Announcement

Collapse
No announcement yet.

Replacing unknown NTC Thermistor in Corsair CX400

Collapse
X
 
  • Filter
  • Time
  • Show
Clear All
new posts

    Replacing unknown NTC Thermistor in Corsair CX400

    A few days ago, something in my lounge started making a loud "phut" noise when plugged into the wall, and sometimes a smell like a hot glue gun was present in the room momentarily.

    I tracked it down to the NTC thermistor in my Corsair CX400. It has cracked and burnt. It measures 50kOhm+ cold... strangely, the PSU still seemed to work fine the whole time (?), so shorted MOSFETs or such seem unlikely!


    The problem is that the damage to the thermistor has resulted in the part number becoming unreadable, save the "SCK" on top.

    Does anyone know the value of the thermistor used in the CX400, or can advise on how to pick a suitable replacement? I did find a thread on the Corsair forums: http://forum.corsair.com/v3/showthread.php?t=112161 but nobody answered.

    How similar does a replacement have to be? I do have some pulled thermistors from scrapped PSUs. An SCK 054, a CT 5D-11, and a DSC 8D-11.
    Attached Files
    "Tantalum for the brave, Solid Aluminium for the wise, Wet Electrolytic for the adventurous"
    -David VanHorn

    #2
    Re: Replacing unknown NTC Thermistor in Corsair CX400

    What is the diameter of that NTC? 10mm?

    SCK 054 looks to be about right.
    You can put that 054 in and run at full load and check the temperature and Vdrops on that 054 to see what you get.
    Never stop learning
    Basic LCD TV and Monitor troubleshooting guides.
    http://www.badcaps.net/forum/showthr...956#post305956

    Voltage Regulator (LDO) testing:
    http://www.badcaps.net/forum/showthr...999#post300999

    Inverter testing using old CFL:
    http://www.badcaps.net/forum/showthr...er+testing+cfl

    Tear down pictures : Hit the ">" Show Albums and stories" on the left side
    http://s807.photobucket.com/user/budm/library/

    TV Factory reset codes listing:
    http://www.badcaps.net/forum/showthread.php?t=24809

    Comment


      #3
      Re: Replacing unknown NTC Thermistor in Corsair CX400

      Yes it's a 10mm NTC.
      Interestingly, a similarly rated Enermax Liberty 400W uses an SCK 053.

      I've put the spare SCK 054 in, and it seems to be working OK so far.
      Hard to check full load though as I don't have a load tester to be sure of the load.
      "Tantalum for the brave, Solid Aluminium for the wise, Wet Electrolytic for the adventurous"
      -David VanHorn

      Comment


        #4
        Re: Replacing unknown NTC Thermistor in Corsair CX400

        is there any info for calculating the right NTC for a specific run-load??

        Comment


          #5
          Re: Replacing unknown NTC Thermistor in Corsair CX400

          There is http://www.ametherm.com/inrush-curre...t-limiter.html
          I don't know if that helps though.

          I think it would require extensive knowledge of the PSU characteristics?
          Last edited by Agent24; 09-30-2017, 08:34 PM.
          "Tantalum for the brave, Solid Aluminium for the wise, Wet Electrolytic for the adventurous"
          -David VanHorn

          Comment


            #6
            Re: Replacing unknown NTC Thermistor in Corsair CX400

            You usually start with your max. inrush current and the cold resistance of the NTC. To not blow the fuse or kill the bridge rectifier. 10ohms is what I'm used to seeing.
            Next is the max. load current, so PTC does not burn up. This is a size thing. Bigger is better but slower to heat up.

            Note OP's power supply had heat shrink around it, this I believe is done to keep the NTC hot despite airflow from the PSU fan. If the NTC is a bit cool, larger voltage drop during run.

