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SoftRock Lite II power supply question

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  • wardwebber
    I m new to kit building, and I have a question on what kind of power supply I should use to test the Power Supply section of the SoftRock Lite II kit. W5BRVZ s
    Message 1 of 7 , Mar 23, 2013
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      I'm new to kit building, and I have a question on what kind of power supply I should use to test the Power Supply section of the SoftRock Lite II kit.

      W5BRVZ's otherwise excellent instructions say to use a 12-volt source, but they don't specify the amps. So I bought a little 12V battery at a drugstore and used that (Duracell MN21/A23). At the 5 Vdc test point I'm getting 5.04 volts, so that's okay.

      When I test the milliamps test points, my multimeter shows about 00.78 mA initially, and then continuously descends (it should be 3-6 mA). I get the same result if I just test the battery itself, so my soldering doesn't appear to be the cause. (For the test points I'm using the + and - contacts where the power source connects to the board; is this wrong?)

      Any ideas why the mAs descend? And why they're so low? Should I use a different kind of 12-V battery, or buy a proper 12-V power supply to boost the mA? If so, how many mA should it be set to, to make this test?
    • John Greusel
      Ward, I might be misunderstanding but for current measurements you have to put the amp meter directing in the current path. It has to interrupt either the
      Message 2 of 7 , Mar 23, 2013
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        Ward,

        I might be misunderstanding but for current measurements you have to put the amp meter directing in the current path.
        It has to interrupt either the positive or negative line as part of the circuit. + power supply to red amp meter line then black amp meter to + connection at radio.

        John
        KC9OJV
         



        From: wardwebber <wardwebber@...>
        To: softrock40@yahoogroups.com
        Sent: Saturday, March 23, 2013 11:22 AM
        Subject: [softrock40] SoftRock Lite II power supply question

         
        I'm new to kit building, and I have a question on what kind of power supply I should use to test the Power Supply section of the SoftRock Lite II kit.

        W5BRVZ's otherwise excellent instructions say to use a 12-volt source, but they don't specify the amps. So I bought a little 12V battery at a drugstore and used that (Duracell MN21/A23). At the 5 Vdc test point I'm getting 5.04 volts, so that's okay.

        When I test the milliamps test points, my multimeter shows about 00.78 mA initially, and then continuously descends (it should be 3-6 mA). I get the same result if I just test the battery itself, so my soldering doesn't appear to be the cause. (For the test points I'm using the + and - contacts where the power source connects to the board; is this wrong?)

        Any ideas why the mAs descend? And why they're so low? Should I use a different kind of 12-V battery, or buy a proper 12-V power supply to boost the mA? If so, how many mA should it be set to, to make this test?



      • Alan
        ... Subject: [softrock40] SoftRock Lite II power supply question ... I think this is a little too small. For a Lite one of the small 9V packs would be good for
        Message 3 of 7 , Mar 23, 2013
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          ----- Original Message -----
          Subject: [softrock40] SoftRock Lite II power supply question


          > I'm new to kit building, and I have a question on what kind of power supply I should use to test the Power Supply section of the
          > SoftRock Lite II kit.
          >
          > W5BRVZ's otherwise excellent instructions say to use a 12-volt source, but they don't specify the amps. So I bought a little 12V
          > battery at a drugstore and used that (Duracell MN21/A23). At the 5 Vdc test point I'm getting 5.04 volts, so that's okay.
          >
          > When I test the milliamps test points, my multimeter shows about 00.78 mA initially, and then continuously descends (it should be
          > 3-6 mA). I get the same result if I just test the battery itself, so my soldering doesn't appear to be the cause. (For the test
          > points I'm using the + and - contacts where the power source connects to the board; is this wrong?)
          >
          > Any ideas why the mAs descend? And why they're so low? Should I use a different kind of 12-V battery, or buy a proper 12-V power
          > supply to boost the mA? If so, how many mA should it be set to, to make this test?
          >

          I think this is a little too small.
          For a Lite one of the small 9V packs would be good for a few hours of use. You do not actually need more voltage than that.
          But as long as you get 5V that is all you need. The current may drop a little from startup when the capacitors charge, the small
          battery might make this more obvious.
          And, as John says, are you testing the current correctly? Meter + to + on the battery. Meter - to + input on Softrock.

