How to SAFELY use Voltage Injection to trace Short Circuits - Tutorial LER

[@DevilbyMoonlight]

Very good tutorial, one little trick I learned way back when trying to get out tiny SMD components quickly next to bigger components like electrolytics is to use 2 soldering irons, one in each hand to heat both ends at the same time..

[@LearnElectronicsRepair]

Hi Andy - yes that is another very good technique

[@NurdRage777]

Or hot tweezers soldering iron.

[@Zero_Ego]

Very cool. Thank you for spending the time teaching these techniques. Sadly some popular channels keep these pro tips only for their patrons and that can suck because we feel excluded. Everyone on KZbin is begging for money. It's getting very sad.

[@LearnElectronicsRepair]

Probably that's just a sign of the times. Of course if anyone wants to make a donation I wouldn't say no, but definitely no begging here - I'll just keep on making videos for all who want to watch them, regardless 😉

[@electronicsanta8149]

I’ve always paid the you tube premium fee to avoid ads and therefore paying my way and contributing via patreon or donation to Chanel’s you enjoy is what we should be doing Go make a video and see what’s involved

[@patrickcrosby3270]

I think this video has just saved me a load of grief, got an old imac and I thought the cpu was shorted. Think its worth another look now. Thanks

[@89Ssik]

Great tutorials, I learned a lot from watching you and Mr Sorin, after I finish this list i'm going to watch newer ones that you made, I took a sneaky-peak they seem to be bit shorter than these but I am sure great wisdom is put into them! From starring into pcb boards like monkey now after watching your tutorials I can finally have some basic understanding at least what is what and how its working, but unfortunately when it comes to circuits I find myself in deep water very fast... I do electronics on ground and I got used to use my legs as well, technically I came to precision like having 4 hands at this point can't work on table

[@dilanoclarke8114]

Thanks for the lesson

[@chongli297]

Really love the alcohol evaporation trick! Definitely a lot cheaper than picking up a thermal camera! I think one tool I would definitely invest in would be LCR tweezers. Much easier for measuring those tiny SMD capacitors!

[@Martin-ot7xj]

Hi there, it was one of your best tutorial videos. please upload more like this video. keep it up. thnx

[@LearnElectronicsRepair]

Thank you - I'll try to do more like this one

[@khaled_6962]

From Algeria 🇩🇿 thank you sir for this great video

[@LearnElectronicsRepair]

You are very welcome

[@waynerowland5050]

Excellent video mate. Really appreciate how you explain circuit design with the use of drawings, Only recently found your channel and glad I did, keep the video's coming 👍👍👍👍

[@LearnElectronicsRepair]

Thanks and welcome

[@johnantliff]

I'm a newby to electronics but eager to learn - I'm currently looking into a fault on a Enermax EGX850EWL and I've identified 2 x shorted Mosfets and a blown up resistor and a blown up optoisolator chip. My biggest problem is extricating the Mosfets (K2607) as the heat sink is massive with many components attached, so I'm attempting to remove one of the large transformers to give me room to extricate the fixing bolts. This is a beefy power supply and I think it's worth the effort to repair. Your videos are most instructive and my learning curve is steep and I suspect quite long. BTW I also have have a Pro'sKit SS-331 which suffered the same fate as yours in that the s/s tube moved withing the heating element but I have fixed it's position by making a couple of brass rings which I forced over each end of the s/s tube thus it does not now move when being "rodded". The user manual does warn about too much heat oxidising the lead free solder into a solid lump which I now (if it occurs) remove with a long 2mm twist drill instead of trying to hammer it out! Keep up the most enjoyable and instructive videos - John in NZ.

[@therealspixycat]

Very well explained! You could the component after taking it off from the board to make sure you measure almost 0 ohms

[@paulf1071]

Great tips in this video. Even though it was an old MB, was anybody else slightly uneasy seeing 5.0A pumped into PCB traces of unknown widths for so long??! It was probably ok, but with the current-injection method, the quicker you make the diagnosis, the lower the risk of cooking something. This is where a can of freeze-spray or a thermal-imaging camera would be invaluable.

[@LubosMedovarsky]

This video is so crucial in repairs that it deserves a lot more likes than it has.

[@knightwar3]

thank you for sharing this one so it's better to be safe with 1V if i want to check anything for a short circuit even on the main power rail

[@istvanzilizi6194]

Thank you for this video, this is a real tutorial where everybody is able to learn a lot!

[@Lucky_Red_Fish]

You sir are very impressive, you appear to be able to do this stuff in your sleep, bravo!

