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    #1

    Mediasonic H8R2-SU3S2 Power Supply Help

    Hey everyone, been a while. Anyway I took this PSU out of a used RAID enclosure and wish to use it to power some hard drives independent of that system. When I plug it in to power, the 5V rail works perfectly (so if I connect a laptop drive it spins up) but the 12V rail doesn't work (so a desktop drive doesn't spin up). I sort of guessed that the blue wire is some sort of control, but grounding it makes no difference. At least before I took it apart, I know the PSU did work, as when I inserted a desktop hard drive enclosure into the RAID enclosure it did spin up. Now that I've chopped all the wiring I can't exactly test it again, but I'm making the assumption I didn't short anything to destroy the 12V rail. Any help appreciated!


    TLDR: As soon as I plug it in to power the 5V rail puts out 5V but no matter whether blue wire is grounded or not the 12V rail never works.
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    #2
    Re: Mediasonic H8R2-SU3S2 Power Supply Help

    Hmmm, it looks like it has active PFC and two separate inverters, one for each output. If they are two inverters, they are also flyback type, based on the lack of output inductors. And if two inverters, one evidently works, while the other, possibly the one with the larger transformer, is not. If one works that suggests the active PFC does also. If there are two inverters, one working, the other might be as "simple" as a shorted output cap or rectifier.

    I hope at least some of this thinking out loud is helpful.
    PeteS in CA

    Power Supplies should be boring: No loud noises, no bright flashes, and no bad smells.
    ****************************
    To kill personal responsibility, initiative or success, punish it by taxing it. To encourage irresponsibility, improvidence, dependence and failure, reward it by subsidizing it.
    ****************************

    Comment

      #3
      Re: Mediasonic H8R2-SU3S2 Power Supply Help

      Originally posted by PeteS in CA View Post
      Hmmm, it looks like it has active PFC and two separate inverters, one for each output. If they are two inverters, they are also flyback type, based on the lack of output inductors. And if two inverters, one evidently works, while the other, possibly the one with the larger transformer, is not. If one works that suggests the active PFC does also. If there are two inverters, one working, the other might be as "simple" as a shorted output cap or rectifier.

      I hope at least some of this thinking out loud is helpful.

      I appreciate your reply, I mean it's helpful in that I understand more about the power supply. However, I figured out the problem. If I put the blue wire to 5V the 12V rail starts up so that seems to be the key. All is well now.


      Thank you

      Comment

        #4
        Re: Mediasonic H8R2-SU3S2 Power Supply Help

        When in doubt: experiment.

        A colleague and I at my old job always used to joke with that, because the OSHA training we took had some really funny (basic) questions sometimes. One of them was something along the lines of, if you're dealing with a possibly hazardous situation, what should you do? The correct answer was ask your supervisor. But the incorrect answers were often either really obviously wrong or just plain funny. This one stuck with us for a while. So every time we had to make a repair on site and didn't have the right tools or couldn't figure it out, we'd always joke we just needed to experiment more... and often that's what our supervisor told us to do anyways (or did with us.)

        Originally posted by PeteS in CA View Post
        Hmmm, it looks like it has active PFC and two separate inverters, one for each output.
        Yup, that looks correct to me. Seems the 12V rail (or actually what looks like two 12V rails) come out of the bigger transformer, and the 5V/5VSB (possibly combined into one) comes out of the smaller transformer... which is rather strange why they have it like this. I guess that means the HDDs are always fed 5V?

        Ah whatever, it works, so I guess we can let it be.
        Last edited by momaka; 05-26-2021, 09:36 PM.

        Comment

          #5
          Re: Mediasonic H8R2-SU3S2 Power Supply Help

          Originally posted by momaka View Post
          When in doubt: experiment.