          73 Alan G4ZFQ
        • wardwebber
          Thanks for your replies, John and Alan. I tried connecting the multimeter s pos. terminal to the battery pos. terminal, the multimeter neg. to the pos. input
          Message 4 of 7 , Mar 23, 2013
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            Thanks for your replies, John and Alan. I tried connecting the multimeter's pos. terminal to the battery pos. terminal, the multimeter neg. to the pos. input on the board, and the battery neg. to the neg. input on the board. I got a steady 2.13 mA--better than the previous result, but less than the nominal 3-6 mA.

            So either my tester's not very accurate (it's only a $35 one, although it's new), my soldering's not good, or I need a power source that can produce a stronger current. Will a standard 9-V battery do that, or would that exceed the specified 5-V power input and invalidate my tests?


            --- In softrock40@yahoogroups.com, "Alan" <alan4alan@...> wrote:
            >
            >
            > ----- Original Message -----
            > Subject: [softrock40] SoftRock Lite II power supply question
            >
            >
            > > I'm new to kit building, and I have a question on what kind of power supply I should use to test the Power Supply section of the
            > > SoftRock Lite II kit.
            > >
            > > W5BRVZ's otherwise excellent instructions say to use a 12-volt source, but they don't specify the amps. So I bought a little 12V
            > > battery at a drugstore and used that (Duracell MN21/A23). At the 5 Vdc test point I'm getting 5.04 volts, so that's okay.
            > >
            > > When I test the milliamps test points, my multimeter shows about 00.78 mA initially, and then continuously descends (it should be
            > > 3-6 mA). I get the same result if I just test the battery itself, so my soldering doesn't appear to be the cause. (For the test
            > > points I'm using the + and - contacts where the power source connects to the board; is this wrong?)
            > >
            > > Any ideas why the mAs descend? And why they're so low? Should I use a different kind of 12-V battery, or buy a proper 12-V power
            > > supply to boost the mA? If so, how many mA should it be set to, to make this test?
            > >
            >
            > I think this is a little too small.
            > For a Lite one of the small 9V packs would be good for a few hours of use. You do not actually need more voltage than that.
            > But as long as you get 5V that is all you need. The current may drop a little from startup when the capacitors charge, the small
            > battery might make this more obvious.
            > And, as John says, are you testing the current correctly? Meter + to + on the battery. Meter - to + input on Softrock.
            >
            > 73 Alan G4ZFQ
            >
          • cc_photo
            This new current measurement may be OK .. I think the stated current range was likely measured using a 12-14vdc power supply, not a 9v supply, which would
            Message 5 of 7 , Mar 24, 2013
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              This new current measurement may be OK .. I think the stated current range was likely measured using a 12-14vdc power supply, not a 9v supply, which would yield the slightly higher stated range of current.
              Roland, KB8XI


              --- In softrock40@yahoogroups.com, "wardwebber" <wardwebber@...> wrote:
              >
              > Thanks for your replies, John and Alan. I tried connecting the multimeter's pos. terminal to the battery pos. terminal, the multimeter neg. to the pos. input on the board, and the battery neg. to the neg. input on the board. I got a steady 2.13 mA--better than the previous result, but less than the nominal 3-6 mA.
              >
              > So either my tester's not very accurate (it's only a $35 one, although it's new), my soldering's not good, or I need a power source that can produce a stronger current. Will a standard 9-V battery do that, or would that exceed the specified 5-V power input and invalidate my tests?
              >
              >
              > --- In softrock40@yahoogroups.com, "Alan" <alan4alan@> wrote:
              > >
              > >
              > > ----- Original Message -----
              > > Subject: [softrock40] SoftRock Lite II power supply question
              > >
              > >
              > > > I'm new to kit building, and I have a question on what kind of power supply I should use to test the Power Supply section of the
              > > > SoftRock Lite II kit.
              > > >
              > > > W5BRVZ's otherwise excellent instructions say to use a 12-volt source, but they don't specify the amps. So I bought a little 12V
              > > > battery at a drugstore and used that (Duracell MN21/A23). At the 5 Vdc test point I'm getting 5.04 volts, so that's okay.
              > > >
              > > > When I test the milliamps test points, my multimeter shows about 00.78 mA initially, and then continuously descends (it should be
              > > > 3-6 mA). I get the same result if I just test the battery itself, so my soldering doesn't appear to be the cause. (For the test
              > > > points I'm using the + and - contacts where the power source connects to the board; is this wrong?)
              > > >
              > > > Any ideas why the mAs descend? And why they're so low? Should I use a different kind of 12-V battery, or buy a proper 12-V power
              > > > supply to boost the mA? If so, how many mA should it be set to, to make this test?
              > > >
              > >
              > > I think this is a little too small.
              > > For a Lite one of the small 9V packs would be good for a few hours of use. You do not actually need more voltage than that.
              > > But as long as you get 5V that is all you need. The current may drop a little from startup when the capacitors charge, the small
              > > battery might make this more obvious.
              > > And, as John says, are you testing the current correctly? Meter + to + on the battery. Meter - to + input on Softrock.
              > >
              > > 73 Alan G4ZFQ
              > >
              >
            • Douglas Lash
              When I need a low current inexpensive 9V or 5V supply I go to one of the many local thrift shops and search through the cell phone and printer chargers. There
              Message 6 of 7 , Mar 24, 2013
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                When I need a low current inexpensive 9V or 5V supply I go to one of
                the many local thrift shops and search through the cell phone and
                printer chargers. There is usually something that will work for
                $2-$5.
                73,
                Doug (AG6EG) Lash
              • wardwebber
                Thanks, Roland; I ll proceed with the testing, accepting the 2.13 mA result. If I have trouble later, I ll post a whine about it ;-)
                Message 7 of 7 , Apr 2, 2013
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                  Thanks, Roland; I'll proceed with the testing, accepting the 2.13 mA result. If I have trouble later, I'll post a whine about it ;-)