[@igorrizvic6008]

So basicly mosfets protect the consensators.....the coils dampen the frequeancy surrounding the cpu....to have less load on a cpu....higher voltage means more tdp with can actually put a 4ghz cpu on it.....without the dependancy....nice video....keep up the good work

[@Nworthholf]

It is always sad to see such a magnificent channel with so low subs count. So useful series!

[@LearnElectronicsRepair]

@Alkexander Moro The channel is just 9 months old and it takes time to build up subscribers. On average it takes a new channel 10 months or 22 months (depending which data/website you believe) to reach 1000 subs. According to that #LER is ahead of the trend as it took just under 6 months to get 1000 subs and another 3 months to get 2600+ more. Latest stats are saying +1100 new subscribers in the last 28 days. So it's not exponential growth but it is faster than linear.

[@Nworthholf]

@@LearnElectronicsRepair okay, I smh missed that the channel is _that_ young. The amount of quality videos looks more like 3+ years, and numbers are much more impressive if you take the real age into account. Anyway, your extremely detailed videos made my messy experience with repairing stuff much less messy, and things are making much more sense now. I was able to fix one of the boards where I wasnt able to figure out the issue before, and even got enough courage to order two cheap dead R9 280s to try and maybe resurrect one of them :)

[@LearnElectronicsRepair]

@@Nworthholf Yeah I'm a bit prolific with videos as I enjoy making them. It's really good to hear that I helped you to fix one of your boards, it makes me happy when I know I am helping people. Good luck with the R9 280s, come and join the Discord, we can chat about them there when you get them Learn Electronics Repair is now on Discord! Come and join the fun and let's fix stuff together, it's free. discord.gg/vam6YC8vwU

[@allanpatterson7653]

The +12volt line supply's various Buck convertors could be +3.3 or +1.8 if you broing up one of those lines that are low the components that are leaky will get quite warm.

[@jotnarymir1393]

Best tutorial

[@scriptguru8]

Great video and great channel. Thank you for creating this educational content. It was a little hard for me to understand you (English sounds quite different depending on a location), but even automatic subtitles from KZbin helped. An interesting alternative to the isopropyl alcohol is a "rosin atomizer pen". It allows you to create something similar to "rosin frost" on a part of a device. Once some component is getting hot, the "frost" melts on it, and it becomes very apparent where exactly the short is. But you still have to inject safe voltage at current enough to heat up the part.

[@afolabiakinniyan2257]

i really really learnt someting new today, thanks man

[@robertisaacs5122]

Loved This

[@tinagladu3744]

great learning videos

[@NewbFixer]

Amazing! Thanks for sharing your knowledge. Im surprised that wee cap took 5 amps 🤣

[@sunilshahi875]

Thank You so much for sharing knowledge Sir

[@attiliofiandrotti]

Nice video, by the way I was baffled to find out the culprit was that tiny cap: I would have put my money one one of the switching transistors

[@LearnElectronicsRepair]

MLCC capacitors (the little SMD ones) are very prone to failure by mechanical shock or thermal cycling - and when they fail they almost always go short circuit.

[@anthonydenn4345]

Nice job. It's crazy how something that costs less than a penny can disable a motherboard. That cap was pretty hot. Would of probably went up in smoke if it was able to draw any more amps.

[@LearnElectronicsRepair]

Oh for sure it would have burned up if I had a more powerful bench PSU!

[@John-we7jx]

Thanks

[@JBpremiumsignals]

nice video sir :) i myself is a tech just starting to learn about motherboards, can you make a video for debug card sir on what the codes are for and full tutorial on how to use debug cards? appreciate it :)

[@daz41262010]

great video on voltage injection :)

[@ziadfawzi]

Thank you so much.

[@weerobot]

Outstanding Videos...

[@quanhoang2091]

thank you so much Sir! i am looking for this , it is great.

[@AmilaNadeera]

Wow it is christal clear. Thank u so much.

[@bineshchauhan8713]

Thanks from india

[@enriconapolitano4321]

Very good tutorial, thanks

[@LearnElectronicsRepair]

You are welcome!

[@laptopDoctorKZN]

clear cmos -3.3 also check the voltage on the bios pnin

[@carmelorossitto7084]

Very clear explanation and procedure. Thank you for sharing it. Does it also apply to find faulty chips, e.g. a screen having no backlight, in a motherboard turning on?

