Industrial Electronic Repairs - Can we do it with general electronics knowledge? 

please don't let negative comments affect you , we love watching you diagnosing , even if it was a simple problem . we watch to learn how to solve on our own any device not to get a solution for a specific product

I did this job for a number of years. In order of steps:- 1> VERY close visual, use a magnifier lamp. 2> Heat kills. Look for burns. Capacitors die in heat... look for shrink wrap on electrolytics. 3> Follow the current, then follow the voltage. The higher these values, the more vulnerable the items are. 4> Inductive loads kill. Suspect power components connected to coils, relays, motors, solenoids. 5> Test each component as a stand alone item, in circuit & out of circuit. Prove it, put a dot on it if good, move to the next part. 6> VI trace a good board if available & compare to the bad one. Ask customer if they have a known good spare to borrow...

You are quite correct - Industrial / Commercial electronics often have fairly basic faults and can be very profitable

What i like the most about Sorin is his spontaneity and honesty, he turns on the camera start recording with no need to edit the videos ! Wish you all the best and i'm sure that your new business will be successful !

We do some repairs for a crane company and nearly every one is a relay problem and the ones that aren't are IGBTs or other transistors. We use JCB irons and we have a great tip for use in desoldering connectors and caps. It is called a cartridge blade and is 15mm wide. It allows you to desolder much easier.

That’s a Graco controller. Probably central lube system. They also do painters and sprayers. The biggest problems with relays in industrial application is the inductive loads of relay or solenoid valve coils destroying the contacts. Relays will click but not necessarily making a contact. Lots of time the repair of the board is temporary because spike protection which most of the times stays with coils on the machine ( usually inside the DIN connectors or integrated in to the coil ) is failed, which in turn will damage the contacts of the new relays rather quickly.

You can always pop the relay cover off, and sand down the relay contacts. Usually they burn out and the stain gives an inconsistent path, hence the sometimes continuity and sometimes not. You can look for automotive relays, you should easily find the volt/amp in a car parts store. You are a master of your craft. Do not mind the internet, keep doing the great job!

I studied Electrical engineering and working on software development. I really love your channel to keep my electrical edge sharp. 💖💖 Thank you!!!!

My guess is, when you open up the relay, the contacts will be defective. That's 99.9% of the relay, and sanding them down is maybe extending their lifetime, but the contact is not reliable anymore. Sadly you are right with one thing, finding this relay is not easy, I did not find it on Mouser or other sources I usually use.

Always learn from this guy love it

Loved the video! I used to repair complex military boards a decade ago then moved into software, but have been getting back into electronics for fun. I was great to see the process you took and what you were thinking through. Reminded me how much I miss it. Thank you!

Simply brilliant and so informative. I have worked with relays on cars but this is much more complicated and you made it easy for us to understand. I know for you this is like bread and butter. Thank you very much.

Felicitări in noua activitate ! Cel mai bun electronist de pe RU-vid! Tocmai din cauza asta îți trimit oamenii placi industriale ,pentru ca ești bun. Am avut și eu o problema cu o placa de la o scara de carat mobila, pai ce am găsit pe cineva sa o repare, nimeni nu se baga vor sa schimb placa de baza 1k de euro....

I'm really enjoy these "Can we repair this with general electronics knowledge?" It could be a great series it's very interesting to watch because it is a challenge to you and gets you excited.

I use a led light to shine behind the pcb to follow traces to components. Works for me.

awesome, i would actually love to see more like this, industrial electronics, fault finding & diagnostic procedures on unknown boards. Have been self learning now for a while, & have been lucky to fix most appliances, as a hands on experimental type of learner, but always feel overwhelmed knowing I still don't get so much that happens within some circuits; find it hard to trace a logical path & understanding how each component is modifying to get the final desired function/signal/output... know what/when to take into account residual effects or interference caused by certain devices or circuits, how to prevent, filter... "so much to learn has I"... Thanks for being a great assistance sharing your time, knowledge & experience.

Hello Sorin. You could mix a bit of low melt solder to the joints, so it gets a lot easyer to reflow or remove with solder wick

That was a very good example of basic troubleshooting. Thanks

Amazing Sorin, keep up the good work! Love from Romania!

