Using a "Power Supply Tester" to test an ATX computer PSU (and a voltmeter too)

I have been building computers for many years and it seems like I've always got one machine in the house in some state of being "upgraded." I came across this little gadget on Amazon and thought, "hey, that is simpler than using a multimeter."
It came from China and it was here in literally a week. (The last few things I've gotten from China have been sent lightning fast.)
Anyway, so the Power Supply Tester comes with literally no instructions. This turned out to be a good thing. It makes for a good kids project to figure out: (A) how it should work, (B) whether it, in fact, works like we think it should, and (C) whether or not it is accurate.
So, we starting reading up on the ATX Power Supply specification. There is a huge amount of interesting information available regarding how the ATX standard came about, who promotes the standard, and so on.
It turns out that we have a great "demo" power supply that actually has a minor issue (over voltage) that the tester detects. We use the Power Supply Tester to check the "good power" self test result in miliseconds, and test both the 24 pin motherboard connector as well as a 6 pin, twelve volt lead. The results are displayed with voltage details in a liquid crystal display screen. We also use it to check the MOLEX, SATA, and floppy connectors. These peripheral connectors are only tested using red/green lights. We then dig a bit deeper using a multi-meter to test the 3.3 leads and take a look at the VSB (Voltage Stand By) functionality.
We hope you enjoy. We will be making more videos in the future, so please subscribe.
Thank you!

[@michaelperugini4199]

Hope this helps Manual: 1. Plug-in 24pin and plug-in (P4 / P6 or P8) connector into the tester before turn on power. - 20pin ATX PSU: use P4 connector. - 24pin ATX PSU: use P6 connector. - EPS PSU: use P8 connector. 2. Turn on your power supply 3. LCD show each voltage and P.G value on the screen automatic and you can hear 2 beep sounds. 4. ATX power output connector checking one by one. - If power output is working, the LED will light on - If power output failed, the LED will not light on. 5. Plug-in (HDD/Floppy) connector and check LED light. (+12V1/+5V). 6. Plug-in SATA connector and check LED light (+12V1/+5V/+3.3V). 7. Remove the connector after your checking. 8. DO NOT plug-in 2 connectors in to the tester at the same time. ( Only 24pin and (P4/P6/P8) 9. Abnormal voltage detected will not display on the screen. 10. No voltage detect, "LL" will display on the screen. 11. Detected Voltage lower than Min. value, "LL" will display on the screen. 12. Detected voltage higher than Max. value, "HH" will display on the screen. 13. When detected voltage is lower than table value (A), will alarm. 14. When detected voltage is higher than table value (B), will alarm. 15. P.G value detected lower 100ms or higher 900ms, P>G value is abnormal and alarm. When abnormal happened, it will alarm and relative digit blink on the screen.

[@thesummertune]

yes, thanks. mine it's in chinese.

[@williamrkm]

the PSU tester won't work if the 4P of 24P ATX PSU is plug in at 6P

[@Sam-K]

Nice! I've one question; does this tester has support for 6-pin and 8-pin (Including 6+2) VGA connectors? Thanks!

[@mikedahms3600]

I've been using one of these for several years now and wanted to share a link to a 'HOW TO VIDEO" for one of these testers for a friend who has never used one(he lives several states away). Thank you providing a video I am proud to share with him. Job well done. Thank you, Mike

[@sirlonewolf816]

Thanks for the video. As you stated "this Tester comes with no instructions", so your guide was much appreciated.

[@markomus1]

I've had one of these for years now and I LOVE it! I've been in business since 2007 and can't remember exactly when I picked one of these up, but it's seen no shortage of use in years I've had it.

[@scuba60056]

3.3 Rail came on as you started the supply running. Voltage with a multimeter is non-load voltage. This test block is load test voltage.

[@Stackamillie]

Thank you. I know I'm like 10 years late but I'm glad I ran across your page. Learn so much

[@2verb]

I ordered one of these and never having used one was at a loss how to navigate the nearly non-existent instructions. (The package contents say a manual is included. They must mean the sad bit of text on the back of the package.) So this video told me everything I needed to know! Thanks!

