Use Basic Electronics Knowledge To Repair Industrial Electronics - Pure Methodical Fault Finding Pt2
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- Опубликовано: 10 фев 2023
- Part Two This is where our basic knowledge of electronics eventually takes us. Pick up a faulty PCB that you know almost nothing about, apart from maybe it's basic function and use a mixture of intuition, a general understanding of electronic components and circuits, a touch of voodoo and a bit of luck and you have a very good chance of diagnosing and fixing the problem. This is where the money is guys, learn to do this sort of repair and you will find that working on this sort of equipment can be very profitable and also very fulfilling. Here is the conclusion to this two part repair. Watch, learn and enjoy.
Part One is Here
• Use Basic Electronics ...
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SOLDERING
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Thank you
Richard
As someone who has done this type of work full-time for several years now... Your channel really is a gold mine. They're really just weren't many people troubleshooting industrial electronics and documenting get regularly like you do on your channel. Don't get me wrong... We can all learn from folks like mr. Carlson, big Clive, Marco reps, diodegonewild.... And many others. But just one or two of your fault finding videos covers more information than most of those guys in tire channels combined. I obviously learn tons from watching troubleshooting involving radios, receivers, and random stuff Clyde picks up at the dollar store.... But since I only deal with industrial boards and metrology stuff.....i get INFINITELY MORE thought-provoking info pertaining to what I work on everyday... Then some of the aforementioned channels combined. You're really filling a niche and doing it so well and so regularly... And also building a community of like-minded folks that just weren't congregated and engaged on RUclips prior to your channel
Thank you, I guess out of all the ones I made so far, this video (both parts) pretty much represents me at my best doing what I do best, it shows what I can do and where my limitations are. Even if I didn't fix it. Though some guys further down the comments have some good ideas about the possibility of doing just that 😉 So maybe there is a part three also 😉
You said it all, this channel is a gold mind. It’s very hard to find people like as you said, also hard to find people that honestly will be willing to help others to excel their skills in troubleshooting. This channel is definitely helpful to developing the thought. I’m very thankful to have this channel
I'm working with electronics for more then 40 years now, i have made many thousands repairs...but when i'm looking at the skills of you Richard i feel realy stupid . Respect !
A outstanding display of component level repair skills par excellence. Bravo and thank you for sharing a lifetime of knowledge.
I'd love to hear your history someday on "The Amp Hour" podcast with Dave Jones or Chris Gammel 👍
Hey, if one of them would invite me I would love to do it 🙂
I probably would have gone and desolder every part that is near a short circuit but your current injection and IR camera trick is really awesome ! It saves much time. Never thought this way about it ! Thank you very much !😄
Never skip your videos, no matter how long they are, always very interesting, helpful, educational.. Thank you!
Look forward to all of your sessions. I am a retired senior citizen and love to learn from you now, as I could not in the past years. Best regards.
This was another super good video, and entertaining as well. Bummer that this one got “baked”.
Excellent decision to keep running down the rabbit hole, finding out it’s not repairable, before spending any money on parts, and fail, trying to repair it!
Karma for the future.
3:46 police is never going to be able to tell I'm driving with flip flops on my pocket. muahahaaa I'm evil !
Heya, learned a lot from your video's/vlog's but I know I have still a lot to learn some video's have to watch 2 or 3 time before I understand but it's never getting boring or something like that. If it was for me it good get even more in dept/ specialized. I'm even intrested in a deep explanaction about your oscillocoop ( I mean what all the buttens are for) never had that. thank you so much
Thank you for your knowledge and experience giving to this world.
I really love to see to the end and I am going to watch it again.
Thank you for sharing this with us
Very good pair of videos - nice to be able to watch your thought process whilst troubleshooting an unknown board. Unfortunate that it wasn't repairable - do you levy a diagnostic fee in such as case? I assume that you must, otherwise it's a lot of lost time from your day.
Very good work, and excellent advice. Thx!
Thank you for a well done troubleshooting video. Greetings from Monterrey, Mexico!
Your observation about chicos and chicas is correct. That's the way Spanish language is structured. You can have one boy and 100 girls and they would still be called "chicos."
