Center Pin Polarity Check?

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  • vestaviascott
    Senior Member
    • Aug 2018
    • 100
    • United States

    #1

    Center Pin Polarity Check?

    I've been buying and selling lots of used fitness equipment recently. It often happens that the power adapters are missing and the ones that have option to run off batteries are usually missing the battery cover.

    Ultimately, I end up purchasing a matching adapter for each unit prior to selling, however, just for checking the consoles pre-purchase, I think it would be helpful to have a "Universal" power adapter on hand.

    I've picked up one of these power adapters and it has removable tips that can be rotated to match the device's center pin polarity. However, without a manual for each device, what are the means to determine the polarity on site? I understand this specific device is limited to 2.1amps.

    Last edited by vestaviascott; 09-05-2018, 11:58 AM.
  • vestaviascott
    Senior Member
    • Aug 2018
    • 100
    • United States

    #2
    Re: Center Pin Polarity Check?

    Maybe this question could be better phrased:

    "Can the barrel/pin be checked with a multimeter to determine center pin polarity?"

    Comment

    • budm
      Badcaps Legend
      • Feb 2010
      • 40746
      • USA

      #3
      Re: Center Pin Polarity Check?

      You cannot tell the DC input jack polarity of the device without taking the device apart to be 100% sure unless it is printed on the device, and if the device is well built with protection, it should be able to protect itself from damage due to wrong polarity connection.
      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

      • vinceroger69
        Badcaps Legend
        • Mar 2012
        • 6714
        • uk

        #4
        Re: Center Pin Polarity Check?

        i would use a multi meter and use ground on one of the boards then test center or outer pins on the socket the main thing with that type of adapter does it provide enough amps?

        Comment

        • vinceroger69
          Badcaps Legend
          • Mar 2012
          • 6714
          • uk

          #5
          Re: Center Pin Polarity Check?

          Originally posted by budm
          You cannot tell the DC input jack polarity of the device without taking the device apart to be 100% sure unless it is printed on the device, and if the device is well built with protection, it should be able to protect itself from damage due to wrong polarity connection.
          what sort of amps on the adapter would these bikes use the one linked is 1.3amp is that enough?

          Comment

          • vestaviascott
            Senior Member
            • Aug 2018
            • 100
            • United States

            #6
            Re: Center Pin Polarity Check?

            Originally posted by vinceroger69
            ...the main thing with that type of adapter does it provide enough amps?
            The machine calls for 6v 2a power supply. The universal connector can output up to 2.1 amps.


            Originally posted by vinceroger69
            i would use a multi meter and use ground on one of the boards then test center or outer pins on the socket
            In the field (aka "thrift shop") I can't easily take the machines apart to ground to one of the internal boards. Is there an alternative for ground? One lead on center pin the other on outer barrell, take a resistance reading?

            Comment

            • budm
              Badcaps Legend
              • Feb 2010
              • 40746
              • USA

              #7
              Re: Center Pin Polarity Check?

              Always use the adapter that has at least 20% more current capability than the device requires.
              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

              • budm
                Badcaps Legend
                • Feb 2010
                • 40746
                • USA

                #8
                Re: Center Pin Polarity Check?

                Originally posted by vestaviascott
                The machine calls for 6v 2a power supply. The universal connector can output up to 2.1 amps.




                In the field (aka "thrift shop") I can't easily take the machines apart to ground to one of the internal boards. Is there an alternative for ground? One lead on center pin the other on outer barrell, take a resistance reading?
                I would do the research online to find out what the original power supply is capable of and it should also have polarity printed on the power supply itself. BTW, some of them may use AC output instead of DC, that is why you need to do research first.
                BTW, the center pin of typical 5.5 mm barrel may be 2.1mm or 2.5 mm so you need to verify that also since 2.5mm of the adapter will fit into 2.1mm pin but it will not make proper contact.
                Last edited by budm; 09-05-2018, 01:16 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

                • vinceroger69
                  Badcaps Legend
                  • Mar 2012
                  • 6714
                  • uk

                  #9
                  Re: Center Pin Polarity Check?

                  how i read that is the usb outlet is up too 2.1 amps?

                  Comment

                  • vestaviascott
                    Senior Member
                    • Aug 2018
                    • 100
                    • United States

                    #10
                    Re: Center Pin Polarity Check?

                    Originally posted by vinceroger69
                    what sort of amps on the adapter would these bikes use the one linked is 1.3amp is that enough?
                    In this case, its an elliptical machine that also takes 4 D batteries:



                    It calls for a 6v 2a adapter which I'm trying to replicate with the universal adapter.

                    The battery cover is missing so I can't easily connect the batteries, although I suppose I could use two wires to series connect both sets of batteries as the cover would otherwise be doing?

                    Comment

                    • budm
                      Badcaps Legend
                      • Feb 2010
                      • 40746
                      • USA

                      #11
                      Re: Center Pin Polarity Check?