[@johnniec2861]

I have been using these for a long time, but never thought to test with the Multimeter duh,, ive probably discarded good powersupplies in doing so,, Very good video on these, and i now know too to not hook sata , molex and floppy all up at the same time as i have always done THANKS this is the most indepth and technical video about this tester !

[@DanielsGameVault]

I use the exact same tester at work. LL stands for "LOW" and it can also flash HH if that particular voltage goes too high ;)

[@sirlonewolf816]

OK, thanks. I was wondering what LL meant.

[@STUDIOJCCAPCSFF]

ooooh thanks

[@videosallnight]

These are available from Amazon (Fuhengli store) for $15.99, and on eBay for prices starting around $11. I have always tested ATX power supplies by grounding the green wire (pin 16) and measuring the voltages with a voltmeter. However, this is not a guarantee the supply is working correctly, as the voltage must be measured under load. I have had computers fail to boot even if the voltages measure up and the supply meets the wattage requirements. If this happens, resistors must be used to provide the loads. Remember that the resistors must be rated for the required power, or you will fry them. This often means having to put several in series or parallel.

[@scuba60056]

LL Means Low Level Voltage condition

[@cyborg6294]

Sir Lord George Edward Reynolds Walinski I got that so should i change my PSU or that is just false positive?

[@CollinMcrae69]

@@cyborg6294 If you plug in it and LL come out, yes you do.

[@Medieva1]

@@CollinMcrae69 Wait so I just tested my PSU and L.L appears. Also my pc doesn’t turn on anymore after months of having issues of sudden crashes. So does this mean my psu is the culprit and I replace it?

[@CollinMcrae69]

@@Medieva1 Maybe yes, just trying another psu for make sure, "LL" mean your psu is fail for sure, psu is vital a little fail can make ur pc ruins

[@frozenelectronics]

Just wanted to point out, if the voltages are a little high with no load, that's usually okay (as long as you're within +/- 10%). If you checked the voltages with a running computer attached I guarantee they'd be spot on (at least for a quality power supply).

[@cyborg6294]

10% or 5% may be more correct

[@jaxman1235]

I bought one of these and it works perfectly because of this video. . Without this video I probably would not have figure it out. Thanks!

[@pyotrleflegin7255]

Useful video. Mine came with no instruction leaflet so this was most welcome. Thank you for sharing your knowledge.

[@yanickpoirier8094]

These devices are nothing less than voltmeters. It does not tells you if the PSU can maintain the voltage levels under load. A failling PSU is usually unable to maintain the voltage level under load causing random reboots. Basically, it is useless for troubleshooting.

[@Junkman2008]

I have always connected everything to tis tester at the same time in order to get my readings with no adverse occurrences. That's how I have always used any tester designed like this one.

[@richardgrandbois1739]

Awesome thanks. Just received tester with no instructions so your video realy helped.

[@X6800]

Finally brought one of these after all these years. Multi tester is fine, but bothersome.

[@Lynthel1000]

I use this specific unit to test client equipment. So far it is great. On this video, you show a cheat sheet of Power Supply specs. I can find the Wikipedia page you refer to, but not this doc. Is this something you could share with us? Thanks in advance.

[@PixelSplash999]

Hi, Good vid. But the tester actually does test the 5v Stand By.

[@nmcarpenter]

Finally, thank you for explaining the PG reading. I had a PSU on the bench that took a voltage spike, all voltages testing okay but PG was at 604m/s. Now I at least have an understanding on what the hell that's trying to tell me.

[@costi08]

Between +12V2 and PG you have 5VSB- Volt Stand By

[@GeneralM13]

small point to consider: the beeping hurts ears! :P

[@jonaszprzybycien6545]

This PSU looks weird. Never saw a transparent one before. Can you tell us whats the model?

[@gula5045]

Very good. Many thanks.

[@MrEp5]

Nice! I got one of these as well but the manual was in chinese.. and or not specific at all. This video explains a lot!

[@micdal22]

Thanks much for your video. I have exactly the same tester. Came with no instructions. Your video helped as I hadn't noticed the connectors at top and bottom. BTW: Have you managed to find a manual or any documentation on this tester?

[@cyborg6294]

Why testing PSU by softwares (programs like speed fan, Aida64, HWMONITOR, and others) give different results with each one?