            Comment


              #7
              Re: Replacing unknown NTC Thermistor in Corsair CX400

              VI characteristic chart showing the the Vdrops, Current, Pd, ETC.
              As you can see from the graph for 504
              @4A rated current the resistance is a little < 0.20 Ohms, Vdrops is about 0.70V, the power dissipation a little > 2W
              Attached Files
              Never stop learning
              Basic LCD TV and Monitor troubleshooting guides.
              http://www.badcaps.net/forum/showthr...956#post305956

              Voltage Regulator (LDO) testing:
              http://www.badcaps.net/forum/showthr...999#post300999

              Inverter testing using old CFL:
              http://www.badcaps.net/forum/showthr...er+testing+cfl

              Tear down pictures : Hit the ">" Show Albums and stories" on the left side
              http://s807.photobucket.com/user/budm/library/

              TV Factory reset codes listing:
              http://www.badcaps.net/forum/showthread.php?t=24809

              Comment


                #8
                Re: Replacing unknown NTC Thermistor in Corsair CX400

                Originally posted by redwire View Post
                Note OP's power supply had heat shrink around it, this I believe is done to keep the NTC hot despite airflow from the PSU fan. If the NTC is a bit cool, larger voltage drop during run.
                Wouldn't the higher Vdrop just cause more heating and balance out the cooling from the fan anyway?

                My guess was that the heatshrink was a safety idea in case of failure, as happened here. Like how they use glass fuses with heatshrink around them, instead of getting ceramic ones.
                "Tantalum for the brave, Solid Aluminium for the wise, Wet Electrolytic for the adventurous"
                -David VanHorn

                Comment


                  #9
                  Re: Replacing unknown NTC Thermistor in Corsair CX400

                  I think you're right, the heatshrink sleeve is probably about safety; heating the NTC more would lower losses but who cares about a watt or two lost here.

                  The cheese-cloth (fire) test means spitting sparks out the vents is not OK, so I notice you don't always see a heatshrink cover on inrush limiter, MOV in Channel Well Technology (CWT) PSU's. Mostly silicone glue if it is a spacings issue.

                  Regulatory agencies don't permit heatshrink over MOV's/inrush limiters because of melting, flammability and dielectric rating - but not a worry here because of this metal enclosure. As long as the flames stay inside.

                  The ripple current through the part has high peaks and yet you want the average current to be in spec.
                  SCK10 are rated for about 330uF at 240VAC. Another SCK datasheet

                  CX600M 600W; APFC 270uF; two of SCK015 (10mm, 1R cold, 5A)
                  RMX650i 650W; APFC 680uF; one of SCK035 (10mm, 3R cold, 5A)

                  Comment


                    #10
                    Re: Replacing unknown NTC Thermistor in Corsair CX400

                    If the efficiency is marginal, perhaps that watt or two is the difference between 80Plus or not...?

                    http://www.tomshardware.com/reviews/...s,2746-18.html says CX400 had 63.5A inrush current on 240v, that implies ~4Ohm cold NTC?
                    "Tantalum for the brave, Solid Aluminium for the wise, Wet Electrolytic for the adventurous"
                    -David VanHorn

                    Comment


                      #11
                      Re: Replacing unknown NTC Thermistor in Corsair CX400

                      Originally posted by Agent24 View Post
                      If the efficiency is marginal, perhaps that watt or two is the difference between 80Plus or not...?

                      http://www.tomshardware.com/reviews/...s,2746-18.html says CX400 had 63.5A inrush current on 240v, that implies ~4Ohm cold NTC?
                      100A of inrush allowed by ATX 2.2 spec at 230V? Wouldn't that cause most circuit breakers in the EU to trip? IIRC, they don't even allow as much amps as the Americas!

                      In fact, the higher normal-voltage nations seem to prefer smaller-diameter wiring and use higher voltage to make up for the copper limitations, IIRC...
                      Last edited by RJARRRPCGP; 10-01-2017, 07:44 PM.
                      ASRock B550 PG Velocita

                      Ryzen 9 "Vermeer" 5900X

                      16 GB AData XPG Spectrix D41

                      Sapphire Nitro+ Radeon RX 6750 XT

                      eVGA Supernova G3 750W

                      Western Digital Black SN850 1TB NVMe SSD

                      Alienware AW3423DWF OLED




                      "¡Me encanta "Me Encanta o Enlistarlo con Hilary Farr!" -Mí mismo

                      "There's nothing more unattractive than a chick smoking a cigarette" -Topcat

                      "Today's lesson in pissivity comes in the form of a ziplock baggie full of GPU extension brackets & hardware that for the last ~3 years have been on my bench, always in my way, getting moved around constantly....and yesterday I found myself in need of them....and the bastards are now nowhere to be found! Motherfracker!!" -Topcat

                      "did I see a chair fly? I think I did! Time for popcorn!" -ratdude747

                      Comment


                        #12
                        Re: Replacing unknown NTC Thermistor in Corsair CX400

                        Originally posted by RJARRRPCGP View Post
                        100A of inrush allowed by ATX 2.2 spec at 230V? Wouldn't that cause most circuit breakers in the EU to trip? IIRC, they don't even allow as much amps as the Americas!

