How to test an SMD Mosfet

FYI!! The same info applies to the smaller mosfet next to the big one I tested!
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[@chasefournier]

How to Solder Like a PRO kzbin.info/www/bejne/eqaWnKKMrdF0edk

[@NewbFixer]

Hi Chase been watching your videos. Apart from the gate being shorted... If i could add a few tips which perhaps will help your viewers and maybe help you too. If the smd mosfet starts with an odd number its P-Channel, if it start with an even number its N-Channel, This is only for smd mosfets. Also all mosfets have a diode built in called a body diode. P mosfets have the diode Drain -->|-- Source and N has the diode reversed (D --|

[@chasefournier]

Thank you!! I pinned your comment because it gives an indepth understanding of mosfets. I really appreciate the feed back, my knowledge in electronics is large and small in different areas, so I wanted to give my knowledge on what I knew about testing them. Any corrections are appreciated!

[@NewbFixer]

@@chasefournier your welcome, no corrections just sharing the tiny bit of knowledge i have on smd mosfets.

[@JacobDubs]

@@NewbFixer Thanks for adding this explanation. It really helps those learning (like myself).

[@NewbFixer]

@@JacobDubs Your welcome buddy.

[@sadrii8313]

This is very helpful!I was wondering what the meaning these dots? everytime i look on mosfets.

[@sillywwabbit]

Got the Source and Drain reversed. Source is next to the Gate and Drain is on the other side. You can also set your meter to continuity mode and place the positive (red) probe on ground and the negative (black) probe on the gate. It should not beep. If it does, its shorted to ground.

[@calvitocalvon1711]

Hey dude where can i contact you for more knowledge?

[@_mylastname]

Clear, concise, to the point and now I finally understand. Thank you

[@015diesel]

This video cleared up a lot of confusion for me, thanks so much for taking the time to share your knowledge with us! Thanks again 👌

[@rwbeezy1139]

I have watched videos from about 15 other people trying to teach this and so far this was the best explanation. Thank you.

[@chasefournier]

Thank you! ☺️☺️

[@frankfournier5183]

He got to love that voltage injection tool and thermal cam! Great video keep up the good work!!!

[@NavyPanther54]

Thanks dude! By far the quickest and most easily understandable explanation I could find. Trying to fix a 1070 with a short, and I found one burnt mosfet. But upon checking the others, I did find two more shorted out.

[@chasefournier]

That's fantastic! Glad my video could help you! Also, just to rule out everything, inject voltage and see whats gets hot. It's not super likely that multiple fet's would blow all at the same time, but i suppose there is a possibility.

[@NavyPanther54]

@@chasefournier Just an update. Tackled the GPU again finally. Originally there was 1 blown mosfet that I butchered and removed. Still would kick the cheap PSU I had for a test bench. Followed your tutorial again, found 7/18 that seemed to be shorted out. Managed to get those off without damaging the board (proud of that), and now my test bench doesn't kill itself. No screen though, but I can't be sure it's the GPU still or the test bench, as the mobo and cpu are also not known to be working or not. But progress I guess? I think the board is toast anyway. After getting all those Mosfets off, I checked the resistance between the little pads left where the pins for the mosfet would be. And they're still reading 1-2 ohms. Sooooo google makes it sound like the copper layer inside the board must have welded itself together. Kinda funny how the one noticeably blown mosfet reads 10k between the pads like the other good ones though. Anyway, thanks again for the video. I had to come back to it again after not trying for a year or so lol.

[@kieferonline]

Great video! Straight to the point, clear, and some very useful techniques. A perfect video!

[@chasefournier]

Thank you! 😊💯

[@cletusnze4171]

Excellent! You made it look simple and straightforward!

[@chasefournier]

Thank you! 😊💯💯

[@NerdThingsAndMore]

Thanks for the info

[@Martin-ot7xj]

wowow , , your Explanation was very clear & simple, i highly encourage you to upload more like this video to find short mosfet & component circuits and laptop mainboards for beginners. thankyou. keep it up

[@markmurphy9280]

Thank you for the clear explanation, subscribed.

[@samuelmagilocusts2870]

Very helpful video! I’ll definitely be recommending this one to people who ask me how mosfets work’

[@TheHalo14aus]

Thank you, very helpful and easy to follow.