                      Originally posted by vinceroger69
                      how i read that is the usb outlet is up too 2.1 amps?
                      That is correct. It is only rated at 1.3A (1300mA) @ 3 ~ 12V! as printed on the package.
                      2.1A for USB.
                      Last edited by budm; 09-05-2018, 01:20 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

                      • vinceroger69
                        Badcaps Legend
                        • Mar 2012
                        • 6714
                        • uk

                        #12
                        Re: Center Pin Polarity Check?

                        thanks budm i wasnt 100% sure if i was reading it correctly
                        Last edited by vinceroger69; 09-05-2018, 01:24 PM.

                        Comment

                        • vestaviascott
                          Senior Member
                          • Aug 2018
                          • 100
                          • United States

                          #13
                          Re: Center Pin Polarity Check?

                          Originally posted by budm
                          That is correct. It is only rated at 1.3A (1300mA) @ 3 ~ 12V! as printed on the package.
                          2.1A for USB.
                          Frick! I didn't catch that! So, maybe the battery hack? Just connect two wires to each pair of batteries? Just for testing the console temp.

                          Comment

                          • vinceroger69
                            Badcaps Legend
                            • Mar 2012
                            • 6714
                            • uk

                            #14
                            Re: Center Pin Polarity Check?

                            for testing joining the batteries will work but if soldering wires on watch the heat as batteries can explode.

                            Comment

                            • budm
                              Badcaps Legend
                              • Feb 2010
                              • 40746
                              • USA

                              #15
                              Re: Center Pin Polarity Check?

                              Originally posted by vestaviascott
                              Frick! I didn't catch that! So, maybe the battery hack? Just connect two wires to each pair of batteries? Just for testing the console temp.
                              You can solder wire to each pair of batteries and try.
                              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

                              • vestaviascott
                                Senior Member
                                • Aug 2018
                                • 100
                                • United States

                                #16
                                Re: Center Pin Polarity Check?

                                Originally posted by budm
                                That is correct. It is only rated at 1.3A (1300mA) @ 3 ~ 12V! as printed on the package.
                                2.1A for USB.
                                So, if the machine specifies 6v 2a and I try to use a 6v 1.3a power supply (aka the "universal" adapter above), it may or may not work or it definitely will not work?

                                Comment

                                • vestaviascott
                                  Senior Member
                                  • Aug 2018
                                  • 100
                                  • United States

                                  #17
                                  Re: Center Pin Polarity Check?

                                  Originally posted by budm
                                  You can solder wire to each pair of batteries and try.
                                  I may just tape the wires to the batteries. Its just to confirm the panel is working or not at this point before I invest in a proper matched power adapter and battery cover.

                                  Comment

                                  • mariushm
                                    Badcaps Legend
                                    • May 2011
                                    • 3799

                                    #18
                                    Re: Center Pin Polarity Check?

                                    The polarity is usually printed on the label or engraved in the plastic near the dc jack

                                    you should see a logo similar to this near the connector:



                                    majority of connectors these days have the negative on the outside and positive in the center. In older machines, sometimes the positive was on the outside because this was made it easier to disconnect internal batteries when the adapter was plugged in ...

                                    in your particular case, I'm not sure that universal adapter would be suitable. The thing uses D batteries, which are designed to be able to output a significant amount of current, more than what regular AA batteries can provide. So either the machine used D batteries for very long life (unlikely) or the machine really does require that 2A of current (or gets close to that ammount)
                                    So your 1.3A max adapter may not be enough to run the machine properly - at some points, if the machine pulls more than 1.3A , the adapter may reset or turn itself off, or the voltage could drop below some threshold.

                                    On the other hand, you have 4 D batteries, and this means the product has to account for batteries going low... new batteries would be 1.5v..1.65v for alkaline batteries while empty batteries would probably go down to around 1.35v..1.4v ... so the product may actually work with around 4 x 1.3v.. 1.35v = 5.2v .. 5.5v

                                    if your choice isn't good enough, you should test with a usb charger designed for max 2a, it may be able to power your machine even if the voltage is less than 6v
                                    Attached Files

                                    Comment

                                    • vestaviascott
                                      Senior Member
                                      • Aug 2018
                                      • 100
                                      • United States

                                      #19
                                      Re: Center Pin Polarity Check?

                                      Originally posted by mariushm
                                      The polarity is usually printed on the label or engraved in the plastic near the dc jack

                                      you should see a logo similar to this near the connector:

                                      That would certainly make it brain dead simple, but there is no such diagram to be found. That's why I'm asking how to test the polarity without that diagram to guide me.


                                      Originally posted by mariushm
                                      if your choice isn't good enough, you should test with a usb charger designed for max 2a, it may be able to power your machine even if the voltage is less than 6v
                                      The machine has a barrel type connector. How would I connect a USB charger to it?

                                      Comment

                                      • budm
                                        Badcaps Legend
                                        • Feb 2010
                                        • 40746
                                        • USA

                                        #20
                                        Re: Center Pin Polarity Check?

                                        Why don't you just try with batteries first just to see the if the machine is even working instead of discussing on how to use your universal power supply to power up this bike.
                                        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

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