How To Test A Power Supply Unit (PSU) With A Digital Multimeter | Advanced Troubleshooting
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- เผยแพร่เมื่อ 2 ส.ค. 2024
- In this youtube video tutorial I show you how to test a psu with a multimeter or how to test a power supply unit using a digital multimeter. This is an advanced troubleshoot tutorial. There is a paper clip test you can do to check if a power supply is dead or not. However that test only checks for power but not for correct voltage.
First you need to test for AC Voltage coming from the mains plug. Next you need to test for DC voltage from each of the pin on the power supply unit.
Standard ATX 12V power supply units can be either 20 pins or 24 (20+4) pins. The method is the same for each.
This video is also a stand alone tutorial as part of a longer Troubleshoot series, see details in the video and below.
Time Stamps:
00:36 Troubleshoot Series Intro | Desktop Pc Computer Not Turning On No Display | How A Computer Works
• How To Troubleshoot A ...
00:44 Test A Laptop Charger Adaptor With A Digital Multimeter
• How To Test A Laptop C...
00:50 Troubleshoot A Dead Computer Pc No Power - Desktop PC Computer Not Turning On At All Easy Fix Repair
• Troubleshoot A Dead Co...
00:55 The paper clip test
001:43 Power Supply Unit Replacement Under 2 minutes Challenge
• Power Supply Unit Repl...
01:55 Mastech Digital Multimeter MS8268
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02:53 UK AC Voltage Range: 216.2 to 253V
www.nottingham.ac.uk/etc/guide...
03:02 Tolerance of -6% to +10%
04:42 Turn a Computer Power Supply into Bench Power by Jason Poel Smith
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06:00 Laptop No Display Black Screen Blank Screen On Startup | Best Guide How To Fix Troubleshoot Repair
• Laptop No Display Blac...
07:26 DC Volt Tolerance
Red/Purple: 5V +/- 4% = 4.8 to 5.2 V
Yellow/Blue: 12V +/- 4% = 11.52 to 12.48
Orange: 3.3V +/- 4% = 3.168 to 3.432
10:18 How To Take Out Or Remove A Motherboard From A Desktop Computer Case | Breadboarding Easy Mode
• How To Take Out Or Rem...
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I have assembled so many desktop computers and troubleshooted laptops, today, I have learned a new lesson from you. Your demo is outstanding. Everything is very clear. I felt as it is done in front of me. Awesome Sir, Thank you...
I second this comment. Very nice. Exemplary vídeo.
Yep I would just process of eliminate and get to PSU but this helps.
1. connect pin 15-16 to turn PSU
2. connect black needle to pin 24 and red needle to pin 13,14, 21,22,23
3. connect black needle to pin 14 and red needle to pin 1,2,4,6,9,10,11,12
Cool summary!
@@HealMyTech1 thank you a lot for the tutorial
One question: the blue colored wire (-12V) reading is 11.3V for me, every thing else is good even the cpu, gpu and molex connectors. Does that mean I need to replace the PSU?
Just a correction to call out on point# 3. It should be Pin 15 for ground instead of Pin 14 which is blue
When I do the following;-
1. connect pin 15-16 to turn PSU
(all Ok)
2. connect black needle to pin 24 and red needle to pin 13,14, 21,22,23
(Ok- all is good)
3. connect black needle to pin 14 and red needle to pin 1,2,4,6,9,10,11,12 (WTF ??)
The First set are spot on; but the 2nd set Are either 3x the listed Voltages (1 & 2 supposed to be 3v but are 15.57..v), and (4, 6 & 9 supposed to be 5v = but are 17.4v) & in the case of 10 & 11 they are near zero volts at 1v? or something;- ( '1 . ) .
And next, the 12th pin (supposed to be 3.3v) is 15.6v or so
Looking inside the PSU is relatively clean and looks perfect.
PC was running fine... but PUBG kept crashing halfway through the game. Then when I re-booted after the BIOS it went dead with one white underscore on a black screen. So, assumed CPU or GPU, but then wondered 850W Platinum PSU made in China maybe at fault. Wondering if i7-4770 CPU could have caused it?; or even TUF Motherboard? Or Strix GTX1070?
Hai indonesian
Thank you so much for this video. It's been over 20 years since I worked as a Technician. You reminded how to be one again. Pointing out the the Power On jumper did it for me. Appreciate the safety tips as well.
It should be noted that you can sometimes have failed power supplies that output at a voltage that's within tolerance with no load on the voltage rails. While it's more common that a rail will just outright fail, I have had instances where a PSU will output the correct voltage when measured, but when loaded it drops down to next to nothing.
What I do the mitigate this is to put a modest load, say, a 20w incandescent lamp or a resistor on the rail I am testing and then measure voltage. This will yield a more reliable measurement when testing for a failed supply as it should also factor in how much voltage drop you get on the rail when it's under load.