                        In fact, the higher normal-voltage nations seem to prefer smaller-diameter wiring and use higher voltage to make up for the copper limitations, IIRC...
                        If the inrush duration is less than the trip curve of the circuit breaker then the circuit breaker will not trip.


                        Fuse curves:
                        https://cdn.badcaps-static.com/pdfs/...c9cccf3656.pdf
                        Last edited by budm; 10-01-2017, 09:04 PM.
                        Never stop learning
                        Basic LCD TV and Monitor troubleshooting guides.
                        http://www.badcaps.net/forum/showthr...956#post305956

                        Voltage Regulator (LDO) testing:
                        http://www.badcaps.net/forum/showthr...999#post300999

                        Inverter testing using old CFL:
                        http://www.badcaps.net/forum/showthr...er+testing+cfl

                        Tear down pictures : Hit the ">" Show Albums and stories" on the left side
                        http://s807.photobucket.com/user/budm/library/

                        TV Factory reset codes listing:
                        http://www.badcaps.net/forum/showthread.php?t=24809

                        Comment


                          #13
                          Re: Replacing unknown NTC Thermistor in Corsair CX400

                          Originally posted by RJARRRPCGP View Post
                          100A of inrush allowed by ATX 2.2 spec at 230V? Wouldn't that cause most circuit breakers in the EU to trip? IIRC, they don't even allow as much amps as the Americas!
                          Yes, they would.

                          Normal Ratings are B16 breakers wich allow only 3-5 times the nominal value.
                          Wich means that everything over 48A is crap and trips breaker (hello Sirfa!!)
                          And max is 80A.

                          However there is also the possibility to install a C16 breaker that allows 5-10 times the nominal value (=80-160A), but depending on the length of the cable it's not always possible.

                          And they are expensive as hell. At least double the price of a normal B16.
                          I've paid about tripple what a normal B16 breaker whould have cost....

                          That sounds like much but a B16 breaker cost as little as ~2€.
                          And I've paid ~9€ for one (Hager) C16...

                          Originally posted by RJARRRPCGP View Post
                          In fact, the higher normal-voltage nations seem to prefer smaller-diameter wiring and use higher voltage to make up for the copper limitations, IIRC...
                          First 1,5mm² copper wire is the norm here in Europe (German)
                          That is somewhat between AWG15 and AWG16...

                          Second: Normal breakers for that (as far as I know) is 16A with the B characteristics.
                          Although I've heard that 13A is the new norm and 16A is only allowed under certain conditions.

                          Third: In some regions like the old Communist Germany 10A are also used - with Aluminium wire. I can't say anything about that, never seen it, that's only what I've heard...
                          Last edited by Stefan Payne; 10-01-2017, 11:21 PM.

                          Comment


                            #14
                            Re: Replacing unknown NTC Thermistor in Corsair CX400

                            Originally posted by Agent24 View Post
                            Does anyone know the value of the thermistor used in the CX400, or can advise on how to pick a suitable replacement? I did find a thread on the Corsair forums: http://forum.corsair.com/v3/showthread.php?t=112161 but nobody answered.
                            Well, looks like you found your solution more or less.

                            Nonetheless, I can't help but note that your CX400 looks very much like the Season S12II platform. In fact, the layout looks almost like an exact copy of my Antec Earthwatts EA-430 and EA-500 PSUs. So if you ever need any parts numbers off of those, let me know.

                            Comment


                              #15
                              Re: Replacing unknown NTC Thermistor in Corsair CX400

                              Yes, it does seem like the SCK 054 is a fair choice. It hasn't exploded so far anyway, and the PSU seems to be operating normally.