Thank you for the valuable lesson and for your efforts to prepare this video, it will be very useful if we “all people that working in this field “ share our difficult problems we faced in fixing boards and we solve it , I personally fixed board with a short in transformer or an open circuit transistor or a capacitor behaves like a resistance

Thank you for teaching us trouble shooting techniques. I find your approach to be very through and very helpful. I see comments saying you can open the relay, and I think most of us know that, but depending on the environment this board has to endure, you might expose the workings of the relay to moisture or dust when it's put back in service. My first guess was in total agreement with the relay being bad, as it IS A WEARABLE part, it additionally has moving parts, which has always been a hot spot for trouble in electronics. My eye kept looking at one of the DARKENED pins on the third relay every time he would flip the board, but maybe that's not an issue. While relays get old and wear out, if it was from poor engineering or intermittent problems with the other equipment it connects to, that's always where my mind is concerned.

If the load is a 12v dc motor you could consider 2 automotive 40A relays. They are cheap.

Great Troubleshooting Techniques! Relay contacts have been using cheaper & cheaper alloys for years. It follows there will be high resistance contact failures building up now. Platinum contacts seem to be Mil-Spec only and "silver alloy" can often mean nearly anything today. I've even seen just bare copper posts! Tough world. But relays are also designed with families of footprints, so you may be able to source a Suitable Substitute based on footprint and specs.

Hello. I am a faithful follower and I really like your channel because I learn. Many times I have found faults in relay contacts and have solved them by cleaning with fine sandpaper. trying not to wear the material too much and sometimes using silver solder in case of extreme wear, checking at the end the correct alignment of each contact. I send cordial greetings, wishing you good health, I greatly appreciate your educational efforts. Thank you very much.

This happens to high capacity relays quite a lot...over time, the internal contacts are exposed to arcing from all that high amp swithching and develop carbon deposits whereby causing poor/intermittent connections. So, one way to fix outside of replacing the relay (due to either parts availability or production wants to reduce downtime) is to, if possible, open the relay housing and clean the contacts with fine sand paper and blow the work clean. The caveat is to make sure the contacts are still is good condition and NOT worn out from all that arcing. Thanks for posting your work, I enjoy all the forensics. Cheers from New Jersey.

Years ago my customer had a number of industrial machines which booted off a specially formatted Conner hard drive. One drive failed, and the customer was quoted a stupendous amount of money for a replacement plus installation - in 2022 money it would be ~$20,000. I found a forensic software (that could clone one of the working drives onto a larger readily available hard drive and got the machine working again for ~$500 in 2022 money. My point is that suppliers of industrial electronics know how to rip a huge hole in their customers' budgets :) In this case I replaced every one of the 7 hard drives around their plant, and saved them a huge cost. The vendor had no idea how it was achieved, and we didn't tell them either.

Very interesting video. I have wondered about the issue of heavily loaded components and testing them with a digital multimeter. I still use my old AVO Mk8 for finding faults but even that doesn't simulate a heavy current. Liked and subbed, thank you.

That company was acquired by hongfa technology and once on their page select Products, there you can choose a suitable replacement (it could be similar and I would risk it). There is also an authorized distributor for Europe based in Germany and for North America it is the same name as the previous company. On the other hand, I remember the relays (12, 24 and 48 Vdc) used in the old CRT TVs. Also those used in the variable DC regulated sources of our technical schools (5, 15 and 30Vdc) that we students damaged so much. All the best.

Greetings I'm new to your channel and started following you regularly. I also deal with electronics and work in industrial electronics. usually such high-power relays burn out due to frequent sparking. My medicine is temporary contact cleaning until the relay is replaced.

It is not enough to clean the relay contacts. We can assume that because of the oxides caused by the spark, the contact is not firm but random. But let's not forget that it is a power relay, it means that the CuZn armatures are affected. This is the major failure in a power relay, not just the "contact punch". The solution: a new one. Good job Mr. Sorin and well explained.

Fault is clear, if you can open it without braek it, you could check the inside. Commonly there are "only" some "burnmarks" because of the load to switch. Best case, you can clean it to make it work again 😉

Mulțumim pentru tot ce ne înveți!Mulțumim!

i had that problem multiple time with motocycle ,the relay work but its the contac who are corroded,,the only thing i did it was to open the relay and using a very small paper sand to clean the contact head inside ,it was working every well all the time

Thanks for the troubleshooting skills video.

