A New Way To Trace Short Circuits in VRM Using Basic Equipment : Find Shorts Motherboard and GPU
Here is a different way to trace short circuits, particularly in VRMs found on motherboards and graphics cards, using just a bench PSU and a millivolt Meter. I've not seen this method demonstrated before, maybe it is a new way for you to trace these faults?
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I work in collaboration with:
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Gran Canaria Uncovered
/ @grancanariauncovered (with Detlef and Julie. Not electronics related)
Det Builds Stuff - / @detbuildsstuff8128 (Detlef)
Retro Upgrade - / @retroupgrade (Carlos)
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Thank you
Richard
Love your channel! For those of us left who are trying to fix the world's Electronics, your wealth of information is GREATLY appreciated! So, a huge thanks from Kansas in the US of A!
Fellow Kansan here. Are we the only two Kansans that want to repair electronics? Can't be very many.
@@benjiwiebe8128 We just might be! lol.
Another great video thanks Rich. I’m definitely learning something from every video you put out. Keep up the great work and I hope you are well.
Love these videos. Thank you for taking the time. I spend hours watching soaking in the information. From being a complete novice to now, at least, being able to identify components and their functions. Also wanted to add that you have seriously got the best eyebrows in the business ;)
Well done! I always learn something. I am going to get the milliohm meter you showed earlier as well. Thank you.
Thank you for everything you do, those explanations and instructions are big help for me! Much love from Poland
SMART POLAK.
Thanks for the knowledge and your time
Thank you! Tremendous value there... so easy and I would never have thought of that!! :D
Master, you are a great teacher. 👍 thanks
I've used this method for the last 30 years since I saw a special instrument for locating short circuits. The instrument consisted of a current limited power supply, a VCO (Voltage controlled oscillator) with a couple of different ranges and a speaker. With the VCO and speaker you didn't have to take the eyes off the test object, the frequency of the tone told you if the volyage increased or decreased. It was sensitive enough that you could easily follow the current even on a power plane and shorts were located in less of a minute by an experienced operator. The instrument was used on a manufacturing line to locate shorts, mostly solder bridges, on boards that failed the function test after being wave soldered. But a bench power supply and using the mV range on a multimeter is good enough for casual use. I've mentioned the method in comments a couple of times on youtube over the last couple of year, but I don't know if I have commented on any of your videos before. Most repair videos only looks for the hot spot but that only works if the fault is a" high" resistance component that failed and not a solder bridge. If the fault have a resistance that is close to a circuit board conductor (for example a solder bridge) the heating is spread out over the whole current path.
This is very true. If you have a 'dead short', especially on a PCB with good heat sinking capabilities, then nothing is going to get hot if you inject current. I've shown many different ways to locate shorts, especially in multiphase VRM and this one stands up well against the others. Particularly because it only needs a variable PSU and a multimeter. Heck you could even use a fixed voltage PSU and as long as the short does not suddenly go open due to the current you would get away with it
Maybe you could combine the fixed PSU with a cheap buck converter to dial in what you need@@LearnElectronicsRepair
I built something like that too, it was a game changer after fixing tvs for 20 years without one lol. I found it particularrly useful on data lines that didnt get hot or anything , the thing would just not start up because it detected a fault , this was a completly none destructive test that was fast and effeicient. Unfortunately shortly after I built it everything got so small with sm tech and my old eyes and shaky hands could no longer cope so I retired and never really got much use out of it, I still have it somewhere but probably not working lol.
@@FlyingFun.Bisa kasih tahu cara membuat nya?
Boleh tahu cara membuat nya, atau rangkaian
Thanks for the advice and info
Wow 500 views 50 minutes and no comments! Did I stun everybody? LOL
I'm a slow typer/tapper(on mobile) 😁😁
We're speechless. 😉
Did you find the treasure?? Is a ❌️ on the Map?. Have you seen pirates ?? ... Ohhhh,, sorry wrong video🤣🤣 All good Richard, super repair video .. are your meassuring probes eventuelly a little bit to long ?🤔 Your infrared cam is amazing .
I got the p2 after all the videos, it’s very good, I haven’t seen a voltage drop check to figure out the side of the short before. That’s quite ingenious, another tool in the mental toolbox! Well done Richard, thank you.
This method of measuring VD across a component is used when fault finding 12v car electrics with a parasitic draw. Fix m volt meter across each fuse in turn the circuit with VD across fuse is the one with parasitic fault.
That's a good idea it's the first I've seen of it on electronics. I've normally seen that on breakers and switches to see if there's a high resistance fault.
thank you for sharing and making this informative video
That’s a nice board. Giving voltages on the silkscreen makes repairs easier.
The gold nugget in this video starts here: 16:13 and is the absolute best way to find shorted paths. To have current flow there must be a resistance _and_ a voltage drop!