I wish wasa your side watching and learning but this is the second best this. Thanks a bunch I know all the basics but what you are so good at is showing how intuition is working with these things. And you are old enough not to be embarrassed by the eventual failures . thanks again
Great work 👌
Just going to say that I've learned more from this channel than any other. The methodology is priceless and as you say I need to build up my experience. I actually believe that the train of thinking, how circuits are built and the required train of logical thought will come.
Thanks.
Nice job!
very informative video. thank you
Nice job Richard. Another amazing video, I thought the board only had the one fault. Great job tracing all the other faults out. I'm guessing that was a crow bar circuit, with the zenner and what looks like a TVS diode.
And those small looking resistors aren't resistors, they are coils, iirc.
Yeah the zener is supposed to be a crow bar circuit. Tto others, this means shorting out a voltage supply with a cheap component, that acts much faster than a fuse, with the intention of protecting other sensitive and expensive components. The expression comes from the (old) practice of dropping a crowbar across the output of a power source to shut it down. The little cylindrical stripy things are resistors apparently, they are called MELF
@@LearnElectronicsRepair Yeah, I've seen the crow bar zenner in a friends tv box, where they used 12 volts instead of 5 volts. Funny thing was, they had two similar boxs they did the same thing to, but only one had the zenner installed on the pcb and the other didn't. Just removing the shorted zenner was enough to get that one working. Kept the other one myself until I could get a few parts on ali to fix that one too. Still works now 🙂
Great Content...
Awesome video! The thing I learned from this video is don't stop when you find the first problem. Keep looking for related problems. Then try to think what externally faulty condition might have triggered the failure, or once you return the fixed unit it might break again immediately :) thanks!
Great ending ! I know not the perfect ending but top draw educational stuff !....cheers.
Thanks
Thank you so much
oh no, the CPLD went , if one were very obstinate, perhaps you could try extracting its internal flash storage
Muchas graçias ;=)
Also after doing work like this for a little while... You won't have to look for a business. You'll have folks beating down your door with industrial manufacturing in process control type equipment. Along with many other categories. There aren't many folks doing this type of stuff these days... And like I'm sure you are all aware... Companies would rather sell you a new $1,200 board instead of replacing $4 worth of parts. And they're hoping to sell boards like that every few years for each and every machine in the factories. And the crazy part is a lot of them have the old board sent to them before they'll supply in new one. Which obviously get repaired and then just get shipped backed out to other customers.
Hi,
Very interesting video. I was wondering why you didn't almost immediately go for injecting voltage and use thermal camera/rosin/isopropyl alcohol to determine where the short(s) were?
Also wondering what you can charge your client given that the board can't be fixed?
Will you resolder all the parts you took off and then give the board back to your client?
Please keep up the great work. I enjoy looking at videos like this on yours and other channels
1/ You can't inject current into a short until you have found the short in the first place. This PCB has two faults (at least), only after finding and removing the first short could I move on to investigating the second one. The only reason I got that on to the second short was down to 'factor two'... Intuition. And a touch of luck.
2/ This is something you have to organise with your customers before starting. You can have an inspection fee or operate no fix no fee (and make up for the 'losses' on the ones you can't fix by charging more for the ones you can). This will come down to what is good for your business and your average success rate.
3/ Yes I would just refit all the proven good parts that I removed and give the board back with the bad parts in a separate anti-static bag. It wouldn't take me very long to do that. The zener diode that went AWOL, if i can't find it, I will just stick a good 6V 1.3W zener in there. That's my best (educated) guess and they cost next to nothing.
My wife is good at fault finding.
Great video. 👍🏻 out of interest What would cause intermittent continuity between live and ground on a PCB I get beebing instead of constant tone?
Thanks
Hello thanks for video.....then What is repair use compound electronics knowledge?
God Bless.
I have watched a lot of your output and this is definitely in your top five. Nothing wrong with the others, but its one of those where everything just comes together. Who would of thought that you could make the 'simple' process of driving a motor on a door/turnstile so complex. It the hobby world, you would just take a atmega 328p (Arduino chip), connect up to an 'off the shelf' H bridge motor driver and add some inputs, From there you would expand the 'design' with some levels of protection (opto isolation, de-coupling capacitors ...) and have a working system. Would it still be working in 20 year time? If built properly (may be on a board from the guys at PCB Way), why shouldn't it?