Additionally, a time-saving trick: every wire in the PSU is grouped by voltage on the output section of the supply's circuit board. This means, that unless you have a multiple +12v rail design (which can be seen in higher end power supplies), that a +12v on your EPS+12 connector and a +12v on your SATA power / MOLEX / FDD connector will be connected to the same point on the power supply, therefore should have continuity between the two wires. For this reason, I tend to simply test one wire from each voltage rail. Unless it's a multi 12v rail supply and I don't know where the wires are allocated, then I will test all of the wires with a load across my probes to confirm that all rails are working properly.
Great video dude! As the start I didn't even notice the other person in the video. When the hands moved I was like hey! Hold on a minute 😅
This is a good intro for entry level troubleshooting for a PSU, but what I would call "Advanced Troubleshooting" would be testing the voltage lines under load, which is a little more difficult. As a PSU could appear to be working just fine until you get it under an extensive load like in a video game or rendering session whereby the PC would restart due to a drop in voltage (most likely on the 12V supply) from a lack of current, measured in amperes, and is otherwise not sufficient under such load.
How does one do this this?
@@SuperKiki93 Are you seeing my post? I can't see my comment wtf, do similiar to what he is doing but under load you can use the search watch?v=ZiYFwjdh_lE
I just know how much my various hardware consumes so when I bench test a PSU I just choose the hw based on how much 12v amperage I am trying to load up on the PSU.
Great video, very informative. Been a builder for a while now and just started making my own cables. Came in handy when testing my work! Thanks!
use another working pc for 5 minutes to make sure it is working.
Good videos, straight to the point and very informative. Thanks !
Thank you sir! Just tested my first power supply. They explored a little further after the confidence of this video and looked up and tested all the parts on it as well.
Thanks for the great video!
This was a very helpful video. Helped me and my son to trouble shoot effectively a non working PC that he has assembled. The problem was that the 24 pin connector had no white wire. We could find that out easily. Thank you for this great and useful video.
I think it's supposed to be that way. Mines the same way. There used to be a -5v white but apparently they ditched it in '03
dude for like 89% of the video i thought the black hand sweater thing was like an automatic weird unique prop holder. it was moving erratic an creeped me out. but when you told it to hold this and it lurched forward i realized it was a humanoid.
I love the thought he put into making this a good video. The humanoid kept things moving and the black gloves keep focus on what is important
Thanks for the video, this helped out a lot when I was troubleshooting a new PC build.
Thanks! Excellent video. I used this method to make sure a psu wasn't faulty, it wasn't. Turns out disconnecting absolutely everything from the motherboard and jumping the clear CMOS pins brought the PC back.
This was perfect, exactly what I needed to narrow down my problems. My power supply is definitely working!
Very well done! I tested the same PSU; so this video was perfect. Thank you.
Glad it helped!
Good tutorial, helped me through the process without doing injury to myself or my computer and happy to report my PSU is 100%. Thanks!
Great video and thank you so much for it. Lucky me found it too. Ill just echo what everyone else said. Even in a quality tech school you dont get it this easy and precise almosat like one on one instruction. . The pinout charts were beautiful. Now the PSupply im only 20% worried about i can test instead of testing it first blind with the new pricey board and processor i just installed. Thanks guys. Edit to add: Just finsished the test exactly as shown and voila i KNOW i have a 100% power supply on all circuits...nice!!!
Very well explained. Thank you. Learned something today 👌🏽
Hey King, you dropped your crown! Thanks for the detailed instructions on how to check PSU!
Thank you, brother! Everything worked exactly as you said it would. Very Helpful.
I like the consistent uploads, great work
Thanks for the video! Keep up the great work!
very informative, thank you :)
You have been very helpful, knowledgeable, honest and practical. Stay blessed
Our PSU was great, the problem was with the Power cable. Thank you for a very informative diagnostic video.
You're welcome!
The power cable can cause issues for the psu??
@@corndogers564 Yes. The video shows how to test the cable. We had a faulty one that was providing lower voltage than the PSU required. Changed the cable and the PSU was fine
Exactly the kind of video I was looking for. Gracias!
Thank you for this concise instructional video! The diagrams and step by step process helped a ton!
This was easy and fun. Great content! You should add a pinout sheet in description. I used one to test my CPU and PCIe cables.
Best turorial I've seen, easy and detailed. Thank you!
Very easy to understand. When I test a PSU, I also test all other cables.
Thank you for your service sir 🖖
This Guy saves me to My Test 2 Practical and now I'm Comfortable ☘️💯
You are the top man and the first go-to when I need advice - cheers 👍
Thank you so much for this! Very helpful
Excellent. Thanks. My PSU is good.
