Psu ripple and hard disk problem - Page 1
Forum section: electronics / repair

author: NOCTURNE
author_rank: Contributor
timestamp: February 19, 2021, 11:02:38 am
content: Hello to allI have a 750 watt PSU for several years (about 5 years). my HDD making noise and freezing just a millisecond I replaced the hard drive and realized the new one has the same problem again.then I realized that the problem is with the power output ripple, and by replacing the input and output capacitors, the problem was solved for 9 months.After that, it happened again and this time bought some very high quality and expensive capacitors and changed all the capacitors. The problem was solved.But now, after 2 months, the hard drive has the same problem again and I do not know why the capacitors break down so quickly again, even though they are much better than before, apparently, they can not clean the output ripple properly.I wanted to know, do you know why it happened so quickly? Is there a problem with the electricity in the house? or because the output filter may have a fault that could damage the capacitor's ripple cleaning? I always used up to a maximum of 400 watts of power wattage, I am really frustrated.

author: PKTKS
author_rank: Super Contributor
timestamp: February 19, 2021, 12:18:01 pm
content: A wild guess...Since some couple years... hardware has gone up to the 500Weasily with these "modern" GPUs now required.The problem is with those absurd power hungry devicesis that such enormous power will be dissipated in componentsas well.. capacitors were never meant to handle such HIGH FREQUENCYat such HIGH POWER RATINGS..Nevertheless they are being used daily and such stress willcertainly make their life shorter. (HEAT MOISTURE BRAND... POWER...)My hope in the near future is that that FORM FACTOR can be changedenough to split such stupid power ratings among different PSUsinstead of overloading a single one with such load...A single 1200W for a PC ? this is a disaster waiting to happen.Try a different brand or DOUBLE YOUR PSU to minimize HEAT...and stress..Paul

author: tunk
author_rank: Super Contributor
timestamp: February 19, 2021, 02:00:35 pm
content: No expert on capacitors, but I'm left with theimpression that not all capacitors are createdequal. The new capacitors, were they low ESR?

author: NOCTURNE
author_rank: Contributor
timestamp: February 19, 2021, 03:22:18 pm
content: Quote from: PKTKS on February 19, 2021, 12:18:01 pmthanks for the replayit's a real 750 PSU, not peak 750 and I don't think its because it is not able to handle 400w since I checked the output voltages at the proper pressure and it was not dropping out of the standard voltage rangealso, caps are new I getting more info in a replay to tunk

author: wraper
author_rank: Unknown
timestamp: February 19, 2021, 03:25:11 pm
content: If capacitors you used for repair were general purpose type, even if super high quality, they will fail very fast.

author: NOCTURNE
author_rank: Contributor
timestamp: February 19, 2021, 03:28:33 pm
content: Quote from: tunk on February 19, 2021, 02:00:35 pmQuote from: wraper on February 19, 2021, 03:25:11 pmthanks for the replaysthese are my output filter capacitors datasheets:https://silmic.ir/wp-content/uploads/2020/05/ME-WX.pdf- 2200 and 25volthttps://silmic.ir/wp-content/uploads/2020/04/al-ky-e-2020.pdf1000 35 voltthey all have high Rated ripple current number in their datasheets----------------------------------------------also, I wanna say the ripple iam talking about is not a ripple happening on output voltages transparently, since they all seem really stable as far as measured them and in standard range even in pressure.but this ripple happens in very high frequency I think and only can see with an oscilloscope maybe?---------------------------------------------------------i wanna know if the caps failed after 2 mounts only or something causing the output filter to not working properly

author: wraper
author_rank: Unknown
timestamp: February 19, 2021, 03:33:19 pm
content: Those capacitors are fine (unless dodgy stuff from ebay or aliexpress). Most likely there was some other problem in PSU.

author: NOCTURNE
author_rank: Contributor
timestamp: February 19, 2021, 03:37:04 pm
content: Quote from: wraper on February 19, 2021, 03:33:19 pmdoggy stuff? fake ones or the ones were on the shelf for a long time before selling? I don't think they are fake and also 2 mounts is a very very short time for such caps to fail

author: wraper
author_rank: Unknown
timestamp: February 19, 2021, 03:57:50 pm
content: Quote from: NOCTURNE on February 19, 2021, 03:37:04 pmEbay and ali are full of counterfeits, much harder to buy genuine rather than fake crap. 2 months is about right for cheap general purpose capacitors to fail.

author: fzabkar
author_rank: Super Contributor
timestamp: February 19, 2021, 07:22:22 pm
content: The +5V supply to the HDD is mostly down-regulated to Vcore and Vio levels for the digital logic. The +12V supply drives the spindle motor and voice coil. The +5V supply is also applied to the read/write amplifier ("preamp") via a filter inductor.

author: NOCTURNE
author_rank: Contributor
timestamp: February 19, 2021, 07:50:11 pm
content: Quote from: fzabkar on February 19, 2021, 07:22:22 pmthanks for the info but i couldn't quite understand what you want to say

author: fzabkar
author_rank: Super Contributor
timestamp: February 19, 2021, 09:51:02 pm
content: Quote from: NOCTURNE on February 19, 2021, 07:50:11 pmI'm just saying that the HDD has a lot of electronics which is designed to filter out noise from the supply. I would be more inclined to blame the HDD rather than the PSU.

author: wraper
author_rank: Unknown
timestamp: February 19, 2021, 10:16:21 pm
content: Quote from: fzabkar on February 19, 2021, 09:51:02 pmFWIW I've read plenty of stories about HDD emitting weird noises and prematurely failing due to bad PSU. As of filtering on 12V, there is barely any. Also ferrite bead won't filter anything except very high frequency noise.

author: NOCTURNE
author_rank: Contributor
timestamp: February 20, 2021, 11:04:30 am
content: Quote from: wraper on February 19, 2021, 10:16:21 pmQuote from: fzabkar on February 19, 2021, 09:51:02 pmI found this on the internet seems somehow related to my problem this article is also indicating bad caps of the output filterPower Supply works, but the game is flakey on it: Check the filter capacitors on the output section of the power supply. Look for ones that have split tops or ones that have tilted over or lifted up because the rubber plug has popped out of the bottom. If they all look OK then either shotgun them or check the outputs with an oscilloscope and look fortrash high-frequency AC ripple on them. Replace the caps as necessary to clean up those outputs, fix any cracked solder joint, reassemble, and test.http://electronics-diy.com/repairing-switching-power-supply.php------------------------------------------------------------------------------------------------------also, I am going to build a portable cap changer with electrolytic caps for output. I tested this before and this worked but somebody in another forum said: this time add some polyester caps for high-frequency ripples on output regarding your current flow this even increases your cap's lifespan.----------------------------------------------btw I know buying a new psu is best option but currently i cant do this since this kind of components are extremely expensive here for our currency.