Of course you can, I always repair industrial devices along with laptops and phones. The technique is the same that you use for laptops, trouble shutting always starts from the voltage of the power supply and so on. (It must be said, however, that if you do not know the electronic components such as power transistor transformers and voltage regulators that are used in the industrial sector, it is difficult to understand the circuits. Also applies to older CRT TVs).

Switched from consumer to industrial almost 2 years ago now and honestly, more enjoyable and, aside from catastrophic failures, more repairable. While there are some serialized stuff, and proprietary software you can't access and such, overall the circuits are less complex and easier to understand. May also help that they're usually much larger than say a phone or tablet pcb, so you can do repairs even without sight assistance (if you have good eyesight)

Hey Sorin, as always great work! Should not fix the issue only cleaning the contacts in the relay? I heard you saying that it will be dodgy...but indeed, you know relays, getting old (escpecially with capability of 40A) can get a lot of oxidation and burnt spots...some good cleaning with alcohol and sandpaper to get back the old untouched sourface, im my opinion, should be quite a good fix for these kind of boards. Probably on an old type of board and unique tool, you can not use very ofter the solution "oh ok i will desolder and solder a new piece". The Master Sorin, would probably just opent the relay case, clean, sandpaper clear, close it back and boooooom! Good as new, evend for less money for the client. Ofc the thingy will get used and old again, and the relay will need the cleaning back again...but what can you do

Thanks for this good learning vid.

Hello Sorin, enjoying your videos as always and i like the doggie way you fix things sometimes because here in Zimbabwe its difficult to find most components. Thank you. Your tutorials are really helping me. I like you so much

I saw the relay and guessed ones probably faulty. I think industrial components like this are built to a standard design - so should be able to replace with same spec'd relay of different makes.

Problem solving process is the same in every case. 1. Identify the problem 2. Gather information about the problem 3. Think, analyze and test. 4. Implement some remedy to isolate or repair the problem. 5. If problem persists, go back to step 1 and recycle the process. If problem is gone, you are done. When it starts working, you should stop fixing it right away.

Sorin, looks like this relay was manufactured by California-based kgtechnologies, and they have a website and a European office. I don't see the K981P in their catalog, or anything similar. It looks like they make mostly latching relays. Which means this relay might have not only coil and contact terminals, but also two reset terminals, kind of like an SR flip flop. Searching for K981P on the web returns nothing, so maybe you can try emailing their support email. Thanks much for your videos.

very interesting, thank you very much for sharing!

Skillful 4 probe handling!

Lots of 5-10 year old integrated modules for industrial uses out there. If they get damaged, either the replacement module costs 3-6k usd or is unobtanium. In the latter case the customer would need to update all automation to most current components. That’s why repair of these is soo well paid

Sorin first job: loose wire, I'm disappointed ... gets second job: so longggg, 41 minutes of troubleshooting haha! Keep em coming I enjoy these kind of new jobs!

Good stuff as usual Sorin.

Negative comments are for haters, continue the amazing job you are doing.

I really enjoyed this video.

Thank you for the video

Greetings, well done finding the problem. Seems to me the faulty relay may have some carbon build up on the contacts since it is 40 amps going through.

Very good job. I'm new to watching you and love how you explain how the circuits work. Im trying to learn.

The Problem with trying to Revive the Contacts is they are Coated with a Mixture of Conductive Metals to keep the Arcing to a Minimum when they Open & Close, thus greatly Extending their Lifespan. Techs will File them Clean and get them Working for a time, but that Special Coating is now Destroyed and generally will not last long.

Often the designers use two pairs of contacts of the same relay in “pass through loop” fashion, in time critical applications to reduce the chance of contacts welding up and increasing the “turn off” time. Same goes to choice of SPDs for that application - for example simple fly back or free wheeling diode is not feasible in that application because it is increasing the “turn off” time and disrupts the correct machine operation. Also snubber types can induce “ringing” with the same results. Usually in time critical application the TVS or free wheeling diode back to back with zenner is used, to shorten the “turn off” time.

Sa traiasca domnul Sorin , de mult nu a ti mai reparat un amplificator audio sau ceva similar . Astept cu mare interes.

Your a verry good teacher

Salutare! Este o placa de la un utilaj de aplicat spuma poliuretanica! Rolul ei este de a doza materiale bicomponente( A si B) iar partea cu Hose este pentru mentinerea temperaturii cinstante pe toata lungimea furtunului!

i haved always learned everything for you sir,

Thank you so much! !!