Thanks a lot for this great tutorial : very good step-by-step explanations.
You're a champion, thanks so much for the video, was super helpful
Great help/ instructions!
A lot of great info...
Very clear and useful tutorial thanks
Thank you so much while i know these things but your video is excellent and so detailed
Thank you for appreciating!
Thank you my friend, your video was a great help. Very clear and well presented. Just one question though. Shouldn't we also be testing the 8-pin CPU power connector of the PSU?
yes that as well. There is schematic for it in your motherboard manual if you built a pc yourself. else you can find tons online and just cross check like this vid.
Nice job with teaching.... One thought for doing this alone (We all don't have a lovely assistant with us)..... Use an alligator clip on negative (black wire) side of multimeter and clip it to metal on PSU case grounding it - confirm a perfect ground by checking resistance/ Ohms test between clipped lead and any of the ground wire - (actually if you are having issues you can check all of the ground wires with this test).. Thank you, much appreciated.
thanks for sharing your knowledge and giving me the confidence to debug a faulty PSU to graphics card connection
What is tolerance for purple wire in V on 24pin connector on PSU? I have reading of 4,6V? All others are fine.
Great video! Thanks for making this.
is testing the 12v output of a standard molex connector(ie from its yellow wire) a reliable way to check the actual voltage on the 12v rail of the psu?According to hwinfo64,the voltage on the 12v rail of my psu is 11.88v on idle and 11.59V on load.But upon testing the molex connector's 12v output i found that the idle voltage is around 12.26V and on load it goes upto 12.29V.
So which reading is more accurate?Are measurements taken using software reliable at all?I have a corsair CX 450 power supply btw-does it appear to be working normally or is the voltage on its 12v rail a bit on the lower side?
ALL of the yellow wires (+12v) on a standard PSU come from the exact same source. So yes. you should be abler to read the same voltages from any of them. Same for the Red (+5v) and orange (+3.3v) wires.
HWinfo is not reading raw power from the reading PSO 12v rail. It is simply displaying what some sensor in the MB is reporting.
If you are testing the PSU, then take your readings from the PSU.
When you test the motherboard plug supplier, is it necessary to test all the wires of the same colour in one connector, eg all the red +5V wires. Surely if one red gives a correct reading then all the other reds will give the same as they are supplied by the same rail in the PSU. Likewise for yellow, +12V and orange, +3.3V. Wouldn't testing one yellow and one orange wire be sufficient? Also why is it necessary to test the mains voltage? It's what voltages come out of the connector plug that's important?
Thank you! I know the power supply works now, even got the drives working. Now need to troubleshoot the motherboard and the power switch.
Really straight forward and well done video! Nicely done, Sir.
Thanks for this vid I was able to check my power supply it was ok but still no turning on computer so I started to mess around with it by plugging every thing in then using multimeter on that diode option and plug the multimeter into the green black wires then not just the power supply fan worked but the cpu fan as well then pressed the power button and the computer turned on. So thanks for showing me what I needed to do with the fan cos it helped with actually turning it on
As long as it works, I'm glad for you!
Thats so weird, to me(a noob)..why does this work?
Masha allah bohot acha video very good method to teach us about pwr supply thnx and shukran bhai
Thanks a lot. Very in depth.
Nicely and deeply explained
Keep up the good work 👍
Thanks bro 🙏 🙏 🙏
Fantastic video! Everything is explained beautifully. I've a noob question though: I
Is there an easy way to check the voltages coming directly from the PSU rails by opening up the PSU?
You could always test from the solder points on the bottom of the board. That would be a lot of unnecessary work, unless the wires are missing.
Thanks brother! This was a simple lesson and it helped a lot
Very professional job on explaining this in detail along with safety procedures.
I would assume this can be used to find out the values on a modular power supply's end (with no cables attached)?
Yip same procedure.
Fantastic Video! Thank you
Thanks for the video 🙂!
Good vid but my blue and yellow wires wont read on the 20v setting so i put it on the 200 setting and they read 2.16 and my red and purple are at 8.5v and orange is 5.5v is my power supply stuffed any advice would be appreciated
Thank you brother, awesome video. I am getting all the right voltages but pin 12. No 3.3v! What pin 12 used for?
Thank you for this. Great video
Thank you for this video!
Very helpful- Thank you!
Excellent ...
Excellent that was what I was looking for, like knowing whether the power source worked or not. Thanks
thanks!
useful thanks
Excellent video I learnd how to turn on PS without motherboard. Also very good picture of power plug pinouts and you even added the tolerance ranges for each pin Excellent. May I borrow your assistant hands i need some one to hold things when I am working. also nice touch zooming in on the power cord symbols. I also like that you were talking us through the tests so I new exactly where i was. Subbed and Like cheers
thank you very much! perfect guide!