author: PKTKS
author_rank: Super Contributor
timestamp: February 20, 2021, 01:24:01 pm
content: I have also read some folks stating that these new trendy PSUsin which they value most the badges and that crappy plus gold shit...are indeed failing short to supply proper power on some GPUs in veryspecific cases.. folks which measure the in rush current of some gamesare getting currentSPIKESof short durationin orders of double or triple the actual capacity of the PSUs.Igors LAB already checked these spikes with proper equipo in whichthe time window used (resolution) exceeds even these new NVIDIA PCATrecent MEAS toolsSo in plain facts those PFC based boosters can not provide thesefast current surges ... and these power ratings fall shortly withHIGH RIPPLE or even undercurrent capacity.Boosters diminish the dynamic current capability which ledthese cases to the last hope solution of OVERSIZING PSUs toat least double ratings... in case these fast in rush currentcan drop them down...More and more cases I have read last months..Sad conclusion that these PFC based PSUswith badged efficient ratings are crappy garbagefor serious power hungry high current spikes demands...Paul

author: NOCTURNE
author_rank: Contributor
timestamp: February 20, 2021, 05:31:45 pm
content: Quote from: PKTKS on February 20, 2021, 01:24:01 pmdamn dude nice infoi didn't know there's Npcat equipment out there for real test, although for my case this is not the problem...do you know which brand have better psu for these specific scenarios or i should go for double the wattage every time buy a psu ?thanks

author: wraper
author_rank: Unknown
timestamp: February 20, 2021, 05:43:22 pm
content: Quote from: PKTKS on February 20, 2021, 01:24:01 pmOh my, you again with baseless PFC hate as if it's what's wrong with this world. And cheapest and crappiest PSUs made from shit and sticks, you are advocating for, supposedly should work fine? Would you mind to provide a quote from Igor saying there is something wrong with PFC?

author: wraper
author_rank: Unknown
timestamp: February 20, 2021, 05:51:20 pm
content: https://www.igorslab.de/en/the-battle-of-graphics-card-against-power-supply-power-consumption-and-peak-loads-demystified/5/Quote

author: PKTKS
author_rank: Super Contributor
timestamp: February 21, 2021, 08:21:41 am
content: geez how can i hate a circuit....plain simple facts i am tired to see...BOOSTERS ARE NOT GOOD DYNAMIC CURRENT SOURCES...it took some time to someone with the right tools and skills to spot that..check the current probe setup used and how to see that spotted.. IgorsLab videos provides quality tests

author: PKTKS
author_rank: Super Contributor
timestamp: February 21, 2021, 08:49:37 am
content: ... my next question is ..how can someone without that awesome setup.. decides which PSU can or can not cope that current surges..i have seen a lot of these modern stuff failing.. or just shuting down..when not deadly crapped by some intense surge during a game session

author: PKTKS
author_rank: Super Contributor
timestamp: February 21, 2021, 11:23:37 am
content: Having 4 R&S scopes with those current sensing probesattached is probably not affordable for folks just wantingto evaluate if some budget PSU will actually "works" withsome gaming card...Actually it seems cheaper to oversize the PSU itself..Just an amazing quality MEAS setup...https://www.igorslab.de/en/power-recording-graphics-card-power-supply-interaction-measurement/3/Wish one of those R&S with the probe ...Paul

author: PKTKS
author_rank: Super Contributor
timestamp: February 21, 2021, 11:36:52 am
content: He actually used a specific HAMEG setup (as I understand..)with proper carefully intervals to spot some tricky "design"limitations of today "modern" stuff.Reading the whole thing with care one thing actuallyspots my eyes even much more than just the BAD PFC design..Regarding GPUs (which are not like CPUs) the typical 431 FB network(which mostly also uses a Type3 compensator) is just as limitedto answer these fast in rush currents and compensate the regulationfast enough..very interesting thoughts on how regulation can put a bad delaywhich will certainly impact other devices which are - as of today -attached to the same POWER RAIL... CPUS disks...IMHO GPUs require a separate PSU.. wo PFCs and even the TL431 seemstotally obsolete to answer that fast in rush..Very interesting readings..https://www.igorslab.de/en/power-recording-graphics-card-power-supply-interaction-measurement/PaulPS.. please note carefully his comments on these.."Over the last few months, I have been able to measure different manufacturer solutions in the supply of graphics cards. Initially, it was smaller cards such as different models of the GeForce GTX 750 Ti, whose power consumption did not really exceed the 60 watts on average, but depending on the model and the clock can generate very high power peaks. Then the 75-watt limit for fractions of a second falls quite clearly, as the graphic clearly shows us:"

author: PKTKS
author_rank: Super Contributor
timestamp: February 21, 2021, 12:13:07 pm
content: ... now 2 more very interesting pages ...specific to CAPACITOR issuehttps://www.igorslab.de/en/power-recording-graphics-card-power-supply-interaction-measurement/8/and the previous pages comparing SINGLE RAIL x MULTI RAIL designs..the ripple spawned across the MOBO... and the HEAT expansion..interesting pages.. how these sum up to shut down the systemor even dead short something...And how bad these "modern" digital control designs can actually bemore a problem than a solution...Again.. this reading is very needed to think problems like thisone on the original post OP.Paul

author: exe
author_rank: Unknown
timestamp: February 21, 2021, 12:13:39 pm
content: Quote from: NOCTURNE on February 19, 2021, 11:02:38 amDid you use an oscilloscope to confirm this?

author: NOCTURNE
author_rank: Contributor
timestamp: February 21, 2021, 03:29:31 pm
content: Quote from: PKTKS on February 21, 2021, 12:13:07 pmIt an interesting article so still I don't know what cap characteristics in the datasheet going to be more important when it comes to my problemI found some of the previous caps datasheet, not all of them but 2200 uf for output there is 1000 uf as well i don't know what was their namehttp://www.elna.co.jp/en/capacitor/alumi/catalog/pdf/rj4_e.pdfQuote from: exe on February 21, 2021, 12:13:39 pmsadly I don't have one but I know at least changing output filter caps will solve the issue for a while.