Nice repair, as always!
Hi Richard... that was excellent and thanks for sharing. As an EX TV Engineer, and I do mean EX having been made redundant in 1998 and realised that trade didn't really have much of a future, I jumped ship and moved into software just as SMD's were becoming a tad too small to see 🤓 I spent my years as a bench engineer focusing on VCR's and early satellite boxes rather TV's. I was always more suited to the low volts, high tech kit rather than the high volts, low tech TV's we had back then. For some inexplicable reason the "Video Department", as we were known, was also responsible for Microwave Ovens! I still have nightmares about Mrs Jones of Haslington who's oven repeatedly but intermittently, blew a fuse! Got there in the end and life would have been so much easier if she had bothered to mention it only ever happened when she used less than full power 🤬 But that was a lifetime ago now and the therapy must work eventually! Anyhow... I'm waffling. Love the new technique, I've not come across it before, at least not that I remember, so well done sir, full marks.👍 You got yourself a new Sub and I'll be binge watching your back catalogue to see what else I've been missing. Thanks again, keep'em comin' Cheers
Thank you for your teaching I’m pretty much self taught and still need a lot more teaching your videos have helped me out a bunch thank you and continue the awesome work🎉
This was like watching you find the last gift under the Christmas tree, and it being the thing you really, really wanted. 😂👍 Great job and thank you for all the teaching that you do, Rich.
Good video. I haven’t a clue what you were talking about. I don’t understand electric but found it interesting. Thanks
Nice video, well done, thanks :)
That is nice that they added voltages, I haven't seen that.
Many thanks Sir
Good explication Thank you .
Very nice video ❤
good work! Now put a heavily modded Amiga 500 board and keyboard into a Commodore PET chassis. Gotta redo the keyboard area of the chassis and swap out the CRT and related guts, but the end result would be WONDERFUL!
That is how we look on the car where the current is going. If the car has a battery drain, when it should be sleep. You then just measure a voltage difference on fuses with mV setting and that way you don't need to take the fuse out and have a chance to wake part of the car up when you try to find the short/broken component...
Thanks a lot Teacher.
Thank you
Good Troubleshooting Logic. A Third method to find the shorted component it to spray a area of the board with atomized powdered FLUX.... Saw this on another video channel where the brown flux powder melted on the hot components. THAT is actually what I was expecting to see in this video. But traditional troubleshooting worked just fine.
Thank you for this video. If you put a very limited current in at the input (top right black external socket) would the infared camera pick up the hot spot you found on the small square black chip?
@phenej The heat generated is proportional to the current. Watts = Volts x Current. The thermal camera can detect and clearly show temperature difference of 0.1 degrees but you need to give it a bit of 'welly' to get the faulty component to show up. As most of the current was flowing into the short then it probably would show up if you injected 12V into the coaxial power connector but you are likely to kill the buck controller generating the 5V rail (from which all other rails are generated on these boxes) in the process if you don't limit the current. This is in particular why I set my bench PSU to 12V 1.25A when I first applied power. And why I then proceeded to find the derived voltage rail that had the short once I knew it was not on 12V.
Great technique of fault finding. I am reliving my younger days. I almost always agree with your approach while i have a hard time with your accent i replay portions to catch all words. I think it has to do with my hearing those audio amps in the 70 sand 80 s must have affected my hearing 😅
I watching SORIN ELECTRONICS. he is master of the supplying current to the circuits. No soldering quick method simpler and reliable
Thanks
Smart 👍
thank you
Well done Is there a Part 2 yet please?
So glad I've just found this channel, I've been considering getting into the electronics repair field as I have a general knowledge of electronics and due to back injuries can no longer do the automotive technician/ collision repair work I've done the last 25 years. I've always had a passion for repairing things since I was a kid, not to mention my granddad was an old tube style TV repair man for awhile in the 80's after he retired from International Harvester. With that said aside from the obvious of a good solder station, multimeter, microscope and desk power supply what other tools would you recommend I need to get started in the repair business? And btw hello from Southern IN, USA!
Voltage drop to the rescue again 🤣😂 Gj Richard
Yeah it did Carlos. I guess you liked it, Det was rather impressed when I showed him this during filming 🙂
Nice work figuring out the short. Could you tell us what macro thermal camera you're using? I didn't see it in the affiliated links. Thx
I need to update all the links this month, they are a year old now. The thermal camera is an Infiray P2 Pro. If you want to give me some commission from AliExpress, find the ? in the URL for the item and change it to ?af=ler2022 then order. The price will stay the same. Thanks
Faster to make a frost in the PCB then power it at 1a. The frost will burn off on the current path to the short...
Very good Sir
Thank you for everything you do,
Great video, may I ask what thermal camera and macro lens you use please. Thank you.