[@repsolal]

Nice job Chase, good clear explanation

[@chasefournier]

Appreciate it 😊 I don't think of myself to be an expert in mosfets by any means, but to have the general idea on what to look for using your multimeter I think this is a good resource for repair 😊

[@ishigamiyu1991]

Thanks I'm repairing my water damaged RC ESC. This helped a ton!

[@chasefournier]

Glad to hear! Good luck!

[@maxwarfield6699]

Simple and informative video - Kudos mate!

[@chasefournier]

Thank you!!🙏💯💯

[@user-kc2hx7bi7q]

Nice going! keep up the good work

[@alejandromartinez7327]

Awesome video!! Very helpful!! And i also bought that voltage injection tool and within the hour that I received it, it burned out!!! Back to injured gadgets it goes!!! 😕

[@tylermeehan8628]

Honestly the first video I’ve seen on how to test mosfets in detail

[@chasefournier]

Thanks man! 💯💯☺️

[@ripe_apple]

nice video, keep up the great work..

[@hairulole]

Great tips Sir 👍🏻

[@chasefournier]

Thank you! :)

[@bobbysantiago5783]

Awesome. Thank you.

[@bytemecomputers5317]

Great video!

[@chasefournier]

Thank you!!

[@ahmedtwahir]

Very simple and to the point

[@chasefournier]

Thank you!!! 🙏🙏🙏💯

[@ZulhamS]

thank you bro

[@Saf_R]

Brilliant tutorial

[@chasefournier]

Thank you!! 💯☺️☺️

[@Mrghj3656]

Thank you

[@webcorpit8314]

Very helpful thanks

[@chasefournier]

Thank you!

[@luisadolfolopezvelasquez3376]

Thanks a lot Chase, thanks a lot for the video I´m from Nicaragua, very useful, please continue doing that

[@chasefournier]

No problem man! Glad I could help!!

[@luisadolfolopezvelasquez3376]

Thanks @@chasefournier

[@luisadolfolopezvelasquez3376]

The gate is always with the source and drain are the 4 pins together in that way I never forget where is the gate and source

[@Zackprojects]

very helpful

[@josearrasola7236]

Hello sir , nice job that’s one thing I don’t have is a thermal cam ! I work with a team of six other staff and not one of them have a thermal cam ! 😂 but kudos to you

[@a13Banger]

I've been scouring the interwebs and have yet to find a good video showing how to use a multimeter when diagnosing a potential circuit board issue or even just how to use it to verify components are good. I'd love to see a video from you in particular, that explains how to use it like "To test this capacitor, turn the meter to this, use the red/black probe for this or that and place them here.. etc.." I am a new to this but already have a great work bench setup and have gotten good at soldering desoldering through hole and SMD components. However, I am lacking so bad in understanding how to use the multimeter in relation to a given PCB. Often channels will verbally say "meter in continuity mode or this or that mode" and then maybe you'll see just the metal tips to the probes touching somewhere.. I would just love some insight onto which probe is where and why etc.. Anyway, love your videos!

[@xhuljan11]

Thanks 👑

[@chasefournier]

You’re welcome 😊

[@Martin-ot7xj]

Hi , we must put multimeter on continuity mode or diode mode ? thnx

[@scubaron2293]

Good job,,,,!

[@chasefournier]

Thank you!!

[@kevinhancock4064]

Great video i have what appears a shoryed mosget 8 pin but they vary in vpltageceyc but are the layout all the same ? Mone is ny3p016Bs8 P7081AF ty in advance buddy

[@stevendavid9430]

Hi Thanks for the vid..but i hv a imax charger and its has a mosfet 4407 weirdly i have a connection or a short at drain and gate..i hv tested all parts of it n its shorted at that. But the chip is still on board i dont hv a rework station to remove to test. Based on ur vid I DONT HV A SHORT AT source n drain..😅😅😅😅 is there smthing wrong im doing?