[@albertjansen5996]

In your video you say it doesn't test the 5v SB (purple) but the display shows clearly 5VSB! and the normal 5v together in the display

[@1776_Reasons]

My P.G. shows 100 but it's blinking/beeping and everything else is in normal range. Does that still mean my PSU is bad?

[@YoutberUser1212]

How can 11.6v power something that needs 12.0v minimum to run properly and still we need to account for efficiency as nothing is 100% efficient where there can be some loss. So if you don't get 12.1v or 12.2v how will this work properly if you get less than the needed 12.0v?

[@rongray1785]

I am using a Coolmax PS tester. All my voltage check out good, however, My PG shows HH. I have tried it on two different PS with the same results. For a quick second it showed 480 on one power supply. My question is what is the PG and what should it read.

[@demontagemontage]

thank you ..how cost??????????????

[@jhoelivan5646]

Hola Amigo Tengo ese testeador igual el pg marca 190 pero palpita hace pitido es normal a que se debe descarte otra fuente normal el Power Good no palpita nada

[@Namtrooper81]

Fantastic video thanks. I own one as well now. THought I'd have a look at other peoples findings.

[@zeus-io3hn]

12 volt is bad undersupply at 11.7v. should it be at 12v?

[@Gary-ts6dh]

Did you lay the load fan flat on the table so it would be more of a load for this test?

[@paulh9761]

Will this thing test 6+2 that you would plug into a video card? I can't figure a way to do that.

[@zaclaplant3001]

I tested my 6+2 pins in the 6 pin slot on a PSU tester and they were normal, but I tested them on the 8 pin slot and the whole PSU tripped... Both of my 6+2 pins do this. I assume that's not normal?

[@ginasrunning]

my tester is flashing L.L and beeping I need to know what to plug into the tester to test this

[@danw3735]

I have one of these also, can you use this device as PSU jumper bridge? i.e paperclip? need to power on a water cooling pump

[@skasuperstar]

Where did you find the manual for the power supply tester?

[@paulkelwaski3271]

Great video thanks for sharing ... informative

[@aksshaysharma96]

any tester works fine?

[@obsey]

What does the "PG" indicator, at the right, with its "ms" (milliseconds?) indicator mean?

[@antoniohernandez6590]

Idk when i bought this but i finally had to use it and didn't know how

[@YinandYangGaming]

i have been having issues with my PC locking up. I will be doing pretty much anything and the screen locks up and I have to do a hard reset. It works perfectly at my friends house but not at mine. I have used two different power supplies but they were pretty low-end ones. Would you recommend getting this device to maybe see what the problem is?

[@thomasdempsey2433]

Thank you for this video. this is exactly what i needed. thanks again and keep up the great work.

[@agentxanon6555]

thank you

[@kerim.s8801]

I plugged the cables to my psu but the "tester" is not going on. Does that mean that my PSU is broken? Because my PC does not work anymore. That's why i bought it and wanted to know if it was the PSU. I have tested my other CPU and Mainboard with the same PSU and it doesn't work. I guess I found out that my PSU is the problem in my case when the "tester" is not going on.

[@ThoseBrothers]

Are you mean't to only test one cable at a time? Or is the correct reading given if all cables are plugged into the tester?

[@JohnSmith-td6dn]

Very nice and informative

[@mjmurawski]

how do I get the pinout sheet that you showed

[@Quadromodo]

They should fit these things on the power supply itself.

[@alexandrec.desouza5511]

Mine is beeping and PG is blinking at 160ms... Any idea?

[@embertilton597]

Mine does that too at 120ms. It did it with a new PSU also which is working fine, but I am still scared that my old psu fried my motherboard and that's what I bought the tester for. If anyone else knows, please reply .... any idea?

[@alexandrecaixinhas223]

@@embertilton597 I had mine replaced, bro. They verified and concluded it was faulty, but I dunno what was wrong exactly. Good luck!

[@kaastrup1971]

do you have a link for that print-out - I see it at wiki but can not print it all on one page

[@sdriza]

I'm sorry, I don't. Let me see what my son can come up with.

