 5:39 am
Thanks Shahid. I'm glad you liked it.