                              Thanks for the offer. I'm hoping it will be fairly reliable if it is based on Seasonic. I think the first run of Corsair's PSUs were quite good, then quality fell away when they switched to a cheaper OEM?
                              "Tantalum for the brave, Solid Aluminium for the wise, Wet Electrolytic for the adventurous"
                              -David VanHorn

                              Comment


                                #16
                                Re: Replacing unknown NTC Thermistor in Corsair CX400

                                Originally posted by momaka View Post
                                Nonetheless, I can't help but note that your CX400 looks very much like the Season S12II platform.
                                Because it is.
                                Corsair had to take some shit when they broght the CX430 based on some CWT plattform instead, because people think the CWT plattform is inferior to the Seasonic one...

                                Originally posted by Agent24 View Post
                                I'm hoping it will be fairly reliable if it is based on Seasonic.
                                If that's the case it all depends on the component choice and how well all that stuff is calculated and implemented.
                                The Manufacutrer of the Plattform doesn't hav much to do with it...


                                Originally posted by Agent24 View Post
                                I think the first run of Corsair's PSUs were quite good, then quality fell away when they switched to a cheaper OEM?
                                That's what people say.
                                But I don't believe it anymore these days.

                                I think Seasonic as a contract manufacturer is the worst one of all...
                                I really don't understand why they are regarded that highly on the Interwebs.

                                CWT is a real contract manufacturer. You want something, you get what you paid for. That's it.
                                Seasonic does not do that.
                                They only do what they have, don't allow any other changes than the modular PCB. And also other stuff you don't want to know.

                                If the CX430 was cheaper than the CX400 is something you have to ask someone else. Its said that Seasonic is one of the more expensive manufacturers but also they aren't as good as people on the interwebs say they are.
                                CWT can do decent stuff and their soldering on the main PCB is rather good, but when it comes to handsoldering it can become rather ugly.



                                Still, there is a reason why so many people let their stuff be manufactured by CWT.
                                And there is a reason why there aren't any new Corsair, be quiet and Cooler Master PSU made by Seasonic these days.


                                PS: Please look for the protection chip.
                                Is it a HY-510N?? Seasonic seems to like this garbage protection IC...
                                Even in the 8pin world there are way better ones that support OCP on minor rails and/or UVP on +12V...

                                Comment


                                  #17
                                  Re: Replacing unknown NTC Thermistor in Corsair CX400

                                  Originally posted by Stefan Payne View Post
                                  I think Seasonic as a contract manufacturer is the worst one of all...
                                  I really don't understand why they are regarded that highly on the Interwebs.

                                  CWT is a real contract manufacturer. You want something, you get what you paid for. That's it.
                                  Seasonic does not do that.
                                  They only do what they have, don't allow any other changes than the modular PCB. And also other stuff you don't want to know.

                                  If the CX430 was cheaper than the CX400 is something you have to ask someone else. Its said that Seasonic is one of the more expensive manufacturers but also they aren't as good as people on the interwebs say they are.
                                  CWT can do decent stuff and their soldering on the main PCB is rather good, but when it comes to handsoldering it can become rather ugly.
                                  Just because Seasonic is terrible as a contractor doesn't mean they are a bad designer.

                                  They are probably doing that because they don't like to take a good design and turn it into garbage with bad components, just because some re-branding company asked them to in order to keep costs lower.

                                  Originally posted by Stefan Payne View Post
                                  Still, there is a reason why so many people let their stuff be manufactured by CWT.
                                  Most likely, that reason would be just price to performance ratio.
                                  CWT PSUs perform OK and cost a very reasonable price. But there is a third factor - reliability. On that front, I don't think CWT is doing so well. Again, they are OK, but not great. Meanwhile, most Seasonic designs are pretty rock solid in terms of lasting a good while.

                                  I was doing a PSU replacement for someone a few months back, and they said their PC is critical, so they didn't care much about the price on a new PSU, as long as it was reliable. The PC was a pretty basic one, with a single mid-range GPU and mid-range CPU - nothing power hungry. Yet, the Corsair CX that was in the rig was dead. It had little dust in it, so it wasn't that old.

                                  With reliability in mind, I grabbed what I thought was the best choice - a 650W Seasonic made by... well Seasonic. It was quite expensive for a 650W PSU - more than Corsair's and EVGA's 1000 Watt units. But then again, it also came with 10 years warranty. To have that kind of warranty, you can be sure as heck the PSU must be done well.

                                  Looking through the vents of that 650W Seasonic, everything was packed to the brim. It was actually just as heavy as a 1000W PSU. The primary had HUGE caps. Not that non-sense 400-500 uF I saw in my CWT-based Corsair CX750M and the 850 Watt Thermaltake Smart M series. Oh, and it had an 80+ Platinum rating, too.