author: PKTKS
author_rank: Super Contributor
timestamp: February 21, 2021, 04:54:40 pm
content: Quote from: NOCTURNE on February 21, 2021, 03:29:31 pmProbably one of best ever written test relating such kind of issuesin recent boards... and PSUs.He gave us a very useful tip"The question is not so easy to answer because details matter.A suitably selected secondary elco of a Taiwanese or Chinese manufacturer may be quite equivalent or even better if the power supply manufacturer uses a correspondingly high quality class which also excludes greater manufacturing tolerances, than a simpler Nippon product, which has poorer technical specifications but is supposed to score points over the name of the manufacturer in return."After that I never ever consider that "just being brandX or CountryY" enough.There are pretty much a price issue and he even includes Teapo which Ijust abominate .. a selectable one..Another comment that absolute changed my way of seeing things is.."Power supply and graphics card should match. It is not the pure wattage of the total power that is decisive for success, but factors such as single or multi-rail and the available and really achievable currents, which can be delivered constantly even under very short, violent load spikes, without the voltage values buckling at short notice. The question answers the power supply at the end."Indeed these very common Programmable Electronic Load Bench testin which a PSU is classified as being "acceptable" by just being capableof "statically" operating close to the BOX LABEL.. (aka that 600W gold shitso we WILL OPERATE THAT SHIT AT 600W statically... EXPLODED? no. good.)His arguments put that in the potty ..The current spikes ripple just double the problems and withoutthat in consideration...chances are some shit will happen..supervisors will not properly trip the protectionsor devices will just fail when a flood of violent spikes hit the power rails...Definitively modern GPUs need a separate PSU isolated from therest of the system..Old folks will remember that... in 199x.. 3DFX Voodoo cards startedwith external PSUs.. but things evolved chaotic and the pointnow is how to deal with that..Read his comments on OVERSIZING PSU to handle that as well...so the board won't trip PS_ON signal or some protection ina weird way..very interesting.Paul

author: wraper
author_rank: Unknown
timestamp: February 21, 2021, 07:14:15 pm
content: Turning thread about PSU/HDD problem into off topic PFC/GPU bullshitQuote from: PKTKS on February 20, 2021, 01:24:01 pmDoes not pass bullshit check. How more stable input voltage of SMPS somehow reduces "dynamic current capability"? If anything, with PFC input voltage sags less under load spike compared to simple smoothing capacitor after rectifier. If some PSU shuts down due to short load spike, it's because of too sensitive OCP circuit on it's output, nothing to do with PFC. Also GPU manufacturers oversize recommended PSU power rating in a large part due to presence of shitty PSU on the market (which you excitedly promote).QuoteCapacitor brand gives confidence in longevity. Some caps bulge while simply staying on the shelf for a few years. Sure, cheap caps may last as long as top brand, but it's a hit and miss. Also my observation is that manufacturers don't use more of cheap caps instead of less of expensive caps. They use lower amount of cheap caps in cheaper models. They save both on their amount and cost per unit.

author: MathWizard
author_rank: Super Contributor
timestamp: February 22, 2021, 03:25:27 am
content: Quote from: PKTKS on February 21, 2021, 08:49:37 amI haven't bought a PSU in a few years, but I used to read computer PSU reviews by JonnyGuru, he did good in depth reviews of PSU with all the load testing and hotboxes, etc.It seems he's retired lately tho, I can't even seem to access the sites ATM.IDK tho there's some PSU's that on paper look fine, but just can't handle what the more expensive brands can do, that's for sure.I've repaired a few computer PSU's, but a few of them, are so old, I'd what to re-cap the whole thing, if I was going to sell it, and then I'd only sell it for a few dollars anyways, so, IDK what to do with them yet.

author: Monkeh
author_rank: Super Contributor
timestamp: February 22, 2021, 06:21:02 am
content: Quote from: wraper on February 21, 2021, 07:14:15 pmAnd to cover their arses for drawing brutal transients. Why design a better GPU when you can tell the customer to go spend more on something else?

author: PKTKS
author_rank: Super Contributor
timestamp: February 22, 2021, 09:24:07 am
content: Quote from: wraper on February 21, 2021, 07:14:15 pmgeezzzz give me a break...he expalins how to properly oversize your demands..and just remeber academia.. boosts rely on energy storage so elevating volts diminish currenthe notes very well .. what shit happens when a wave of current surge hits a depleted booster.. shit on the fan...simply a bad designregulating LINE instead of LOADat 8x the costPaul

author: exe
author_rank: Unknown
timestamp: February 22, 2021, 09:58:39 am
content: Quote from: NOCTURNE on February 21, 2021, 03:29:31 pmI suggest get one, even a simple one. Chances are you are solving a wrong problem. I understand that replacing caps "helped", but it can be hiding a bigger problem. Like, poor regulation, for example, or excessive noise. Adding fresh caps might make system marginally stable.In other words, make decisions on data, not on guesswork

author: PKTKS
author_rank: Super Contributor
timestamp: February 22, 2021, 12:10:33 pm
content: Quote from: MathWizard on February 22, 2021, 03:25:27 amI tracked this folk a while some.... half dozen years ago...and yes he did some nice posts...AFAIK he went to CORSAIR back then...But.. all of the tests and reviews.. ALL 99.99% of them..are that "STATIC" Electronic Load stress test..Mostly they seem more concerned with that badgesrelated to efficient LINE REGULATION... than actuallynew methods and topology in LOAD regulation..None of them explains WHY THESE SHITTY TRENDY PSUs faillike that of the OP with strange symptoms or sudden tripped off...The very first folk (actually the only one) I have read with proper conclusionsis actually Igor with that solid rock data acquisitionin which PROPER RESOLUTION shows how DYNAMIC CURRENTpromotes such strange results.. and strange failures..And I have seen enough to suspect that a bad design is obviousIt serves absolute nothing a 90% efficient (line efficient) PSUthat can not sustain such WAVE OF VIOLENT CURRENT SPIKES..The OP have good reasons to suspect the CAPS.A very simple way is by REMOVING THE GPU and try usingmay be a very low end video card (or IGPU MOBO)..If the RIPPLE has gone... BINGO.the GPU is causing current spikes beyond the rated capacity.The data gathered by Igor on that is amazing clever..Not a cheap or simple static setup but the very first one to properly gather theDYNAMIC data with PROPER RESOLUTION .. which these new NVIDIA PCATcan not capture as well...These spikes require a new method of LOAD REGULATION for such GPUs.None of these STATIC LOAD TEST will EVER detect that...and failPaul

author: wraper
author_rank: Unknown
timestamp: February 22, 2021, 02:21:24 pm
content: Quote from: PKTKS on February 22, 2021, 09:24:07 amSome knowledge with no understanding whatsoever. A little bit higher voltage does not mean there is less energy. In the same way you can say there is low current in 230V mains voltage compared to 12V, therefore 230V sucks.QuoteWho notes and where notes? Did not see anything like that from Igor. What depleted booster? You are pulling nonsense out of your bum.QuoteWhat is this about? Where is it regulatedINSTEAD? Voltage is both regulated at input by PFC and then at output as well. And since there is way way less mains (100/120Hz) ripple at the input, output voltage is more stable as well. SMPS which outputs low voltages is the same as SMPS that is used without PFC (actually way higher quality compared to crap you promote), PFC is an addition. Bottom of the barrel crap you so eagerly promote, is not even legal to sell here. I should go through your old posts and find a picture of PSU that you posted and said it was good, so people can laugh in this thread as well.