Another excellent explanation. Thanks for sharing your knowledge, Richard. BTW: could you explain how to insert those pins inside your probes?. They are great for SMD testing!. Even a short video with the method will be great! TIA!.
You buy them that way.
@@stargazer7644I have the Pomona ones (which, by the way are excellent for SMD), but these ones seems to be less expensive. And in my humble opinion, they look like nails inserted into the plastic. Even they are extremely long. Please, if you have a link with this probes, paste it here. I never saw them. Thank you.
@@fichambawelby2632 I tried to give a link but YT deletes the whole thing
@@englishrupe01thanks a lot!
@@englishrupe01maybe you can write to
The white strips generally on cheap supplies mark the POSITIVE wire! And positive isn't always the middle it's different on units!
NICE
Hi, I wish I had a mentor like you. Greetings from San Diego 👋
Nice bro.
Personally I prefer to use an LCR-Meter to find the right side of the coil, as you demonstrated sometime last year. That would also be a nice and cheap little tool; it shouldn't need more than 2 € to build a short finder operating at some 5-100 kHz/.5V . That should make it safe to work on CPU or GPU buck converters, even for intermittent shorts. What do you think?
There are lots of different ways to do this. Some work better than others in different situations. I hadn't thought of this method before and it definitely has it's place. Certainly with multiphase VRAM and a short on the Mosfet side this is going to help you a lot, especially if you only have very basic test equipment (variable PSU and multimeter with millivolt range)
Which thermal camera do you use please? It gives a very accurate image I must say! Thanks for the uploads. Take care.
Infiray P2 Pro I reviewed it here kzhead.info/sun/napuk8qqfWpoh6s/bejne.html
Where can I buy the thermal camera in this video sir ?
Thank you 👍🇮🇪🙏
I have used a q tip with alcohol to find if it gets hot it evaporates really quick also. Not a by the book technique but works on the fly.
Anything that works for you, if even only sometimes, is a good technique. This is just another one that occurred to me and it only needs the most basic equipment so maybe give it a go sometime. I will certainly use this method again 😉
nice idea
I love to use the thermal camera now, because it can see more than one hot spot, and I see people try to fix one spot but missed the other real spot.
@@jxmai7687 If you want to save some money and see all hot spots, you may as well use ice spray.
Heya, good you have the thermal camera on this 1 hope you make a part 2 wen you received the chip
🍻 cheers
if this is for real then I really really think this is what I need
Great
As always, an excellent and instructive video. :) What thermal camera are you using there? I'm asking for a friend. :P
Infiray P2 Pro I reviewed it here kzhead.info/sun/napuk8qqfWpoh6s/bejne.html
thx@@LearnElectronicsRepair
What exactly is new about this process? I use all these methods and have from day one. The comparison with a known good unit is a luxury we don't always have. The next step is components with a known high failure rate. The 1206 SMT caps are high up in the list of suspects. Injecting current is also a well known way to track faults. Another problem is emerging from recent design techniques. Battery power means low current operation. Intermittent surges is one way to save power if the object of the circuitry can stand it. {PIR detectors is one example}. Sometimes right down into the uAmps. This means that any track leaks as provided by condensation in cold overnight conditions together with atmospheric borne dust can create leakages. I brush the PCB's with Meths or Isopropyl Alcohol to remove these invisible destroyers. They sometimes need more than one try too. With modern construction methods its so difficult to lift feeds in order to isolate sections. We need some magic methods more than ever we did. How about the IR detector? The digital camera sees IR and can spot hot-spots better than we can.
Nice
Definitely going to try this to hopefully recover a Lenovo M720q motherboard that just refused to do anything at some point.
shortcut to most interesting bit: 16:19 "i was just thinking about this, as i do..." measuring voltage drop across the coil....
In my day we would replace the fuse with a nail and 'tune for maximum smoke!' You could soon see which component was bad,
what happened to your milliohm meter you made?
Try your milliohm meter and blow warm air on the components say through a straw, it should change the meter reading when you find the bad component.
I wish you would link your power supply in the crotch box. I have been having a really hard time finding something with a do all low voltage DC range and don't have enough room for 4 or 5 units.
crotch box?
@@LearnElectronicsRepair Common American nickname for the "Description" area of the video.
I used a PC speaker and two AA batteries for testing on a Toshiba 40 gb laptop drive, found the problem, but couldn’t fix the bad sectors.
Thanks for sharing. Which AliExpress shops are buying your I.C?
For these sort of chips I find SUHMS shop is quite reliable
@@LearnElectronicsRepair Thanks 👍
Please may I ask if you can post a vid (or two) on replacing smd's as well as the chip in the video? Bad habit of lifting or moving other chips around in process or burning them . I am so nervous to remove the problem parts off of boards.Videos are absolutely great! Thanks for all the good advise and alternative thinking to look at problems in more than one way.