                                  So in the end, you get what you pay for... (well, if you are lucky, as always. )
                                  Last edited by momaka; 10-08-2017, 10:16 AM.

                                  Comment


                                    #18
                                    Re: Replacing unknown NTC Thermistor in Corsair CX400

                                    Originally posted by momaka View Post
                                    They are probably doing that because they don't like to take a good design and turn it into garbage with bad components, just because some re-branding company asked them to in order to keep costs lower.
                                    No, I wasn't talking about "CHeaping out", I was talking about new ideas and other changes...

                                    Originally posted by momaka View Post
                                    But there is a third factor - reliability. On that front, I don't think CWT is doing so well. Again, they are OK, but not great. Meanwhile, most Seasonic designs are pretty rock solid in terms of lasting a good while.
                                    That's what you think.
                                    But try talking to eTailers. If you have connections they tell you a completely different story.
                                    Some of them seem to be very unhappy with Seasonics Return Rate...
                                    And here are also reasons for that.
                                    For example some people seem to be very unhappy with Seasonics Fans. And also coil whine could be a reason for that...
                                    Originally posted by momaka View Post
                                    I was doing a PSU replacement for someone a few months back, and they said their PC is critical, so they didn't care much about the price on a new PSU, as long as it was reliable. The PC was a pretty basic one, with a single mid-range GPU and mid-range CPU - nothing power hungry. Yet, the Corsair CX that was in the rig was dead. It had little dust in it, so it wasn't that old.
                                    Yes, but why talking about lower end/budget units when talking about reliability?!
                                    That should be a job for high end units...

                                    Originally posted by momaka View Post
                                    With reliability in mind, I grabbed what I thought was the best choice - a 650W Seasonic made by... well Seasonic. It was quite expensive for a 650W PSU - more than Corsair's and EVGA's 1000 Watt units. But then again, it also came with 10 years warranty. To have that kind of warranty, you can be sure as heck the PSU must be done well.
                                    Yes, and??
                                    Other manufacturer do have something similar. If you want to pay of course....

                                    But then again, there are many mentions of people on the Interwebs that report something like random shutdowns and such with Seasonic high End units (X/P Series)...


                                    Originally posted by momaka View Post
                                    Looking through the vents of that 650W Seasonic, everything was packed to the brim. It was actually just as heavy as a 1000W PSU. The primary had HUGE caps. Not that non-sense 400-500 uF I saw in my CWT-based Corsair CX750M and the 850 Watt Thermaltake Smart M series. Oh, and it had an 80+ Platinum rating, too.
                                    Yes, but why do you compare a high end unit that's always better than a lower end with a lower end unit where you have to meet some fixed price points to sell that unit. If you go over it, it doesn't sell at all anymore...

                                    The CX Series is something you should have compared to the S12II/M12II series.
                                    The X/P Series is something you should compare to Corsairs HX Platinum series. Maybe RMx Series.
                                    Originally posted by momaka View Post
                                    So in the end, you get what you pay for... (well, if you are lucky, as always. )
                                    Yes, and that's why you should compare low end with low end and high end with high end and not make some kind of cross comperation.

                                    With the low end, especially the "full Japanese" ones, you have to sacrifice on Bulk Capacitance. Or fan Quality, or both, to get to the price point you want.

                                    Take a look at be quiets Pure Power for example. Rather cheap caps, but bulk capacitance is in the right area for ofline UPS. And the fan is quite good as well.

                                    Now take a look at some competitors...
                                    Bulk Capacitance way off but 'Japanese' Bulk cap...
                                    And/or fan not as good.


                                    With higher end units like Bitfenix Whisper M, Corsair RMx and similar you have more room for better components than on low end units...


                                    And have you taken a look at the Focus Reviews @ Jonnyguru?
                                    One of them had some solder problems...
                                    Last edited by Stefan Payne; 10-09-2017, 04:34 PM.