author: PKTKS
author_rank: Super Contributor
timestamp: February 22, 2021, 02:33:00 pm
content: Quote from: wraper on February 22, 2021, 02:21:24 pmOK dear... your point is making people laugh at me...My point is helping the OP wit 2 cents of well pointed information.Hope he can extract necessary bits to solve his case.I had such issues myself and solved them exactly with these tidbits.If your point is mocking me... good luck.Paul

author: wraper
author_rank: Unknown
timestamp: February 22, 2021, 02:33:51 pm
content: Here you go, click the link to see full post and more picturesQuote from: PKTKS on March 20, 2020, 03:47:23 pmAnd completely reasonable comment from other memberQuote from: senso on March 20, 2020, 04:42:03 pm

author: wraper
author_rank: Unknown
timestamp: February 22, 2021, 02:39:33 pm
content: Quote from: PKTKS on February 22, 2021, 02:33:00 pmMy point is you berate good quality power supplies for superficial reasons and promote trash as if it's a salvation.QuoteYour "information" is mostly false and misguided.

author: PKTKS
author_rank: Super Contributor
timestamp: February 22, 2021, 02:44:52 pm
content: For your information I use several of these so called "TRASH"when powering bad garbage video boards on the bench..actually I use them daily combined as i need them....none presented such problems. They are usable in proper range just fine.Each can provide about 350W on HALF BRIDGE configurationthey sustain whatever bad ripple you throw them.. not even warm.and they cost me 1/8 the price..I have others.. in the above 600W range that caused me much more problems instead..weird problems of ripple and sudden shut off..just don't make this thread a juvenile mocking circus..I tried to point the best info availablehard to understand your pleasure in mocking...Even with good pointed information ...Paul

author: wraper
author_rank: Unknown
timestamp: February 22, 2021, 02:58:17 pm
content: Quote from: PKTKS on February 22, 2021, 02:44:52 pmIf they cost 1/8 of the price compared to somewhat decent stuff, they would cost about $3-4 where I live (they don't). Also suggesting that adding PFC increases the price 8 times is completely ridiculous. It adds like 20% or maybe even less.

author: PKTKS
author_rank: Super Contributor
timestamp: February 22, 2021, 02:59:33 pm
content: Quote from: wraper on February 22, 2021, 02:52:21 pmWell with a small adapter very common in crypto mining setups..after the repairs i first try the board with a separate supply..cheaper easy (far easy) to fix and more proper to the job...Available in crypto mining sites... this handy key to such setup..obviously I am not the only one combining ATX PSUs to avoidthese problems...https://www.aliexpress.com/item/32834557384.htmlA bunch of proper cables and protections using ANDERSON connectors..and BINGO.. I don't worry to power garbage video...Usually they were trashed by very expensive PSUs which failed.... the very same ones the OP is having the same problems..which you think I am somewhat fabricatingand god go figure why I would do thatPaul

author: Monkeh
author_rank: Super Contributor
timestamp: February 22, 2021, 03:03:52 pm
content: Quote from: PKTKS on February 22, 2021, 02:59:33 pmThat's because they use large numbers of GPUs and need more power for it, not because you can't power a modern GPU with a proper power supply.Nobody out there with a normal system needs a separate PSU to run their GPU.Quote from: PKTKS on February 22, 2021, 02:59:33 pmAll we know about the OP right now is that he's having problems with an unspecified power supply which he's repaired himself. And who knows if the parts are genuine or not.

author: wraper
author_rank: Unknown
timestamp: February 22, 2021, 03:05:46 pm
content: Quote from: PKTKS on February 22, 2021, 02:59:33 pmOMG, they are the worst thing for crypto due to their low efficiency. You likely to lose on electricity more than saved on such PSU in just a month or two. Especially if electricity in the area costs more than almost nothing. Electricity is a very large part of expenses when mining crypto. It often makes the difference between turning profit or loss.

author: PKTKS
author_rank: Super Contributor
timestamp: February 22, 2021, 03:12:39 pm
content: Quote from: Monkeh on February 22, 2021, 03:03:52 pmTRUE. And i never ever would recommend that to a so called "NORMAL" folk..Which is not doing repair (like this one) to use such methods..Gamers usually want a single BEASTIAL supply with 2 dozen LEDs everywhere..Never ever I would say to combine ATX and use Cc/CV methods in a bench riser...I am not nuts.. I am just pointing a SAFE SUSTAINABLE METHOD OF REPAIR...for whoever can and know how to use themTrashing a $500 buck PSU is one thing..a $16 buck perfectly usable is another thing..Don't put wrong words in my speech.The OP is seeking help and advice..well I have pointed some clever ones..REMOVE the suspected excessive power GPU..Try to fix the ripple...and try to power bad boards with reasonable predictable bench stuff..2 cents of very plausible tidbitsfor a bench repairman.. not for a gaming session...Paul

author: wraper
author_rank: Unknown
timestamp: February 22, 2021, 03:20:46 pm
content: Quote from: PKTKS on February 22, 2021, 03:12:39 pmWell, well, where was a single world about $500? Those are extremely rare outliers. You were trashing all PSUs containing PFC altogether.

author: PKTKS
author_rank: Super Contributor
timestamp: February 22, 2021, 03:30:00 pm
content: Quote from: wraper on February 22, 2021, 03:20:46 pmNo my dear .. let's put this clear for good...I have dealt with PFC countless times...Mostly in CRT monitors like SAMSUNG SyncMaster in the 90s/00sand several types of tubes...PFC are good with well behaved loads in which no current surgesare expected and any LINE fluctuation is absorbed by the front end.Entering this new era of above 500W PSUs in which some insanearguments combined two types of complete different loads...- THE CPU / DISK / USB loads..- THE GPU(S) load itself..into the same ATX case ... (for reasons I can't speculate..)What I can speculate and also provide support information isthat this 2 different loads are not working very well togetherinto the same power rail..The CPU RAIL can work just fine with a PFC front end becauseit does not cause such violent current surges..The GPU RAIL instead is frequently causing strange problemswhich mostly can be spotted by such bad oriented combined design.IMHO GPUS today are urgently in need of their OWN PSU.Which judging by the info above.. requires a new set of criteriaon regulation due to these absurd fast surges...PFCs will fail miserably to answer that kind of surge...they are just not the proper method for that..hope I can make your mocking more clear now.Paul

author: madires
author_rank: Super Contributor
timestamp: February 22, 2021, 03:33:09 pm
content: Just a reminder: 1 Watt = 2 to 3 Chinese Watts(when you buy too cheap to be true stuff)

author: wraper
author_rank: Unknown
timestamp: February 22, 2021, 03:40:32 pm
content: Quote from: PKTKS on February 22, 2021, 03:30:00 pmShow a single oscilloscope measurement of voltage boosted by PFC sagging under the load before claiming this nonsense.

