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Recapping Jeantech JNP-400P

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    #1

    Recapping Jeantech JNP-400P

    Hello again

    I am rebuilding a older system and would like to keep this PSU with it but it is a little tired being ten years old and caps around the 5Vsb were bulging.

    I have most caps in stock so will recap it.

    The issue I wanted to address is it seems to only have one 16V cap, is this right that all the 12V filtering is done by a single cap? I have annotated the attached picture.

    If the two 3300uf 10V caps really are just for 5V am I ok to use 6.3V due to size issues? Just wanted to check never seen a PSU of reasonable quality with just a single cap for 12V filtering, usually they have more.

    Most parts I will use Panasonic FR apart from the 2200uf 16V where I will use FK.



    Thanks for any help.
    Attached Files
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    #2
    Re: Recapping Jeantech JNP-400P

    Take a look at the backside.

    But it looks like a rather old PSU. Manufacturer could be High Power.
    It looks like that tiny 10uF/50V Cap could be for +12V as well...

    As for Voltage: I've seen 6,3V Caps on some PSUs, but those ones usually have problems with the Lifetime of the caps. Like some FSP units. So I woudn't do it, if at all avoidable.

    Caps in those sizes aren't easy to obtain, but Mouser has some 10mm 10V/2700uF caps. I'd use one of those (Nippon KYB) instead of a 3300uF cap.

    But remember:
    This one is a 300W PSU! Treat it as one!

    Comment

      #3
      Re: Recapping Jeantech JNP-400P

      Originally posted by Stefan Payne View Post
      But remember:
      This one is a 300W PSU! Treat it as one!
      Are you sure? The wattage on the label adds up to 406W
      Main rig:
      Gigabyte B75M-D3H
      Core i5-3470 3.60GHz
      Gigabyte Geforce GTX650 1GB GDDR5
      16GB DDR3-1600
      Samsung SH-224AB DVD-RW
      FSP Bluestorm II 500W (recapped)
      120GB ADATA + 2x Seagate Barracuda ES.2 ST31000340NS 1TB
      Delux MG760 case

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        #4
        Re: Recapping Jeantech JNP-400P

        Could that small cap be swapped for a larger? There is space on the silk screen.
        Attached Files

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          #5
          Re: Recapping Jeantech JNP-400P

          Recapped this and while I have a perfect 5vsb the PSu will not power. Jumper trick and no action.

          Ideas? Everything looks ok not sure what I have done

          Comment

            #6
            Re: Recapping Jeantech JNP-400P

            Did this power supply work before changing capacitors? You may have installed a bad capacitor or you may have a solder bridge in the area where you were soldering.

            You mentioned bulging capacitors in the 5vsb circuit. There may be other problems with this circuit. Looks like the old two transistor type of circuit, and they can be tricky. Start by checking the 5 volts on the 5vsb circuit. If it is not working, nothing else will work. So make sure that you have 5 volts in the 5vsb circuit.
            Old proverb say.........If you shoot at nothing, you will hit nothing (George Henry 10-14-11)

            Comment

              #7
              Re: Recapping Jeantech JNP-400P

              I think he already verified that he has +5VSB.

              And yup, that's definitely a Sirtec / High Power PSU. It's a half-bridge unit with the "classic" 10uF 50V and 16V capacitor PI filter arrangement for +12V that Sirtec PSUs are known for, as Stefan said. It looks like that 10uF 50V capacitor is actually silkscreened for a much larger capacitor. You said you recapped it with Panasonic FR and FK. I don't think these Sirtec PSUs will tolerate anything lower than entry-level parts (at least on +12V) without oscillating, but I could be wrong on this particular design. Did you replace the tiny Teapo SEK by the supervisory (SG6105DZ) chip? If one of those needs to pass a signal for the PS-ON circuit to work and they're all dried up (or haven't been replaced?), the PSU won't start (at least on a motherboard - using the jumper trick could change that). I would also recommend checking and/or re-touching up the solder joints. I also couldn't help but notice the "conductive" glue this PSU uses. If it started to turn black (I can see some doing that on one of the output load resistors), it could be shorting something out in the PSU.

              I also see a couple ventless Teapo SEK used to bias the Bipolar switching transistors. If those are bad (or rather, haven't been replaced), the PSU definitely won't start at all. You said you have +5VSB, so the problem lies elsewhere. If you've verified none of the above is an issue, the output rectifiers would be the next components to check. I have to ask, did you try putting some load on the PSU (a hard drive, fan, disc drive, etc...) with the jumper trick? Some PSUs won't start without any load. This PSU seems to use minimum load resistors on the output so that may not be it either.
              Last edited by Wester547; 04-23-2017, 09:26 AM.

              Comment

                #8
                Re: Recapping Jeantech JNP-400P

                It was the caps I used for the Standby, I was thrown off when the standby itself was fine but wouldn't power on.

                Lesson learned!

                Thanks for the input, always appreciated.

                Comment

                  #9
                  Re: Recapping Jeantech JNP-400P

                  This power supply is not suitable for any 12V CPU. It is designed for 5V CPUs, Pentium 3, Athlon XP etc.

                  I tried it with several P4 systems and it would always oscillate.

                  More info here:
                  https://www.badcaps.net/forum/showthread.php?t=23996
                  https://www.badcaps.net/forum/showthread.php?t=24101
                  https://www.badcaps.net/forum/showpo...&postcount=288

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