                                    Comment


                                      #19
                                      Re: Replacing unknown NTC Thermistor in Corsair CX400

                                      Originally posted by Stefan Payne View Post
                                      That's what you think.
                                      But try talking to eTailers. If you have connections they tell you a completely different story.
                                      Some of them seem to be very unhappy with Seasonics Return Rate...
                                      And here are also reasons for that.
                                      For example some people seem to be very unhappy with Seasonics Fans. And also coil whine could be a reason for that...
                                      No, that's what I've seen working for a big national brick-n-mortar retailer here (no, not Worst Buy).

                                      Seems that CWT-built Corsair PSUs come back the most. Doesn't matter if it's the cheap CX---M platform or the "premium" HX. (Though I will note that Corsair and EVGA made up most of the PSU sales where I worked, so it is natural to see more of those come back). But EVGA, on the other hand, is doing okay, minus their low-end 400-500 Watt units, which seem to stop working for no reason.

                                      As for Seasonic coil whine - yeah, I've seen a few do it quite badly, but the PSUs seemed to be working fine otherwise. Actually, my Antec EarthWatts EA-500 has some pretty nasty coil whine too. But hey, at least it works. Just needed a recap. I'll take a recap job any day over a mystique design that quits for no reason one day (which seems to happen a lot more often to CWT).

                                      Originally posted by Stefan Payne View Post
                                      Yes, but why talking about lower end/budget units when talking about reliability?!
                                      That should be a job for high end units...
                                      Well, just because I am looking at a low end unit doesn't mean I should expect it to break after a year or two of use. I mean, it's okay if they used cheap caps in there to save on costs and it's okay if it's not the most efficient PSU or the most quiet one. But just because it's cheap doesn't mean it shouldn't still be fairly reliable. If I didn't care about reliability at all and just wanted something very cheap, I'd grab a Deer / Allied.

                                      Originally posted by Stefan Payne View Post
                                      The X/P Series is something you should compare to Corsairs HX Platinum series. Maybe RMx Series.
                                      The problem is Corsair HX is almost the same thing as CX---M, just with bigger and more components. Design-wise, they look too similar and HX still has the same crappy flat heatsinks that the CX---M has. To me, that's a definite low-ball in quality. Even a Gold rated 700W PSU will dissipate over 70 Watts of heat. Divide that into three heatsinks, and you get 23W on average per heatsink - which is a bit too much for a fin-less heatsink.

                                      Originally posted by Stefan Payne View Post
                                      And have you taken a look at the Focus Reviews @ Jonnyguru?
                                      One of them had some solder problems...
                                      Well, on that note, I'm no fan of CWT's nor Seasonic's soldering. I still have cuts from last week from handling that 850 Watt ThermalTake of mine. The S12II left my hands bleeding in a similar way while I was recapping it. Untrimmed leads + crummy solder joints tend to do that, though. On that note, everyone can take a moment to learn from Delta here, though Enhance and Seventeam are to be honorably mentioned as well.

                                      Anyways, all in all, I don't find Seasonic to be any worse than CWT. And I'll take Delta any day over these two.

                                      Comment


                                        #20
                                        Re: Replacing unknown NTC Thermistor in Corsair CX400

                                        Originally posted by momaka View Post
                                        Well, on that note, I'm no fan of CWT's nor Seasonic's soldering.
                                        It seems to be dependent on what you want and willing to pay for.
                                        Corsair units doesn't seem to be great in that regard, even for CWT Standards.
                                        If you know where to look for (hand soldered joints + primary daughterboard), you find some ugly parts...

                                        Though Bitfenix Whisper M seems quite well made, as does my CWT GPS one.


                                        Originally posted by momaka View Post
                                        On that note, everyone can take a moment to learn from Delta here, though Enhance and Seventeam are to be honorably mentioned as well.
                                        Sirfa also seems to be quite good.

                                        Astonishingly, HEC doesn't do too bad a job either...
                                        FSP is solala.

                                        CWT seems to be a hit or miss, depending on what you want and willing to pay for...
                                        They can be quite good, they can be quite bad...

                                        Originally posted by momaka View Post
                                        Anyways, all in all, I don't find Seasonic to be any worse than CWT. And I'll take Delta any day over these two.
                                        Who doesn't...
                                        But with Delta, if they put 1 cent too much Solder on one unit, they loose something around 100k or more a day. They are just that large.
                                        That's why it makes sense for them to have the best of the best soldering there is - not too much, not too little...

                                        For smaller manufacturers it doesn't matter that much...

                                        Comment

                                        Working...
                                        X