author: PKTKS
author_rank: Super Contributor
timestamp: February 22, 2021, 03:51:48 pm
content: Quote from: wraper on February 22, 2021, 03:40:32 pmgosh you are a persistent bone head...I wish I had such equipo as Igors LAB to do so... I don'tnot even the time or will to "prove you" such simple thing.As soon as a strong enough wave of current surges deplete thePFC bulk capacitor - no matter what frequency the supervisor runs. - thedepleted energy will force the mains switching element to conduct"FULL TIME" (full cycle)..As we all know .. all supervisors are protected to NOT DO THATand enter a protection cycle in which some method will power downthe output.. or not..latter case the switching transistor usually burns bad deadly..Very common fault on modern LCD LED TVs.very very commonPaulPS Alas the way such fault happens is very typical..a frequent state of ALL LEDS ON.. ALL LEDS OFF..which suddenly happens to occur when the energy stored is low..the second cycle just drop the PFC switching element dead...

author: wraper
author_rank: Unknown
timestamp: February 22, 2021, 04:09:29 pm
content: Quote from: PKTKS on February 22, 2021, 03:51:48 pmWhat equipment? All you need is oscilloscope measuring boosted voltage with trigger set to register voltage dips and PC running a game. If there is no such measurement from Igor, and I did not see any, there is no basis to your claims about PFC whatsoever.QuoteBS, you have no idea how boost converter works to make this claim.

author: PKTKS
author_rank: Super Contributor
timestamp: February 22, 2021, 04:19:53 pm
content: Quote from: wraper on February 22, 2021, 04:09:29 pmPFC supervisors usually combine the booster driver and the flyback driverinto a single IC.Such ICs are provided with some protections like OLP/OCP/UVPamong some external level detectors.All PFC supervisors will enter protection cycle as soon as theenergy of the bulk booster is depleted..Such state is determined by opto coupler trigger ramp voltageusually that level is superimposed on the SOURCE of the flybackswitcherSimple facts for any experienced repairmanThat RAMP trigger level is WRITTEN in the IC PIN schemausually that PIN is named CS/FBmeaning Current sensing + Feedback loopPaul

author: PKTKS
author_rank: Super Contributor
timestamp: February 22, 2021, 04:25:39 pm
content: for a layman ...Current sensing will tell the IC that the OUTPUT IS WAY OVERLOADED...and sum a value to FBFeedback loop is the average operating point of the IC in whichit will safely absorb more or less current (regulation)When CS exceeds the trigger limit the transistor conducts FULL TIMEand OLP is tripped. ICs shutdowns the flyback driver ..(of course because the bulk capacitor is dead depleted )

author: wraper
author_rank: Unknown
timestamp: February 22, 2021, 04:40:34 pm
content: For layman I'll explain. If boost converter pass element becomes constantly open, it will explode. And boost converter controllers thus have duty cycle limit. You said it will conduct "FULL TIME".QuotePC PSU don't use flyback topology.QuoteExcept it will not be depleted. Output OCP will shut down PSU way before there is such high load that PFC cannot cope with. Nor PFC exists in a vacuum. It is sized accordingly to SMPS that comes after it.QuoteExcept voltage cannot drop below rectified mains voltage in principle.

author: PKTKS
author_rank: Super Contributor
timestamp: February 22, 2021, 04:47:52 pm
content: In your world ... every repairman on earth is no longer necessary.These modern PFC of yours just will not fail and are perfect creatures...In my day by day I have a box of faulty boards with burnedswitchers and burned transformers as well...If a particular PSU is using a combined PFC IC or particular topologyis hard to judge... as there are way too much ...But as for my experience 99.99% of them are using combinedsupervisors no matter what for cost reasons..The faults are very much the same..under cycled operation leading the supervisor nuts and not trippingthe protections in due time..trivial day by day of repairman..Paul

author: wraper
author_rank: Unknown
timestamp: February 22, 2021, 04:55:02 pm
content: Quote from: PKTKS on February 22, 2021, 04:47:52 pmIn your strawman world, I repair stuff myself. If you are not qualified to repair PSU with PFC and find it hard, it's your problem. In high end PSUs, complexity of PFC is one of the smallest hurdles in repair, as it's one of the simplest things there.QuoteThey are not perfect. Nor they are some inherent flaw.QuoteIt's only your assumption. Output OCP of modern PSU works pretty well.

author: PKTKS
author_rank: Super Contributor
timestamp: February 22, 2021, 04:59:16 pm
content: Quote from: wraper on February 22, 2021, 04:55:02 pmyeap I had no such luck.. pretty much a much higherfailure rate than expected with several "expensive" brands.If you haven't .. good ... for you.Keep the good luck!Paul

author: wraper
author_rank: Unknown
timestamp: February 22, 2021, 05:05:57 pm
content: Quote from: PKTKS on February 22, 2021, 04:59:16 pmDunno what failures there were. But blaming OCP is dumb. Overload means there were other problems in system other than PSU. If there is no problem, OCP does not kick in. And if it ever kicks in,PSU shuts down immediately. Also as you like to deal with cheap trash, probably those power supplies were trash as well.

author: bdunham7
author_rank: Super Contributor
timestamp: February 22, 2021, 05:23:21 pm
content: Quote from: PKTKS on February 21, 2021, 08:21:41 amCompared to what and over what timescale?The PFC booster maintains the primary-side reservoir cap at a certain voltage. If the PFC were causing whatever problems you blame them for, there would be a drop in the voltage at that stage. Is there? And you think the PFC is slower to respond than waiting for the next power cycle? And any current 'spikes' shorter than the switching cycle of the PSU have to be handled by the output caps anyway, the circuit can't 'respond' any faster than it switches.

author: bdunham7
author_rank: Super Contributor
timestamp: February 22, 2021, 05:33:57 pm
content: Quote from: NOCTURNE on February 19, 2021, 03:28:33 pmCan you tell us exactly where you purchased these?QuoteOther than an oscilloscope, how else would you determine the output ripple on such a PSU??