[@Yreq]

I"m watching this video on my quad775 PC on with DDR2:p Very interesting subject. Thanks

[@Franklinveterinarycenter1of4]

I guess the older mother boards you can get away with 1.2 volt and 5 amp regulated power when there is a short to ground. On the more modern mother boards, the recommendation is no more than 0.9 volts and 2 to 3 amps depending on where the short is with regards to CPU OR GPU. most repair specialist would have replaced the mosfet and removed the capacitor😁

[@krzysztofkoch3426]

Thank you :) 🍺

[@slifox2752]

A thermal camera would be a good diagnostic tool in this case…

[@Adrian_Finn]

Learnt a lot on this one, thanks for sharing.

[@LearnElectronicsRepair]

Glad it was helpful!

[@danilopereirar]

brasilian student learning about voltage injection

[@gazzacroy]

very interesting video, cool :)

[@markwhitfield5412]

Try some blue tak to hold tiny parts, if u ping that across the workshop, good luck finding it, been there done that failed...lol

[@LearnElectronicsRepair]

Nice idea - I'll give it a try. Thanks.

[@darrenstrathdee7425]

I Use the mechanic vc04 personally.

[@jessstuart7495]

I'd be very tempted to just stack two 4.7uF caps.

[@ronb6182]

Yeah power up and use finger. If the part is hot replace it after going through all the circuits. You may have other parts shorted as well. 73

[@RectifiedMetals]

Where can I get a bench psu without the protection to inject voltage? I see a lot of chinesium made “short killers,” with horrible reviews. Every PSU I have had just protects itself, some at loads at only 68 ohms and below. Can I disable the short protection in a bench psu. Maybe a newb question, but my experience is in older electronics.

[@jozsiolah1435]

One simple way is to use a 3 v motor and a 1.5 v battery. That won’t effect the components.

[@sparky150875]

Hi Richard, I know this is an old video and you may not see this but I have been injecting voltage into the 3.3 area on an xbox one. I started low and worked up but end up at 3.3v and 3A. Had 3A drawing but not a single thing getting warm. I think it could be southbridge because of where a few shorted caps are but don't understand why nothing is getting hot when it's pulling 3A. Any advice would be greatly appreciated as my next step is removing the southbridge. Love all the content by the way, very educational.

[@bigbite9804]

Please sir related VRF air conditioner PCB upload some videos .

[@m.a.4795]

Why do they put electrolytic cap. in parallel with smd cap. ?

[@defaultuser0856]

Hi there, i bought a power supply for mobile fixing, and today i found that it has a short detector that shuts down the power supply when short is detected, can this be used to inject elctricity into a circut to find the broken part ? Since the elctricity that's going in is transforming into heat, so i guess it should not turn off right ?

[@therealspixycat]

Can you explain how measuring in diode modes exactly works?

[@irishguy200007]

at 6.30 where is the negative probe of the meter connected?? Ground on board??

[@tunkunrunk]

I didn"t know you could find a short by measuring ATX connectors on a motherboard

[@davidhollfelder9940]

Maybe try thermal printing paper?

[@donovanpl]

Why are there 2 MOFSETs configured on the low side?

[@erdum]

my mother board suddenly gives me BIOS corrupted or missing error it was working last time nothing happened, I tried to find short but nothing is short near BIOS, just 14 ohm resistance which is from the CPU load I get to know in your video. I thought that 14 ohms is the short near BIOS causing BIOS error but after your watching your video 11:50 I am desperate how to find what happened with my mother board optilex 760.

[@AB-yu2tj]

My power supplies current limiter prevents me from injecting voltage in a short. What do you suggest

[@donnang8763]

Hi, do you have any video on asus z240ic aio motherboard?

[@grindererrofficial3755]

Hello Richard,So the point of safe method is adjusting Voltage up ( max handling Voltage for component) for most vulnerable/fragile component at shorted line with maxed amperage ?

[@LearnElectronicsRepair]

Basically you need to consider voltage rails derived form the one where you want to inject voltage. Inject a voltage no higher than the lowest derived rail (about 0.7V is safe for any GPU and 1V on motherboards) Then check for any voltage 'leakage' from the injected supply to those derived rails (which are usually buck converter coils but could be LDO regulators) If you can't get enough current in to warm something up, and you are happy that there is no voltage getting through to sensitive low voltage circuitry, then feel free to crank it up

[@grindererrofficial3755]

@@LearnElectronicsRepair Yes Sir, and for more detailed desription.