I've been to this nature theme park a couple of times. It's called Palmitos Park (Gran Canaria) and it's really nice actually. It is up in the mountains so locals drive up there (and we get big discounts on admission as well if we pre-book online and present our' Residencia' (ID Card). Tourists are generally taken there on organised coach trips, though there is also a regular public bus service from the main tourist areas. You can also get season passes. They have two kiosks at the entrance, one queue for pay on arrival at the manned kiosk and the other for prepaid. They have a barcode laser scanner where you use your entrance pass and I guess it checks if your ticket is valid for that date, and no doubt does so data recording so they know who in on the site at any given time, etc.. So the system is probably a bit more complicated than just operating the motor. I'm assuming only one turnstile is operating at the moment. It's not a huge place but they get hundreds of visitors per day. They also have a sister theme park called Aqualand and you can get combined tickets for the two.
@@LearnElectronicsRepair So there is a bit more to it then. Maybe use an ESP32 instead with a WiFi connection to an office server hosting a web RESTfull service. Obviously not available 20 years ago. The availability of SOC devices these days puts a lot of processing power with input/outputs galore for very little money. I am currently developing developing an motor cycle alarm tracking system with ESP32 + AG9 so it has GPS, GSM/GPRS, Bluetooth, and WifI. Coupled it up also to a BMI160 accelerometer to detect 'initial movement' before triggering the GPS Setting/unsettling can be done either by bluetooth / 8 digit pin via rotary encoder or RFID tag swiping. £30 worth of components that does what a £380 + £20 / month commercial system does (although not thatcher approved). I dare say that guys in the future will come across this sort of thing more often and if you can't get your hands on software encoded in the SOC, then it will be the same story if the SOC fails. However the thriving Open Source community puts it out there for others to use and build on. A bit of a ramble, but as Bod Dylan sang, "The times are a changing!".
Hi Richard. Close to broken ALTERA you have the AT29C257 flash (PEROM) memory. The question is if this flash is using for storing some parameters or is acting like source of program for the ALTERA. If AT29C257 is not broken and you have a proper programmer, you can try to read it if there is something.
Thank you - some of you guys are far more advanced than me in certain areas and that is what makes this channel a real community. I can do 'my stuff' but there is a lot more to this sort of work. That eprom chip is not getting hot so most likely it is good. I can get the Altera IC so if it is worth a try I will replace it
Agree 100% on the "voodoo" part. The 'voodoo' part I tihnk is just innate pattern recognition, that becomes so ingrained into your mind and soul that it becomes second nature. You don't "think" about how you're going to drive home, you just do.
CPLDs and FPGA's are 'dumb' in general. They don't have masked ROMs on them. That's why you had an auxiliary Atmega chip with 8 lines going into it (to feed the configuration data on boot). The FPGA (the one that was getting hot, the one with the white dot) might have been performing just fine. They're notorious for drawing a couple amps, while properly operating.
*Why* they chose to use a fuggin FPGA for a gate system is beyond me-- its not like you need heavy number crunching for a parking system. The only thought I have is for the opto-disc counter.
Finally, once you cleared the main fault, and got the red LED lighting up (giving you some sort of status indication), I suggest you should have tried plugging in a wire to test what serial information was coming in or out. (RS422 or whatever that was). At the top of the board there was a jumper that said "OEM Boot" or something-- which suggests to me that there's certainly a way to boot into a diagnostic mode-- it would have to, since I'd imagine this is just one small part of a larger access-deployment scheme (fail safes for all firedoors, tracking habits of visitors and employees, sometimes even timers for cash-drop boxes even)
Anyways, great stuff
Richard can you please mention the temperature and flow rate for the hot air stations in future videos as I just cannot seem to manage to desolder large components without sometimes popcorning the board even after preheating the surrounding area to prevent thermal shock. I am wondering if it may be my cheap hot air station. Thanks for great content, I remember when you first started and we’re on less than 1k subscribers, I knew this channel would become popular with the tech community.