author: PKTKS
author_rank: Super Contributor
timestamp: February 22, 2021, 06:18:38 pm
content: Quote from: bdunham7 on February 22, 2021, 05:23:21 pmWell here we go again..I'm not BLAMING PFC.. this RANT comes from these folks whichinsist mocking me because I have said that several PFC based ATXpresent such strange failures...until Igors LAB conclusions with proper data gathering and excellent commentsall my failed ATX with PFC front ends present some overload typical symptomFor the record .. if anyone still thinks that PFC is NOT A FLYBACK TOPOLOGYattached is a fairly typical ATX PFC IC supervisor...with integrated booster driver anddoublesingle switch flyback forward...90% of the PFC ATX I have are CM68xxx based...Surges in the depleted booster are likely the problem...where the flyback OLP failed to shutdown the driver in due timemeasure these surges is pretty much a very hard taskas pointed in Igors LAB excellent articlePaul

author: wraper
author_rank: Unknown
timestamp: February 22, 2021, 06:42:02 pm
content: Quote from: PKTKS on February 22, 2021, 06:18:38 pmYou made multiple super long posts filled with nonsense and derailed the thread.QuoteCM6800 based PC PSU useforwardtopology.http://www.bannerspan.com.tw/technical/Champion%20Micro/CM6800%20Design%20Guide.pdfWhat "flyback forward" should even mean, it's either flyback or forward.QuoteIgor made measurements that GPUs have very short current spikes in consumption. Your conclusion - PFC is bad and cause of all evil.QuotePulled out of ass with zero measurements done. Is your claim those faulty PSU were undersized for the system or what? Otherwise overcurrent protection shall never trigger.

author: PKTKS
author_rank: Super Contributor
timestamp: February 22, 2021, 06:46:37 pm
content: my dear dear colleague ... spare me your mocking andpersistent rant about my person..5 minutes ago you have said that PFC ARE NOT FLYBACK..I am sorry to disappoint you so many times...but most PFC CIRCUITS ARE INDEED COMBINED WITH FLYBACKsmost of the time to adequate voltages and ISOLATE mains...and... the DIRECT, the FORWARD (single and double switch) variantsARE INDEED FLYBACK topologies as well...i did not made such classification.. this is academia.spare me your persistent will to insult me ..this is sickPaul

author: wraper
author_rank: Unknown
timestamp: February 22, 2021, 06:54:01 pm
content: Quote from: PKTKS on February 22, 2021, 06:46:37 pmForward is not flyback. It works very differently. Even if schematic may look somewhat similar on the first glance.QuoteAcademia failed you. It teached you some things but you failed to understand.https://www.we-online.com/web/en/electronic_components/news_pbs/blog_pbcm/blog_detail-worldofelectronics_45887.php#:~:text=Forward,a%20transformer%20isolated%20buck%20converter.&text=The%20forward%20converter%20does%20have,is%20in%20excess%20of%2015A.Quote

author: PKTKS
author_rank: Super Contributor
timestamp: February 22, 2021, 07:03:32 pm
content: I understand your academic confusion on the issues...I have been there some 30/40 y ago..But several other books and authors will teach you that"FLYBACK" is any topology in which the SECONDARYis ISOLATED from the PRIMARY using a transformer...The key word is ISOLATION.. and UNFORTUNATELY...THERE IS ONE TOPOLOGY ITSELF NAMED "flyback"which is also named "simple switch" to distinguishthat from others..Namely:- flyback (simple switch) or sometimes "offline"- Direct or forward- push-pull- half-bridge- full-bridge- Double switched or double forward flyback..- RCC or ringing choke flybacks..and others more exotic can be found..hope it calms down your confusion...let's stick to the topic where the FAULTS matters most...and how to solve them ...Paul

author: wraper
author_rank: Unknown
timestamp: February 22, 2021, 07:10:42 pm
content: Quote from: PKTKS on February 22, 2021, 07:03:32 pmLOL, I guess what teachers told you turned into a mush over the years. Link please to confirm your words.

author: PKTKS
author_rank: Super Contributor
timestamp: February 22, 2021, 07:17:05 pm
content: Quote from: wraper on February 22, 2021, 07:10:42 pmI would be glad to put links ....But such information comes from books papers andseveral stuff gathered across years...You will be happy to add to the tips that apart the ISOLATIONthe FLYBACKs also are classified by quadrant..they can be SYMETRIC or ASSYMETRIC depending on howthe energy is managed by the core.variants of the above classic ones can also be found...some found their niche in the industry ... some don't..Internet links is something for juveniles.. post 90s..I am older than that.. my book pile is considerable.Paul

author: wraper
author_rank: Unknown
timestamp: February 22, 2021, 07:24:52 pm
content: Quote from: PKTKS on February 22, 2021, 07:17:05 pmIn other words you told BS which you are reluctant to admit. Post a scan/photo from your precious books then.

author: PKTKS
author_rank: Super Contributor
timestamp: February 22, 2021, 07:27:52 pm
content: Quote from: wraper on February 22, 2021, 07:24:52 pmNO.This post is not about flyback lessons...And I am no longer willing to satisfy you clear intention on mocking me.In respect to others and OP I am done with your follyIf not satisfied .. use google.Paulcheers for your circus

author: wraper
author_rank: Unknown
timestamp: February 22, 2021, 07:33:57 pm
content: Quote from: PKTKS on February 22, 2021, 07:27:52 pmYou turned this thread into off-topic circus to begin with. I'm here only to debunk some BS which I can't stand. So instead of proving yourself, and thus embarrassing me, you decided to remain a clown... yeah, right.

author: bdunham7
author_rank: Super Contributor
timestamp: February 22, 2021, 07:40:28 pm
content: Quote from: PKTKS on February 22, 2021, 06:18:38 pmI simply asked you to explain your statement about boosters being poor dynamic current sources.What symptoms are you talking about? What measurements back up your theory?I'm not getting into a semantic debate. If you think two-transistor forward and flyback are the same thing, fine. By your definition I suppose a linear PSU with a stepdown transformer is 'flyback'. Defining the type of PSU does nothing to answer my questions nor solve the OP's issue.What evidence do you have of 'depleted boosters' and how is that related to microsecond current pulses?I had a glance at Igor's website and the links that have been posted here and TBH, I really can't see anything supporting your conclusions.