[@andressifontes2790]

¿Cuál es el valor de tensión del cable negro ? ¿Cuál es el valor de tensión del cable rojo ? ¿Cuál es el valor de tensión del cable amarillo ? ¿Cuál es el valor de tensión del cable naranja ? ¿Por qué parpadea el valor de +3.6V de pantalla ? ¿Entre qué dos pines del conector ATX24 puede hacer el puente para iniciar la fuente? ¿Por qué pone un ventilador a la fuente cuando la puentea? ¿Qué conectores permite conectar el testeador de fuentes ? Nombra los 5 que hay. ¿Por qué si tiene un LCD con los voltajes tiene también unos LEDs ? ¿Para qué conectores sirven estos LEDs ? ¿Qué significa el tiempo en milisegundos del parámetro PG ?

[@sirbolzenwerfer5069]

What i asked myself and don't understand is, that i get the LL on +12V2. So do i only have to plug in another 6pin connector, to delete this LL? Or do i have to replace the PSU? Because of to less voltage power supply?

[@NikosNisyros]

Hello, when I press the Power button on the PC it starts for half a second and then turns off. I don't know if it is a short-circuit or a motherboard problem. I used this PSU Tester on my friends problematic PSU and what happened was, after I powered on the PSU, the tester gave me a blue screen and a wierd sound and after 2 seconds of *charging sound* it turn off completely. Now, it doesn't show any indications. I hope that the PSU is the problem and I hope that it didn't fried the psu tester. What do you think?

[@NikosNisyros]

You're right. I had it replaced and the computer works like it used to.

[@Anonvee]

@@NikosNisyros its been 2 years but i have the same problem now so im going to test this out too.

[@harounben342]

Did you replace the PSU? @@NikosNisyros

[@arjuna207]

why did you short the green and the ground and not test directly? please explain

[@arjuna207]

+Outlookhazy thx!

[@colmmunnelly8857]

Eli I have just added you to my hero list. its not a big list!

[@user-qz5up4vp7f]

how to give power supply in the fan ?

[@coreybellfaust2154]

Thank you for the video. Most helpful

[@JediNachos]

Thanks for the info! Good video!

[@Sam-fp8zm]

All my voltages are close to normal but the PG number is 0. What does that mean?

[@smilie120]

I've plugged mine in and the PSU fan won't start and I just get LL on all the voltages? Assume my PSU is dead?

[@Dimitris97_GR]

It means that your PSU is not working properly, if it was Warranty still On you should send it back and receive a new one (ik i answer that 9 years later) but someone new might see it and act fast before warranty gone and they have to waste another 200$ on a new psu. So yea the first step is always the FAN working when you turn it on. or doing the ping thingy which i never done it i just got myself that Tool that you plug in the cables and etc.

[@MrTVintro]

I have literally seen this thing with a dozen different brands on it...

[@acoatl751]

Do you think that power supply tester is good enough or should i buy Thermaltake Dr. Power II?

[@juliaurbanski540]

What did you print from wikipedia? I'm teaching this to students and I would like to have that printout for them.

[@solymi]

en.wikipedia.org/wiki/ATX

[@wranglers2]

I can't find anything on that page that would allow me to print out a single page of specs like you show in the video. Can you give me a hint?

[@paulkelwaski3271]

LL usually means low voltage condition

[@siralex64]

my psu tester seems same as urs and mine doesnt turn on after i turn on the psu... could this indicate that the psu is completly dead?

[@thesummertune]

maybe not...it depends what is faulty or burned, if some capacitors or other things.

[@PhoenixPCMods]

Thanks for the info

[@TheBivvz]

Rule of thumb is within 10% is ok right? so 3.6 should be fine, no?

[@cyborg6294]

5%

[@joshtrup633]

cool video. I just got one cuz i just built my first pc and it keeps randomly shutting off on me. I cant figure out why but im doing process of elimination and I tested mine with this tester and everything looks good. So i guess its not my psu. i was wondering if i can plug in my gpu power line into this tester anywhere? cuz im thinking its my gpu that is faulty. windows says fualty hardware in my event veiwer for the crashes. Im also getting blue screen (video_tdr_Failure).

[@harikrishnankm5628]

can they be used as converters

[@TheBlarghzorz]

I just used this an the PG read as zero. Can you shed some insight?