Continuity mode on the multimeter can be tricky to check relay contacts. I would be using a load to test the relay pins, like 12v with a car lamp.

Measure the contact resistance when ON, cycling it several times. It should be consistently under 0.2 Ohms or so. The specs will give the expected contact resistance. The beeper is continuity, but the Ohms reading is your guide to the condition of the contacts. Replace the relays. That way you will probably not see it again for 10 years.

Great job narrowing fault to relay contact

I wish you were live streaming this so I don’t look stupid yelling at my phone telling you what pins on the relays are what and what’s wrong with the board! Your doing a great job so far though. I’m only half way through the video right now but I have a feeling you’ll get it figured out.

Had a van control unit recently, customer had read online it was a relay problem so asked me to swap it. I said symptoms sound like solder joint, but sure. Then 'fixed' for months until he brings it back and asks for different relay change. Both times, I also touch up any joints I thought worthwhile including the MCU. Second relay didn't fix it (it was unlikely, as I'd said in the first place). Finally, got him to identify the spot on the board that 'turned the fault off and on when pressed'. Dodgy via, completely not possible to find with visual inspection - but we got there in the end.

Ty I got my first divine because of you

Also good eyeball inspection is a good thing. 90% of failures are visible.

Carlson's Lab has an interesting video showing the use of a scope, octopus and pulser to test relays. Even at low current a relay like this should show lots of noise. Search RU-vid for Carlson relay testing. Maybe too much setup for a single repair. Thanks, good video!

I wish you good luck looking for a replacement relay Sorin. My quick search found the maker no longer stocks this part and doesn't even have a data sheet so you can try and find a substitute. You may have to go down the "dodgy" pathway and open it up and try to resurrect the contacts and or spring mechanism. Your website clearly indicates you service computers and related consumer devices, so why the first 2 jobs to come in were industrial equipment types is a mystery. Maybe the third one will be more familiar territory. I noticed a lady called Diana seems to be using your desk and mat for fixing her iPhone. Do you have to "rock paper scissors" to see who gets the desk?😁😁😁😁 Cheers Eric

To me it is good just to get a start. Next maybe they know your skills and sent it anyway even though it is not a laptop or phone. Keep up the good work

You are always the best.

Are those 220 mosfets actually diodes? I noticed the "D" silkscreen designators on the board. Also, if the relay is switching motors, large inductive load, having large diode to protect the relay contacts from excessive arcing on opening contacts would be expected. I would check relay AND diode. Maybe open diode will cause contact arcing and shorten relay life.

I literally have one of those one my bench right now. Burned up a contact on the hose circuit and one of the contacts on the relay is not working at all. I contacted the manufacturer today to see if I can get the relays, but I will likely have to modify a new relay to work in place.

The relay part numbers should cross over to quite a few replacements. You have to match the coil voltage, and then the contact voltage and current. Other than the footprint, older 12V automotive Headlight relays should work. I have a number of 40 Amp automotive relays for robot projects.

When I worked for an electronics firm that did contact work, in the 1980s, nothing ever worked. Engineers had to tweak the circuits !!!! Back in those days no components were the same !!! You got all different values of capacitors, transistors, resistors, so the top 5% would go into expensive equipment, and the rest would go to make cheap electronics or be scrapped !!!!

Thanks Great Men☺️

I'm getting same jobs as u do. No laptops no tablets. But alot of different equipment and car boards motor houses. So much more money in them rare boards. Some of them cant be replaced. Some of them cost over 1 k or 2k

At 18:30' I stopped the video and I can see the case of relay A has a bit of deformity on the left side. Perhaps, a sign of overheating with regular use? It looks like the casing has slightly melted on the edge and deformed. A sure sign of excessive heat inside. Thanks for an interesting troubleshooting video.

Din experiența mea proprie, releele trebuiesc schimbate, chiar dacă le desfaci și le curăți, tot vor creea probleme... Amintește-ți de platină 1310😅, vă dați seama dacă alimentează motoare ce curenți de comutație suportă aceste contacte mai ales la start. Viața acestor relee sa dus. O zi frumoasă!

This was a very hard fault to find. Nice testing technique. Maybe you should add industrial electronics to your website and profit from it. There's demand for it, that's for sure!