[@kennedyramish4660]

wow, that is cool, i have a problem in motherboards, whats is the hardware problem that makes a computer to restart over and over,

[@andrewdewar8159]

Hello, I think that the 4 pins is the drain and the 3 pins is the source. It always confuses me that the Source (usually the negative end) and the drain (usually the positive end) are the same whether its a P channel or an N channel mosfet. It confuses me because in a P channel the charge carriers are positive holes yet the source is still the negative end and the drain is the positive end for both N and P type mosfets. By the way, I have seen on other videos that if you happen to touch the gate of a mosfet, its enough to charge the gate so its conducting, so to test the mosfet you should short gate to drain and check there's no conduction then. For N channel the + goes to drain and the - goes to source. Then you touch + onto the gate and see if it now conducts. For P channel you put + to source and - to drain. If the gate is discharged it should not conduct. Then touch - to the gate so its -ve. Now it should conduct from + source to - drain (opposite to an N channel) I got this off of youtube so I hope its right.

[@aarongray503]

Question, I am also working on a xbox 360 motherboard. Won't power on. Was looking at mosfet u5a1. Got 5v going in on 2 legs on one side and only 3.3v going out on 1 leg on the other. Is this normal?

[@Maveric193]

Many thanks for this video. Please forgive me if am only in early stages of electronic testing, very early stages. I actually thought a mosfet had 3 legs and did not resemble more of a chip like the ones you tested here, but I can see you still only have 3 separate points of contact. But how do you know which pins to test on a 3 leged mosfet please.

[@chasefournier]

No worries! It's basically the same thing, there's the Drain, source and gate on your 3 pin just like the one in this video. But I'd suggest checking the part number whatever mosfet you have and determine if it's a NPN or PNP. And then of course the data sheet to see what pins are which.

[@gelb_0139]

Very helpful video!! 1+ sub

[@chasefournier]

Thank you!!

[@yoelpittol]

Excellent! Thank you! Do you know maybe what’s the proper resistance between negative and positive pins on the power supply connectors in the main board of a Xbox one like yours?

[@chasefournier]

Usually in the several thousands to millions range. 12v to gnd ohms mode.

[@jimw7916]

How do you know that the short might NOT be in the MOSFET? ........ its possibly in the driver that drives the gate.

[@tompo0071]

WHAT WHAT DIRECTION DO CURRENT ENTER MOSFET?

[@DeepakKumar-lv4te]

I've seen a video that talks about how simple it is to charge the mosfet with even a bit of skin static and then the cont. test shows up as a short. But it isn't , it needs to be grounded first to remove any postential charge before testing.

[@DeepakKumar-lv4te]

Hi, thx for the vid. Do you know anyone UK based who can do repairs? London preferably. I've got a gaming laptop that's booting and loading fine but then shutting down after about a minute with the fans raging. thx.

[@berlinjubel763]

Hi ...I love to see more videos on how to troubleshoot an industrial machines cards fill will surface mount capacitor..thank you

[@chasefournier]

kzbin.info/www/bejne/qKimmoeCq7mZbM0

[@lightshine6044]

4:17 can you tell me brand and model name of thermal camera you are using?

[@journaldelor626]

Un bon modèle : InfiRay P2 Pro + lentille macro existe pour Android /IOS le prix environ 230 € sur un site chinois B******d

[@michaeldaly3166]

Thanks, but how do you correctly identify which side the Gate contact is on?

[@chasefournier]

Typically with these mosfets the gate will be the single connection by itself.

[@aboabdrahmanaziz8752]

Good

[@Martin-ot7xj]

please make a tutorial video about how to read laptop schematics. thnx

[@spanial]

Awesome video but how do you fix it? do you just replace it with another mosfet?

[@chasefournier]

Yes.

[@yakine13]

Hello, I have a Lenovo y520 with a GPU burning right at the boot and thus shutting off immediately the Laptop Fan does spin, keyboard get lighten up and then it shut down. I suspect the laptop to go into safety because of the GPU short ? I don't know where to start but there's several 330 Diode shorted. As for mosfet next to the GPU, many of them are shorted between source and drain, but none with the gate. Thanks for your advice

[@chasefournier]

Usually due to low resistance to gnd the source to drain will show short but isn't actually shorted. However if you inject voltage at the drain you will know for sure.

[@lynchdemartini]

Any mosfet injected voltage will reveal the overheating mosfet?

[@chasefournier]

Voltage injection will typically show a shorted component. It really depends on the circuit.