Sorry, sometimes i do mention it. If I don't state otherwise you can be certain it is set to 450C and full air flow. It's a Quick 862DW. If i am doing BGA work which requires longer heating, it will be set to 350C full air flow and I will be using a preheater also. Nice to see you are still along for the ride, the channel will be two years old on March 24th
@@LearnElectronicsRepairhi Richard it was not meant as a criticism I have learnt loads of shortcuts from you, I look forward to your videos - two years old how time has flown 👍
@@prads4168 No worries, anyway I'm certainly not above criticism that is for sure 😉
Hi Richard. I wonder if you could use the mili ohmeter to trace the short, meaning the component with the lowest resistance reading is the one that has the short.
Yes, technically you could but practically you couldn't. The method of injecting current is much better as that voltage rail will go to many places on the PCB and with the short present you probably can't even work out which pins are actually connected to shorted voltage rail and which ones are connected to ground anyway. 😉
@LearnElectronicsRepair Ya that's right. Thanks a lot
Do you mod the esr meter probe Rich? My mesr100 also have unstable value when shorted between red and black probe
No it's a standard one (bought in 2014)
0:52 - Well thats supposed to be choke coil? Thats why it has low resistance.
30:25 - Contacts of chip are exposed, meaning that we can use oscilloscope to see is chip alive or not.
34:22 - I think its pointless and dangerous to start the board without chip. I believe there are scenarios that can cause more damage to the board. Anyway board is not designed to work without IC, so first is to replace IC.
Good analyses (again). The diode looked to be ESD perhaps as there appeared to be no series resistor. You know about IPA flooding to 'locate' the hot part, northridge also uses flux atomising but that's a bit of a faff. Most 'men' would buy their wife a phone, I wonder what's she's checking the temperature of, ho, ho.
Haha my wife has a phone but she often deals with a lot of my calls if they are related to the local bars and customers we deal with who have satellite subscriptions (our other business). The zener is actually a crowbar circuit, it is meant to go short if the voltage on the 5V rail goes above, say, 5.6V or 6V, thus killing the over voltage condition. This will act faster than a fuse and is supposed to save the voltage sensitive components. Unfortunately sometimes this doesn't work fast enough.
Thanks Richard. What is the app and device that is measuring temperature on the pcb please?
It's an Infiray T2S+ Thermal camera with 8mm macro lens, and the android app comes with it. There is also software for windows 64 bit and linux (you can email me for the links) I made two review videos of the T2S+ a few months ago. It is an extremely useful diagnostic tool.
ruclips.net/video/2X0RAfqPvIw/видео.html
ruclips.net/video/ctmJ97NtMCY/видео.html
I'm so sorry for the late reply Richard. I had trouble finding my comment history in RUclips.
I use an iPhone X but I will take the time to watch the video link you sent. I think there may be a similar device for apple phones?
I really appreciate your time doing these videos. Thanks to your channel I'm getting faster at diagnosing and repairing all kinds of electronic equipment. 🙏
It is an FPGA, but FPGAs are programmed on startup from some non-volatile memory, so it might be possible to save it, if you can find a NVM chip on the board, then you just need to replace the FPGA.
Thank you, as someone else mentioned the same, I still have plenty to learn myself (don't we all?) so if it is worth a try then I can get a replacement Altera chip and give this a go. Many thanks 🙂
@Mr Guru Thanks for clearing this up, as I mentioned it was on the limit of my knowledge but now I know more myself. Cheers.
I an quite sure I identified the rom or eprom in part one (at around 00:07:10) AT29C257 and the processor/microcontroller as MC68HC11
@Mr Guru Yes, apologies (to you both) I got my Altera part numbers muddled (never answer from memory late in the evening).
That said, below the Altera is an Atmel 256K Flash memory, which may or may not be doing the Altera EEPROM duties, or is the main program for the CPU - without knowing the CPU it's difficult to say. If the former, a new Altera chip might fix, if it is the latter, then it won't, clearly.
@Mr Guru The Altera can be reprogrammed, it is (for this type) one of its major selling points. As to being reprogrammed 'by itself', that would be a pointless feature, and no one has suggested it.
I will try to find your other post.
As to "why a guess", at the time of writing my original post you yourself had asked the same details (the processor / microcontroller information), I had merely enquired.
It is difficult, in the comment section of RUclips, to follow progressive updates (the OP comment is reported, but not your comment to the OP, so I don't see it unless I come to the existing comment section on the video page).
Hope that helps.