Sorin on the “HOSE” socket there looks like a dark pin and on the plastic it looks like it’s got hot the 2 pins to the left of the relay

A tough job. Intermittent fault on a board, no drawings. Chances high that it's a relay but you can't be sure. If I can't find anything on the bench, I normally go to the factory and fault-find on the machine. That way, all the conditions are set up correctly and the fault is most likely to show. Then you can pinpoint it. I don't know if that's practical for you and it depends on how important that board is. If it's critical, factories will pay anything to get their machine back up and running because they are losing production and that's massive expense. I normally contact the manufacturer of the machine and find out what they have to offer. They might give you drawings. They might supply spare boards. If you can get drawings and you can go to the factory, that is your best bet. Or a replacement board and you can mark that up and make something. The nice thing about industrial is you can bill for everything. As long as their machine works, they are always happy

Could be a dirty relay contact, can it be taken apart and cleaned? Also, if your not supplying enough current from your 12v power supply, it might not be pulling the contact closed tight enough to make a reliable connection each time, “esp if contact is slightly contaminated from previous years of normal arcing caused by heavy load switching.” Also, how do you know that you are not going to damage the relay driver chip by back-feeding the output of the chip with your external 12v used for testing of the relay clamping when the driver chip is still soldered in-place to relay coil? I would try to locate a new relay with same coil voltage and resistance, as well as 40A or slightly greater contact current rating, then point to point wire to the board accordingly, and then silicone rubber the relay down to the board with non-corrosive silicone rubber “non-ammonia based”. If the new relay coil is close, or slightly lower resistance, you could always add a in series resistor of proper value to increase the coil resistance seen by the relay driver chip, “as long the replacement relay is not to much lower in resistance. Otherwise the new relay might not clamp tight enough from the driver IC output. Good luck 😎👍

From a mile a way I can tell that's a stepper driver.. It could be closed loop but the min I saw those mosfet..

The proof that the relay contacts are bad is the inconsistent ohm reading when the contacts are closed. You can sand smooth the contacts to get by sometimes but a new relay is the best repair option.

Great detecting.

More industrial repairs please

It's KGTechnologies or Hongfa. Graco makes membrane pumps. Couldn't find the relay anywhere.

Hi Sorin. What microphone do you use? Thanks!

I like the 2 hand, DMM and PPS lead usage. Not easy! I would just replace all 3 relays. Automotive relay is about 40, 50 euro. Cheaper than new board

kg doesn't produce these relays anymore. You can only do a botch job using another relay, but you would need to make sure how many amps these motors really take. Maybe check the MOSFET specs. A 40A carrying botch job would not be easy. But probably you don't need 40A. You could also ask the customer if he has another broken board.

Industrial and commercial repair and service contracts are the best because you are guaranteed payment on time nearly 99% of the time unlike individual / residential jobs who will stiff you of the bill if they can, you sometimes have to fight people to get paid and most go unpaid because it is not worth the headache. This is why I refuse individual service jobs in the residential markets and only take on bigger contracts.

Hi Sorin If there is no spare part to replace the relay. Is it possible to open it and fine sanding between the contact points?

Industrial electronics can be a pain. Yes, most faults are simple and obvious. However, when you can't find those big faults where do you go? The boards are usually quite simple. Maybe a handful of smd components and chips and everything tests good on a meter.

Sir i am thinking can we use 2 12 v relay if not found excited relay

Industrial things are usually easier to work on, you get schematics, repair manuals and it's made easy to disassemble unlike most consumer stuff. There's no nonsense, they can't pull the Apple-type nonsense with industrial products. I have a friend who fixes avionics for a living, he won't touch an Ipad.

What is that yellow tape (name)that you used on some SM IC CHIPS ?

I have worked on industrial electronics and quite often the customer will send in a board like this with no fault details, you have no idea what it is from or what it does and yet you got to repair it. If this was a board I received I would have removed the relays and checked them as not always safe to do in the circuit because of back emf. checked all the semiconductors perhaps do a cap change. nMost of the time items like this are returned untested as you haven't the technical information.

Please explain how you could safely inject many amps like that on the circuit (on the relay) safely? The current won't stay in only in the relay, right? It will affect the whole board right? (Sorry for the basic question, I'm a beginner)

6:07 bottom left corner of the M .1 uf cap, is there a chunk missing??

Wow that *is* a serious heatsink :D