          A colleague and I at my old job always used to joke with that, because the OSHA training we took had some really funny (basic) questions sometimes. One of them was something along the lines of, if you're dealing with a possibly hazardous situation, what should you do? The correct answer was ask your supervisor. But the incorrect answers were often either really obviously wrong or just plain funny. This one stuck with us for a while. So every time we had to make a repair on site and didn't have the right tools or couldn't figure it out, we'd always joke we just needed to experiment more... and often that's what our supervisor told us to do anyways (or did with us.)


          Yup, that looks correct to me. Seems the 12V rail (or actually what looks like two 12V rails) come out of the bigger transformer, and the 5V/5VSB (possibly combined into one) comes out of the smaller transformer... which is rather strange why they have it like this. I guess that means the HDDs are always fed 5V?

          Ah whatever, it works, so I guess we can let it be.

          Yes it is rather weird. 5v is always alive. When I connect a laptop drive it is always spinning. While the fans which I connected to 12v and desktop drives are switched. I wonder if this is harmful for the hard drives?

          Comment

            #6
            Re: Mediasonic H8R2-SU3S2 Power Supply Help

            Dumb question time, HDD motors run off the 5V? I always ASSumed the 12V was for the motor and the 5V for the interface logic.

            Are you still dwelling in the North Bay shove?
            PeteS in CA

            Power Supplies should be boring: No loud noises, no bright flashes, and no bad smells.
            ****************************
            To kill personal responsibility, initiative or success, punish it by taxing it. To encourage irresponsibility, improvidence, dependence and failure, reward it by subsidizing it.
            ****************************

            Comment

              #7
              Re: Mediasonic H8R2-SU3S2 Power Supply Help

              Originally posted by shovenose View Post
              Yes it is rather weird. 5v is always alive. When I connect a laptop drive it is always spinning. While the fans which I connected to 12v and desktop drives are switched. I wonder if this is harmful for the hard drives?
              I suppose not if that's how the RAID enclosure ran the drives all along... but I do think it's a bit sketchy, personally. They should have at least added a MOSFET and control line for the HDD's 5V rail so that both 12V and 5V could be switched.

              Originally posted by PeteS in CA View Post
              Dumb question time, HDD motors run off the 5V? I always ASSumed the 12V was for the motor and the 5V for the interface logic.
              For desktop / 3.5" HDD, YES, 12V is used for the motor and 5V for the interface.
              But for laptop / 2.5" HDDs, 5V is used for everything, and 12V is not used.

              BTW, what's with all of the spam bots that were posting in this thread last night? My email got filled with notifications from this and a few other threads. Hope they're gone for good.

              Comment

                #8
                Re: Mediasonic H8R2-SU3S2 Power Supply Help

                Originally posted by momaka View Post
                I suppose not if that's how the RAID enclosure ran the drives all along... but I do think it's a bit sketchy, personally. They should have at least added a MOSFET and control line for the HDD's 5V rail so that both 12V and 5V could be switched.


                For desktop / 3.5" HDD, YES, 12V is used for the motor and 5V for the interface.
                But for laptop / 2.5" HDDs, 5V is used for everything, and 12V is not used.

                BTW, what's with all of the spam bots that were posting in this thread last night? My email got filled with notifications from this and a few other threads. Hope they're gone for good.

                I wonder if, perhaps, on the original controller, the 5V is switched... who knows. I think I threw it away already.

                Comment

                  #9
                  Re: Mediasonic H8R2-SU3S2 Power Supply Help

                  Originally posted by shovenose View Post
                  I wonder if, perhaps, on the original controller, the 5V is switched...
                  Good call. Could be!

                  Originally posted by shovenose View Post
                  I think I threw it away already.
                  master hoarder is displeased!
                  Last edited by momaka; 05-28-2021, 12:10 PM.

                  Comment

                    #10
                    Re: Mediasonic H8R2-SU3S2 Power Supply Help

                    Originally posted by momaka View Post
                    Good call. Could be!


                    master hoarder is displeased!

                    You don't want to see my place or my car... It's pretty bad already. Last thing I need is more shit.

                    Comment

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