[@mugabirapaul8653]

Hello sir I have laptop motherboard but the power coils start to heat up slowly yet it has no glitch and has Good output. Please sir what makes the power coils to heat up

[@abdaimegaming2679]

i bought a used motherboard and when i turn it off and unplug it from the wall , next time i plug it to the wall it turns on without pressing the power button and doesn't start , untill i unplug it from the wall and plug it again and press the starr button ,after i start it it gives me an error that the rtc is reset and i press f1 and it restarts and then starts normaly , i changed the cmos but i still have the same problem , but after i inspected the motherboard closely , i found out that one of the vrm mosfets is missing , the mosfet missing is a r172a transistor, my question is , is it ok to use the motherboard with that mosfet missing, and can the error of the rtc caused by the missing mosfet or it is something else that i haven't found yet

[@zubairhanif6735]

Interesting technical experience you have where can I get this voltage injector?

[@LubosMedovarsky]

It's otherwise known as "thick wires" and "strong power source".

[@scriptguru8]

It's just a "lab" power supply from Amazon or other store

[@twonirwin4056]

Should be using a thermal camera

[@playerraxis]

Is it safe to inject more than one volt in this method can 3 or 5 if not 12 volts be used however the method that I have to inject the voltage is to DIY a ATX power supply into a test bench power supply because I don't have a voltage injector or a test bench power supply like yours.

[@LearnElectronicsRepair]

No you need to be careful here - never inject more voltage than the device under test can handle - because whatever is short circuit (for example a capacitor) could suddenly burn out and go open circuit and then your power supply will send the full voltage into the device and if it is for example a GPU or something similar that requires a low voltage it will also be destroyed. Which I expect is not what you wanted to happen

[@playerraxis]

Thanks you've been a big help

[@playerraxis]

Oh yeah keep the content coming there very helpful 🖒

[@MichaelNichol]

Video card Repair, where can i send my card to be repaired, sense i can't buy one ??

[@NOMADCREATIVESOLUTIONS]

I have a motherboard where the fan control in the bios isnt working.. it just runs the fans at maximum.. I can see what I think are like voltage regulators near each fan header.. is it likely its these that are gone or any other advice as to how to restore the fan control?

[@LearnElectronicsRepair]

What motherboard is it? Model number...

[@irishguy200007]

What's the maximium current allowed for this method? Please don't respond with how long is a piece of strong. is a power supply with a mix output of 2.5 Amps any good??

[@jjg2753]

Excuse me, may I use battery to do the short circuits finding by adjusting it using potentioner?

[@LearnElectronicsRepair]

No definitely not - the potentiometer would just burn up.

[@jjg2753]

@@LearnElectronicsRepair Oh no, i forgot the high current goes into this potentiometer first. So power supply is a must equipment.

[@geoepi321975]

Hi , can you tell how to determine pch short

[@LearnElectronicsRepair]

Well... if it gets warm when you just have 5V Standby, it is definitely short/faulty If you measure the current drawn from the CMOS battery without a psu attached and it is more than a few microamps it is most likely faulty You can measure the resistance on the little capacitors that are ofen mounted on the substrate of the PCH - if any of them are short it is probably faulty

[@geoepi321975]

@@LearnElectronicsRepair thank you sir

[@edwardlacson2592]

Comfu dead shorrted not working c0u or gpu duty

[@SFInspector2211]

If I can only I could understand what he's saying

[@jiceli5713]

you accent is very hard to follow at certain times

[@khawalataghla5885]

حسينة محمد مولود مبارك وامي فرحان الحسين الهامل 1970 1912 و2امي فاطمية وابي الركيبي الهامل كنا ديرنه الكورة الكدام فاطمية الزهرة منت محمد الرسوال الله الله الله هذا لاميسينا فيها لابغراب ميسلاح لايجيلي اجيل الكرامة والحنين والعطيف لاحتيريم صحيح كلام الله الله الله اله اله ياخلايكم نقولاي لاجيل اولادينا وامناتين الكارام والله الرحمن يالرحيم عبيدو الله الله اله

[@khawalataghla5885]

احن موسلامين ومسلامية وهل المحيبة يا الله والنبيني محمد والكارامية ولاحتيرامية الله والحنينية والله يدر هامن في الجيل البليد في العالم والمحبية ابين امين ابين وااخواتي واخيلي واخليتي والزيريني واخنيي لاسلامية ولاسلايميتي الله الله اله مكين الدين مواره الرجال البيت الله الله الله في العالم الله السماء 7 ولارضية 7 الله الله الله ياحفظكم وانصركيم علي القوام الكفيرين والجريمين والجريامات والحقدات والحقيدان الله الله الله ياصميح لاجميع لاسلامينن ولاسلتميت الله الله الله

[@imageer]

If you could talk in understandable English, that would be great.

[@jamestonge5066]

Could be a lot better but to much rambling and mumbling I can't follow him.When he stops talking its like a crying child finally going to sleep, yeah

[@LearnElectronicsRepair]

I guess not everyone is going to like my style of making videos.