author: NOCTURNE
author_rank: Contributor
timestamp: February 22, 2021, 11:28:27 pm
content: Quote from: bdunham7 on February 22, 2021, 05:33:57 pm

author: PKTKS
author_rank: Super Contributor
timestamp: February 23, 2021, 11:05:12 am
content: Answers to proper formulated questions....About "flyback" classifications and academic jambo, enough to say that I have over 10.000 schemas of "flybacks" in which most newbies will have a hard time even to understand how to see and classify the topology. Every single CRT over the 70/80/90 own a different and sometime very challenging "flyback"Figures from my bench library from 70/80 are suffice .. there is no FOO-BAR supervisor (as that came over late 80s and several ones are TUBE based SMPS.THEY ARE ALL FLYBACKS. The theory and academic jambo are issue of another topic...Enough to see how messy is such "academia" foo-bar shit...In respect to the simple fact that boosters are very poor current sources...I think a proper example I have been dealing with lately in "modern" PFC LED "TVs"is as the following..- Assume you have a typical "flyback" PFC SMPS- Topology is rather typical a booster front end and a forward converter flyback- Note that most part of the energy is consumed by the HIGH VOLTAGE WINDING on the secondary usually over 100V which powers several LED strips.. medium current but enough energy to be the principal energy part.- Assume we have a FULL ON flickering demand where the BOOSTER is trying to fill the BULK capacitor which is being rapidly depleted by the longest possible cycle allowed of PWM.- Assume a GLITCH happens on the MAINS. Several periods (60Hz) will be empty (no energy)What happens?Very soon the booster is unable to recharge the BULK capacitorThe switching transistor already in maximum PWM timing will consume very fast what is left of energy on the BULK and the opto coupler will raise the even more the timing (OLP) will try to stop the PWM...But... while the the supervisor is trying desperately to refill the BULK an unfortunate race condition may delay the shutdown one or two cycles in which that last cycle of maximum load just burns dead shorted the switching element ..That fault happens mostly because the booster competes with the PWM driver to sustain energy not available .. once the booster is actually a poorly limited by P=V*Id - and having a very high V.. available surge Id is very very short ....Any booster is actually a poor current source under any glitch soon the bulk is dried out..Common fault on modern LED panels..and as it may be the case - it can repeat in other devices ...No I don't have waveforms or such nice data. Reason I have posted themfrom the single source I account for...Hope it settles some annoying tidbits..attached imgs are reduced due to limits of uploads..but they are very high quality - already posted here somewhere...FYI - THEY ARE ALL TECHNICALLY VERY WELL DEFINED "FLYBACKS"lost the count on how many... over 10.000 different very special ones...TO BE NICE TO SOME NEWBIES THE "FLYBACK" AREAS ARE MARKED RED..Paul

author: madires
author_rank: Super Contributor
timestamp: February 23, 2021, 11:35:36 am
content: IIRC, the flyback topology is only used for SMPSUs up to 150W. So you won't find flybacks in ATX PSUs. Just saying.

author: PKTKS
author_rank: Super Contributor
timestamp: February 23, 2021, 12:12:16 pm
content: Absolute CLASSIC AT/ATX up to 500W power design.HALF-BRIDGE FLYBACK TOPOLOGY with TL431 transconductanceerror amplifier limited BW on TYPE3 compensation.Prior the specs on ACPI very common found with 339 delay signalVery important note that half bridges typically have thesplit-cap virtual ground input and a very clean secondarypowerful waveformeasily found on the netPaul

author: MK14
author_rank: Super Contributor
timestamp: February 23, 2021, 12:15:24 pm
content: Quote from: NOCTURNE on February 22, 2021, 11:28:27 pmCapacitors being fake/clones/used, is quite a common problem. Since the proper quality make capacitors, cost quite a lot, from proper suppliers (such as Digikey/Mouser/etc). You have to wonder, where they are able to get all those supposedly 100% genuine non-fake, high quality capacitors from, and yet (presumably), sell them rather cheaply, to you.So (by default), I suspect they could really be Chinese sourced capacitors, being sold/claimed as being 100% the genuine stuff.I.e. The real capacitors cost a small fortune to buy genuine ones, from real suppliers, ready for your online shop, to sell them. But talk is cheap, so saying "100% genuine", costs nothing to say it, even if it isn't necessarily true.Have you got any left ?A good quality picture here and/or proper testing of unused ones, might reveal the truth.

author: madires
author_rank: Super Contributor
timestamp: February 23, 2021, 12:40:59 pm
content: Quote from: PKTKS on February 23, 2021, 12:12:16 pmHalf-bridge != flyback. Please see-https://www.smps.us/topologies.html-http://ww1.microchip.com/downloads/en/appnotes/01114a.pdf-https://en.wikipedia.org/wiki/Switched-mode_power_supply

author: PKTKS
author_rank: Super Contributor
timestamp: February 23, 2021, 12:47:21 pm
content: Quote from: madires on February 23, 2021, 12:40:59 pmActually they are.HALF BRIDGES and PUSH-PULL .. and FULL BRIDGES..they all are topologies of flyback converters.If some recent post 90s links on the net are telling differentthings... really.. I Don't give a shit.Enough to observe they are messing the so called"offline" type (or "flyback") with the whole class itself.I won't even bother ..But frankly .. that is non sense and changes over timecf. industry momentum and new comers...Terms like "links" were related to chainsand fake news... to our aunt chit chat..I don't give a shit if someone will call it FOO or F*** WITsPaul

author: wraper
author_rank: Unknown
timestamp: February 23, 2021, 12:57:53 pm
content: Quote from: PKTKS on February 23, 2021, 12:12:16 pmYou can post as many circuit diagrams as you want, but there is no "flyback" written there. Those in hardly readable TV circuit diagrams above most likely have flyback topology, but it has nothing to do with half-bridge ATX PSU schematic you posted later and which is not flyback. BTW don't press "ENTER" key when typing, it's a bad habit and it's annoying to read poorly formatted narrow text.

author: PKTKS
author_rank: Super Contributor
timestamp: February 23, 2021, 01:03:28 pm
content: Well you can always ask someone more familiar than yourselfto write words.. F_L_Y_B_A_C_K in bold letters...to satisfy you personally .. any repairman will just tellyou: yes that is the flyback.. what f*** doubt is that?laughs are guaranteed

author: wraper
author_rank: Unknown
timestamp: February 23, 2021, 01:13:45 pm
content: Quote from: PKTKS on February 23, 2021, 01:03:28 pmI ask fora singlereference where is said that any isolated SMPS is "flyback". Just think a bit about meaning words "fly-back". It makes no sense whatsoever to apply it to isolated SMPS in general. BTW there actually is flyback SMPS in that ATX circuit. It's a small 5V standby PSU. But it has nothing to do with high power half-bridge part.

author: madires
author_rank: Super Contributor
timestamp: February 23, 2021, 01:26:05 pm
content: PKTKS, when looking at schematics have you noticed the little dot at each transformer winding to indicate its direction? Have a look at the ATX schematic you've posted earlier. Do you notice a difference between the secondary windings of the transformers for the 5V standby and the main outputs?