Thank you sir very well explained
Thanks for good information.
if blue wire reads -11v instead of somewhere 11.52 to 12.48, is it fine?
Super...I understand this video 😘😘😘😘😘😘😘😘😘😘
Hi great video as always. I have a question regarding a JeanTech 400watts power supply. I have done the test shown in this video and the results are much higher than one would expect. Orange is 6.7 volts; nothing on the blue; red 10.6 volts; purple 10.5; 26.2 from yellow!! It is a 20 pin ATX supply. I have googled for a pin out for this particular power supply without success. Should all ATX power supplies be the same? Thanks for any help you can give me.
Idk if you figured it out. But from the sounds of it your PSU was bad. Blue should have shown 12v, but yeah unless you got some weird PSU/mobo combination they should all be the same set up, maybe with different coloring on the wires, but not the order and voltages. Basically it makes it easier for people to buy a PSU or mobo if they only know how many pins they need.
Also the higher voltages could have been caused by a few things, simple reasoning is that your voltmeter leads suffered oxidation and wasn't making great connection or the battery was low.
Harder to verify is that it could be a grounding issue and you're connecting right, but when it reads, you're actually adding up voltages from other pins.
What if the voltages are above the tilerance? So instead of 3.3 I have 3.45? Just one example, all my readings are at thr top tolerance or slightly above it.
Would that cause my pc to power up (fans spinning, lights shining) but system not booting up or sending signal to monitor?
Very informative. Thanks.
Good Day
how to adapt an atx source for pc dll mini.
larger atx connector and the smaller dell all of 24pins
Your video is very helpful.
I just tested a Corsair AX1500i PSU that I found in the TRASH! 🤦🏻♂️ Knowing that to just power the unit up isn’t a good enough test, I got a pinout, watched your video...and found every output voltage to be SPOT ON! This PSU sells for between $480 to over $700! The things people just throw away. 🤦🏻♂️
Found a nice tower with fans and PSU still in it by the dump not long ago. Not worth $300 but money is money. People get stressed and throw away good stuff while moving.
thats what i want to this video,best tutorial, thats why i am subscribe to your channel thanks for sharing
Who is the robber???😂😂😂
🤣
Girl
I might be mistaken but that is probably his wife. Hence the covering. Nonetheless if it is in fact his wife tis quite adorable how she is supporting him both literally and figuratively
I AM DEAD 😂😂😂😂
It's not a robber as you think so, it is a robber of his heart. That is waifu!
Thanks for sharing G
Great video! Helped me fix my computer!
You're welcome!
what was your problem? I just built my first PC and it doesn't boot up. I just tested the PSU and it works fine so I think it may be the motherboard.
Getting -14v on my blue #14 input is this within normal range for a 700w power supply? Pc wont turn on at all other than flash of light on power button. Any ideas?
Did it end up being your psu? My blue shows -12.9v and I'm also confused
Helpful video, thank you!
Hey! Informative video. This is my first pc build. My system turns off after 10 seconds and turns on again in cycles. I tested my Corsair Rmx 850 like this with the ram, GPU and storage in it to get some load on the PSU. The voltage matches perfectly with the diagram but the PSU still turns off after 10 seconds of spinning, yet the lights on the components stays on and I think the HDD stays on. Is it my power supply?
I'd check the CPU for overheating and use something like memtest on the RAM if the PSU appears to be good. With that said this PSU test is not the end all and you can still have a dysfunctional PSU while getting good readings from a multimeter.
Thank you soooo much !
This is a very helpful videos. I just subb for life!!! I tried this steps and follow everything on multimeter. But I always lack 2 volt to all of the pins. Does it means that my power supply is bad and needed to be change?
I need to test my 6 pin & 8 pin GPU cables/output from my 1300 watt power supply. Where did you get that pinout chart? I dont see a link to it above?
Does this color code for power supply cable are compatible for any brand of PSU
One of my readings was -12.82 volts on a 12 V pin which is outside the 4%. Is that a problem ? Excellent, clear video. Thank you very much.
Good video,my problem is faulty pc start/up then pc runs ok.i have been suspecting power supply to be the problem so with the help you have shown i will now test my power supply unit following your advice and chart.thank you.
Any updates?
Thank you!
sorry if i missed it techy stuff is not realy my jam but i am trying to learn. maybe i didn't catch it but did you mention what we should do if the psu works but it restarts abruteply and consistently in weird times? for instance..when you did the testing if even ONE pin come out with a number too high or too low even though would this be a psu replacement?
hi my blue cord comes up as -11.1 so does this mean the power supply is no good and need a new one? or can i fix this? thanks
Whats the brand of your digital tester
Thanks a lot sir!!
this tutorial helped