If you have, try to use a heating bed of some sort that heats up the PCB from the underside (and possible powerplanes that soak heat away from your hot airgun otherwise) thoroughly to about 80-90 degrees Celsius or even more and let it soak heat. Try to desolder the chip you want that way. That way you should have less of a problem getting the chip you want to remove to heat up quickly enough without bombarding other parts that might want to try and wander off as a result. My brother has used aluminium foil as heatshields around the part he wants to lift as well, to prevent the problem you have, and he takes high resolution pictures prior to the procedure so he can check for parts that have decided to swim away.
You could find which side of the circuit is shorted using multimeter and power supply, but you probably won't be able to pinpoint certain shorted component. And this is where you use a thermal camera. I would argue that thermal camera is basic equipment. Rather not. And if you had a thermal camera you wouldn't need to spend time to find out which side of the circuit is faulty.
Richard is the real deal Holyfield
Genius .. ohms law just keeps giving !
Motivates me to dig out an Xbox 1 that's had me stumped 😅
When you were initially tracing the short you found one side of the coil had higher resistance to ground than the other. Didn't that reveal which side the short was on right there?
questions how to converts HDM cables without any electronics amplifiers converted to normals videos RCA plugs to se the pictures
Iv always found working from ground quicker than from power
Weren’t these the ones that are both 12v and 5v supplies depending on the model ? Another case of incorrect voltage ?
Yes and probably a 5V PSU killed this one too
@@LearnElectronicsRepair maybe a circuit to protect against this issue could make a good video ?
Cool...
The shorted MAG box likely burned out the wall wart PS. Can you troubleshoot the wall wart PS too?
It wa dead and I thre it away to be honest
Thermal imaging camera is the best tool here🙂
you can do that on a voltage regulator ...but if you dont have the osciloscope or a proper voltage it can burst/ breakdown the componenet...im not so confident with this method of doing electronic short cuircits because I never do it directly (wiring a anode or a cathode of a mosfet/voltage regulator posibbly) Im not keen to this method but ok..thaks for showing this..
Hi my friend. Thanks for your video. Where did you bay the terminal camera.. Can you tell me where l can buy it. Thanks 🙏 and keep going.. l add you as favoriete.🎉
Man, i really want to become an electronic engineer, problem is i finished my masters in finance and i cant just go back to college, i need to get a job, education is free in my country so i was thinking about applying next year, this way i can focus on my soon to have job and in the mean time try to learn about electronics as much as possible, i have a little knowledge in programming with c and python, i truly want to become an engineer and use my finance experience to start a tech company one day. Wish me luck everyone
Best advice --- well I don't have a degree in anything. No university course that I know of will teach you electronics repair. The only qualifications I have apart for m GCSA O-Level and A-level is a City & Guilds in TV, Radio and Electronics Repair (vocational training full time one year) and a HNC (Higher National Certificate) in Microprocessor Systems, Design And Programming (2 years part time) I have three distinctions in each. But the only way to learn to repair electronics is to do it. And learn from your own experience.
@@LearnElectronicsRepair yeah that I was thinking, I'm planning on buying equipment and build small circuits for small projects and learn through these projects, thank you for the advice.
Subed :)
Was voltage injection at the coil really needed to find the fault with the thermal cam? Why not use the standard powerplug, it was taking >1A, the chip would glow on the thermal too like this me thinking?
Why are there coils in a DC circuit in the first place?
link to that Thermal cam??
Elecrotonics oldtimer here; the only way to finally lay the problem to rest, would be to change the little chip. Why is because the chip could be getting hot because the CPU is drawing excess current.
It'd be nice if I could bring you my cassette deck with a 12 pack of Guinness.
Not imported trough Estonia but pcb is actually printed in Estonian factory.
I really liked you video but too bad you didn't end the repair. Maybe in future is better to wait to component to arrive and end the video before posting? Just a sugestion. I would like to see the device working :)
Don't you think it is the journey that matters more than the destination? But anyway I have a habit of publishing follow up videos, especially if things didn't work out as I expected so watch this space 😉
I actually have about 4 of those mag boxes all broken lying around
Richard, @7:10 there are 2 larger MLCC capacitors, side by side, just below the 3R3 value coil. The left capacitor looks like it has a crack in it.
it definitely looks cracked, +1
If you take a look at 12:13 you will see that 'crack' in the MLCC cleaaned off quite easily 😉 It looks like a small hair or something like that
No you didn't stun me. I have used that method before to find a shorted component
It's the way you do it is what matters. That's what she said😅
Where are you from? I hear Stoke-on-Trent?
Damn those finger hairs are going to cause a short 😂
Is your name Jim on FB by any chance ?
Which island ?