@Mr Guru Naming yourself Mr Guru does not guarantee anything, I think you would agree.
I am not trying to teach you anything - I've been doing design for about the same amount of time, I merely asked some questions, while dealing with the limitations of the RUclips commenting system to see replies in any kind of useful order from the notification tab. The answers to questions were not shown unless you came back to the video page, hence why I asked and made comments, nothing more, nothing less.
I do, however, appreciate the clarification, it helps. Thanks.
Hi mate. How did you make your probes on your ESR meter? I keep getting an error message whenever I try to zero other probes with mine, other than the ones that came with it.
Agree. The original one is have wiggling value when shorted
Set it to manual range 100R and then it should zero with long leads
@@LearnElectronicsRepair I'll try that thank you mate. Keep up the great videos buddy! Take care.
Did you ever find out what this board goes to? Could it be an elevator door controller? Sorry if this has been answered. Admittedly I have not read every comment.
[What liquid is used to clean the board?]
IPA aka Isopropyl alcohol
Are you from Dublin ?
He from UK
From Stoke-on-Trent, now living and working in Gran Canaria.
Comment for the gods
Where do you stand legally with the owner, can he blame you for destroying his board?
if it wasn't broken to begin with why bring it to a repair shop lol
@@Nebbia_affaraccimiei He could say it was fixable and he destroyed it.
It is not destroyed at all, if the customer wants the board back it can be reassembled no problem.
If it wasn't destroyed already, it wouldn`t be there in the first place
What did I destroy here? But I take it this is a generic question, and it is also a good question. When taking on this sort of work you should sign an agreement with the owner that states prior to starting that state 'while all reasonable care is taken..... etc' before you work on it.
but what would happen if you were wearing a see through shirt
A better question is what happens if you are a girl? I believe this daft traffic regulation only applies to men.
A see through shirt is still a shirt
@@LearnElectronicsRepair What? Girls can drive around shirtless but boys can't. I can see all sorts of issues (none repeatable in this forum) with that.
@@ralphj4012 I think it's a generic law about wearing inappropriate clothing to drive, which includes things like flipflops. Presumably given the on the spot nature of the fine the cops are interpreting it themselves - and, of course, most tourists are not to have the language, time or wherewithal to challenge the ticket. Similarly for things like driving with one arm resting outside the window. The upshot is to save the beach wear for the beach and drive there and back looking like you're taking it seriously. Maybe there's an element of seeing it as another revenue stream from tourists as well. Although most of the headlines in the UK tabloids "warning" about it suggest the fine is €200 not €20 - UK tabloids are dubious sources although but €20 doesn't sound like much of a deterrent nor that they'd have much "fine" left over from the administration of collecting it.
I don't know why you loose so much time. Just inject voltage and use the thermal camera. If you have short this is the most fastest and reliable way and you know it. A quality of the thermal camera is also important. Well even with yours for me was easy visible that the component is the one on the left (Zener diode) from the capacitor you have suspected in the beginning. But when you are not sure and the camera is not with very good quality you can use isopropyl alcohol or rosin evaporator to pinpoint the right component. The second element you have removed was on the input side of the coil so there was no logic to do that after you new already the short is on the output. And yes the shored diode is Zener diode and it was clearly visible on the schematic diagram you have looked at (6:22). And I know that you don't like the low melt solder, because it is more expensive (actually this is not necessary true - I can provide a link to the one I use if you are interested), but it will be way easy to remove all the components from the board, even the IC you have removed, using only soldering iron. Beside that, thanks for the good explanation of how the things work. It is very helpful for me and a lot of other people. Thank you for spreading the knowledge.
The reason I didn't find the correct shorted component (zener diode) was because I mistook the mounting hole to the left of the zener with the top of the electrolytic capacitor to the right of it. I'm not sure how I could have 'just injected voltage' without first finding that there was a short on this voltage rail and then working out what the voltage rail should be and what the faulty component was. Even if I had been able to do it, I when most likely would have missed the short in the motor control IC in part one (which was not on a voltage rail). So personally I don't believe I lost any time, but we all have our own methods of working on this sort of PCB and really there are no right way or wrong way as long as you get there in the end.
Nice one Rich. Let us know what they manufacturer comes back with re that IC.