                  --- In softrock40@yahoogroups.com, "cc_photo" <kb8xi@...> wrote:
                  >
                  >
                  >
                  >
                  > This new current measurement may be OK .. I think the stated current range was likely measured using a 12-14vdc power supply, not a 9v supply, which would yield the slightly higher stated range of current.
                  > Roland, KB8XI
                  >
                  >
                  > --- In softrock40@yahoogroups.com, "wardwebber" <wardwebber@> wrote:
                  > >
                  > > Thanks for your replies, John and Alan. I tried connecting the multimeter's pos. terminal to the battery pos. terminal, the multimeter neg. to the pos. input on the board, and the battery neg. to the neg. input on the board. I got a steady 2.13 mA--better than the previous result, but less than the nominal 3-6 mA.
                  > >
                  > > So either my tester's not very accurate (it's only a $35 one, although it's new), my soldering's not good, or I need a power source that can produce a stronger current. Will a standard 9-V battery do that, or would that exceed the specified 5-V power input and invalidate my tests?
                  > >
                  > >
                  > > --- In softrock40@yahoogroups.com, "Alan" <alan4alan@> wrote:
                  > > >
                  > > >
                  > > > ----- Original Message -----
                  > > > Subject: [softrock40] SoftRock Lite II power supply question
                  > > >
                  > > >
                  > > > > I'm new to kit building, and I have a question on what kind of power supply I should use to test the Power Supply section of the
                  > > > > SoftRock Lite II kit.
                  > > > >
                  > > > > W5BRVZ's otherwise excellent instructions say to use a 12-volt source, but they don't specify the amps. So I bought a little 12V
                  > > > > battery at a drugstore and used that (Duracell MN21/A23). At the 5 Vdc test point I'm getting 5.04 volts, so that's okay.
                  > > > >
                  > > > > When I test the milliamps test points, my multimeter shows about 00.78 mA initially, and then continuously descends (it should be
                  > > > > 3-6 mA). I get the same result if I just test the battery itself, so my soldering doesn't appear to be the cause. (For the test
                  > > > > points I'm using the + and - contacts where the power source connects to the board; is this wrong?)
                  > > > >
                  > > > > Any ideas why the mAs descend? And why they're so low? Should I use a different kind of 12-V battery, or buy a proper 12-V power
                  > > > > supply to boost the mA? If so, how many mA should it be set to, to make this test?
                  > > > >
                  > > >
                  > > > I think this is a little too small.
                  > > > For a Lite one of the small 9V packs would be good for a few hours of use. You do not actually need more voltage than that.
                  > > > But as long as you get 5V that is all you need. The current may drop a little from startup when the capacitors charge, the small
                  > > > battery might make this more obvious.
                  > > > And, as John says, are you testing the current correctly? Meter + to + on the battery. Meter - to + input on Softrock.
                  > > >
                  > > > 73 Alan G4ZFQ
                  > > >
                  > >
                  >
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