[@randonnaidoo2592]

Hi where do i get a voltage injection tool, i did hear about these methods

[@chasefournier]

You can use a DC power supply, or you can buy a voltage injection tool at northridgefix.com

[@nayefalkurahi3357]

Does that apply to the little mosfets to? like the one to the right of that one your working on? i have an asus gaming rog502 i believe and man i have a bunch of mosfets that read like low ohms between drain and source or gate and drain .. thats usually bad to right? i heard any mosfet should be in the thousands and up

[@chasefournier]

Yes it typically does. Honestly, it depends on the voltage rail. Like if it's a really low voltage rail typically it will have low impedance to ground. So it will show in some cases like 0.5 omhs to ground, and it's not shorted. But like if you have a higher voltage rail like say 3.3v to 12v it should be like 500 ohms to like several thousand. Always test gate against the source to test if the mosfet is bad. But typically, you will see on the drain if that rail is low, it is likely shorted. But because of low impedance sometimes it's not shorted. There's so many variables, you'll have to play it by ear depending on the board you have that your troubleshooting.

[@nayefalkurahi3357]

@@chasefournier ok so mosfets , coils and i think diodes are reading like 5 or under ohms near the gpu / cpu , thats normal ? Also i have a rog 502 loaptop.. dc jack mosfet had short between source and drain but laptop still turned on , but wouldnt charge.. so guys at badcaps told me to change mosfet so i did.. but no power.. tried 2 mosfets.. Put back old mosfet still no power ... man i think those mosfets burnt something.. are these 2 mosfets the same ? nikos pkch288 uuddpo10c ( replacement ) NIKOS PKCH288 GUD201701 ( original ) ?

[@chasefournier]

@@nayefalkurahi3357 if you have a short on drain, it's likely that that power rail is actually shorted. You will need to refer to my video on voltage injection. basically understanding how to find a shorted component. kzbin.info/www/bejne/qKimmoeCq7mZbM0

[@Stry-Glitch]

tips mate : Drain start with "D" the 4th letter on the alphabet. 4pin -> drain

[@chasefournier]

King 👑🙏🙏

[@Stry-Glitch]

@@chasefournier No u !

[@trevorjames5493]

What if the three pins besides the gate are not on their own island and they're connected to the same island as the gate ?where do you test it then? or are they always on a separate Island from the gate?

[@chasefournier]

Drain is 4 pins Source 3 pins Gate 1 pin

[@trevorjames5493]

@@chasefournier thanks for the quick reply yeah I know that part but I meant on the same part of the board so they shouldn't be touching like you said so I was wondering what if they were solderd to the same part on a board ? Or does that never happened like they never solder gate and source to the same pads cuz that would defeat the whole purpose right

[@pierrekiefer21]

The gate is the control pin to turn the MOSFET on and off. It is always a separate trace.

[@rickpontificates3406]

Actually, I would use the diode checker rather than continuity.

[@j.lietka9406]

This is helpful! Should you have zero ohms across the source & drain? Thank you 🤓

[@chasefournier]

In this video, the drain and source are switched (my fault). The source is the 3 connections and it is gnd. The gate shouldn't be low resistance to gnd.

[@j.lietka9406]

@@chasefournier no probs! But if you ohm read across the source & drain, you should get either extreme high resistance or an open? If you have time, try a sound Church of Christ (not Mormon) thank you. If a mosfet is open (power on) can you jump across the source & drain? Thank you

[@chasefournier]

Drain is the positive side and source is negative. On an Xbox board like in this video, drain and source will show show short, but is low resistance to gnd. In some cases there's a possibility it could be shorted at the drain. Just need to check OHMS and Diode readings

[@j.lietka9406]

@@chasefournier ok thank you. More for laptop m/b use.

[@IPridek]

You are a fucking beast , Thanks bro

[@chasefournier]

You got it man!

[@miguelmichel68]

How to find the shorted mosfet= comment trouver le mosfet en court circuit

[@chasefournier]

kzbin.info/www/bejne/qKimmoeCq7mZbM0

[@Martin-ot7xj]

please make a tutorial video that how to inject voltage to the mainboard to find short circuit .for example to which component we can inject the voltage exactly. thnx

[@chasefournier]

kzbin.info/www/bejne/qKimmoeCq7mZbM0

[@mrmc55]

🙏🙏🙏 I got something

[@X-OR_]

Mosfet really turn me on

[@chasefournier]

Nice

[@andrewdewar8159]

Me too its a FET-ish.