author: PKTKS
author_rank: Super Contributor
timestamp: February 23, 2021, 01:40:12 pm
content: Quote from: madires on February 23, 2021, 01:26:05 pmAs you may have noticed by my typos and stuff..I am deeply buried into a lot of stuff..I pride myself as having it organized enough through out the 70sup to today.. thousands of schemas papers and academia..NO I have not even overlooked them because I have themin memory over extensive use...But anyone is very welcome to contact me asking for somespecific schema or such.. I have over 10.000 70s 80s 90sCRTs VCRs Monitors.. all in original Service Manual fromdirect fabs resellers..No they are not scanned. I stopped servicing CRTs/VCRs late 80sspecialized myself in computers mostly PCsWhich I also have a ton of stuff in AT and ATX spread around..Having a specific reference.. you can surely post on eevb..as soon as noticed I answer gladlyIf some detail here I can crop a high quality part as wellPaul

author: NOCTURNE
author_rank: Contributor
timestamp: February 23, 2021, 02:20:24 pm
content: Quotewell try to find or get some soonQuotehow should i properly test them?

author: bdunham7
author_rank: Super Contributor
timestamp: February 23, 2021, 02:45:32 pm
content: Quote from: NOCTURNE on February 22, 2021, 11:28:27 pmI'm not sure what the marketplace is like there. If you replace caps again, perhaps try a better model from a lower tier company as those are really unlikely to be fake. Like Teapo or SamXon or Lelon...QuoteIt's very hard to know what is going on if you can't measure it. It is possible there is some other issue with your PSU but I have no idea what it might be. Even crappy PSUs typically work for quite a while if they aren't heavily loaded. You could try adding smaller capacitors at the HDD connector on the 5V and 12V lines.Your English is fine. Better than my Farsi!

author: MK14
author_rank: Super Contributor
timestamp: February 23, 2021, 02:46:51 pm
content: Quote from: NOCTURNE on February 23, 2021, 02:20:24 pmIt is difficult to test them, especially properly/fully. Which is part of the reason, why on balance and with experience, many people go for reliable/trustworthy suppliers. Which solves that problem for them.In some cases, fake capacitors can have significantly different values, to the real genuine component. So, it may claim 1,000 uF, when it is really a 330 uF inside the case, or a 16V rated capacitor, in a 50V rated one. Etc etc.From youtube videos I've seen, of fake capacitors. They seem to use flakey/second-hand/old and/or cheap branded (Chinese) capacitors, which they then re-cover in a thin plastic film. With markings on it, to look like a proper/expensive/quality capacitor brand, with recent date markings.

author: wraper
author_rank: Unknown
timestamp: February 23, 2021, 02:47:56 pm
content: I would not exclude it was a bad cable/sata power connector and reattaching it solved the issue for a while.

author: bdunham7
author_rank: Super Contributor
timestamp: February 23, 2021, 03:44:40 pm
content: Quote from: PKTKS on February 23, 2021, 11:05:12 amYou can use the term 'flyback' for anything you want, but the rest of us think the term refers specifically to a system that stores the energy in the core of the transformer during the transfer process.As to your scenario, I don't see what it has to do with the very short current spikes or HF ripple that I thought this topic was about. And if you 'assume a glitch on the mains', what do you expect? I will concede that a booster is a poor dynamic current sourcewithout the mains input.

author: NOCTURNE
author_rank: Contributor
timestamp: February 23, 2021, 06:31:04 pm
content: Quote from: bdunham7 on February 23, 2021, 02:45:32 pmyeah, the idea of getting cheaper caps is way better than getting a branded fake. I will consider thatQuotebefore getting the last caps which are already in the PSU I did this and it worked for 3 mountsQuoteI'm glad heard you can speak itQuote from: MK14 on February 23, 2021, 02:46:51 pmThe only most legit way I found is checking the ESR value with LCR or Esr meter which I don't have.and as far as measuring capacitance value goes I did that with a multimeter I checked all of them before soldering, and they all were fine and in range of marked capacitance but it still doesn't mean they were totally fine.this video you linked is showing 6800uf caps this kind of caps are more expensive than small ones and scammers aiming at the market of these caps more. I have a picture here just for funin another Farsi forum two-person recommended me, test snubber circuits I have to test them under load condition?

author: wraper
author_rank: Unknown
timestamp: February 23, 2021, 08:22:21 pm
content: ESR meter is not very useful for spotting fakes unless they are extremely bad. You need a very precise ESR meter to spot fakes with some confidence, but it still will be good only enough to spot some fakes, not to guarantee genuine. As said, post some photos of capacitors from different angles (top, bottom, side).QuoteThey counterfeit any capacitance. Large capacitors are often recycled e-waste. Small capacitors usually are brand new fakes from the factory.

author: NOCTURNE
author_rank: Contributor
timestamp: February 23, 2021, 09:35:46 pm
content: Quote from: wraper on February 23, 2021, 08:22:21 pmQuoteyou mean they just show correct capacitance on multimeter while their actually cannot achieve that?Quotemeanwhile, I cannot open PSU. but will check this photo with mine when just opened it it should be identical to those are I bought; this is from their online shop

author: wraper
author_rank: Unknown
timestamp: February 23, 2021, 09:47:02 pm
content: Quote from: NOCTURNE on February 23, 2021, 09:35:46 pmLook legit.

author: MK14
author_rank: Super Contributor
timestamp: February 23, 2021, 10:33:16 pm
content: I can't be 100% sure, and could be wrong. But they do seem to be fakes to me.Look at the leads. What a mess. They look like someone has used a poor quality pair of pliers, to quickly pull them into that shape. So many kinks and dents in those leads. There are so many apparent inconsistencies in the fonts, with those capacitors. The uF is almost (or is) touching or even smudged together. Yet the 35 V bit has a huge gap between the characters.There is a '+' in the temperature characters, which maybe shouldn't even be there. It looks rather messy.Example:Original Source:https://silmic.ir/wp-content/uploads/2018/02/28-600x600.jpg

author: NOCTURNE
author_rank: Contributor
timestamp: February 23, 2021, 10:35:57 pm
content: this is my PSU when the first time I opened it can somebody tell me what those caps using for in PSU I marked with red. I am listing their characteristics here but I don't know which one is for which cap in the picture. thanks100uf 16v 2x220uf 25v 3x2.2uf 50v 4xyou can load full resolution

author: NOCTURNE
author_rank: Contributor
timestamp: February 23, 2021, 10:43:33 pm
content: Quote from: MK14 on February 23, 2021, 10:33:16 pmwas an interesting investigation young sherlockyou are right but I don't know why they put this on the website maybe they didn't have another sample? because this caps seems second-handed or was def in circuit board before

author: wraper
author_rank: Unknown
timestamp: February 23, 2021, 11:20:57 pm
content: They call NHG as LOW ESR, they are not. It's general porpose series. They have NHG which look fine and which look dodgy. Besides questionable marking, their shape is suspicious and one was deformed during production. Sadly vent shape is not visible. Also Panasonic stopped using M logo quite a while ago so those certainly are not fresh.