[@GnomishUprising]

+TheBlarghzorz My psu has stopped working pc ,wont turn on PG reading is showing zero on it tried on a spare psu that is working and powering my pc now and that shows PG reading of 280ms so i assume zero reading is showing a fault with in the psu of some kind. nice btw vid OP thanks

[@brandocv]

I get crashes when stressing the PSU/GPU, is there a way to test it under load with this?

[@JonnyMac351]

No it doesn't test under load sadly

[@dularamalindu427]

thank you. that helped me.

[@madmark0]

my pg is 0.0? but it powers things...

[@S10VNoDivo]

Me too. Did you know what's wrong?

[@fowlerprepress8865]

Link to the instruction sheet: kingwin.com/wp-content/uploads/Manuals/POWER%20SUPPLY%20TESTER/KPST-01_user_manual_FINAL_060418.pdf

[@sdriza]

Awesome! Thanks!

[@kennykintung]

hi, where is this cute little device from ? Is it okay to buy it in China? I see something look exactly the same in China market, I don't know if that's the rip off or something

[@sdriza]

Kenny Kenny Sorry for the very late reply! It's fine to get one from china, that's where this one was made.

[@VRUAN]

Kenny Kenny I am sorry to say no. Not that it is a rip off but in China they use 220v, so all electrical devices, for example, an electrical razor, are different from those in USA.The PSU they use there is 220 v, too.Buy it from Amazon.com

[@VRUAN]

Thanks for the comment...I made mine differently because I had a WaterPic oral water floss bought in the US and was brought to China when travel. It brew up and smoked immediately when I plugged it in a 220 power source.

[@RoadRunnerMeep]

That constant beeping is triggering me. I'd end up desoldering the internal speaker just to keep it quiet :(

[@WilliamStAmour-vc1bo]

No 3 volt light on during test = bad?

[@johncv66]

AGPtek Power Supply Tester 12+ L.L mean?

[@louisb.7544]

Low level voltage.

[@xooommm5656]

I’ve also tried updating windows

[@xooommm5656]

I’ve been getting all blue screens lately my pc boots fine into Windows and runs games fine but it just randomly reboots I’ve swapped the hardrive and reinstalled windows and still having the same issue I wonder if it’s bad ram or power supply please get back to me if u can thanks

[@josephherrera4771]

I would make a ram test on a different computer and then check the power supply.

[@alog2]

his tester is hot plug 😂

[@PhuckHue2]

LL means LL Cool J

[@johnharper7880]

They should pay you a royalty.

[@kjotuber2729]

im here for auto multitester..

[@ricardoballantyne1057]

Hi my name is ricardo i would like to get a copy of that readout i have d same tester like yours please send me d link where i can print it out please thank u stay safe be safe out there

[@asepbetta9952]

good , save for study

[@Orange-Jumpsuit-Time]

You won't be able to use it on a Dell power supply. Dell has their own ATX wiring standard, basically forcing you to buy their PS unit.

[@AlistairBrugsch]

Not all Dells. And mostly only older ones. That uses to be true ~15 years ago but more recently they switched to be standards compliant (BUT I wouldn't trust them and would still double check!)

[@HVinduction]

This is useless since it can deliver the voltage but some times not the amperage due to leaking capacitors or poor quality. This is a waste of money. You have to take a look in the PSU and see if there are bad capacitors and take a look at the PCB. Some have very small transformers and they are way overrated.

[@thexxxxxxxxxxxxxxx]

I HAVE 12V IN 12VV1 AND IT SHOW L.L IN 12VV2, I HAVE A TM-350-PSSR-M3, THAT HAVE 12VV2 ? TOO?

[@thexxxxxxxxxxxxxxx]

I ONLY SEE 12V+ IN THE DATASHEET, NOT 12VV1 OR 12VV2

[@greywolf271]

One huge drawback of these pissy little test devices is that the high current draw for modern motherboards is not measured. I pulled apart one of this model and the load resistors are about 5 watts each. If you want to do a proper test of your PSUs, build one yourself.

[@Desmo-13]

ARRIBA ESPAÑA

[@user-mo1bb8wy5v]

Use correct connector 4p !!!!!!!!!!!!

[@Desmo-13]

PERO ESTO QUE ESSSSSSSSSSSSSSSSS

[@shabboz2848]

Or.. Just use a freakin' multimeter.