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Re: [softrock40] Ensemble RXTX Power supply problem

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  • Alan
    ... Subject: [softrock40] Ensemble RXTX Power supply problem ... Jon, to expand:- This sort of test is very rough, gives some idea but the meter you use will
    Message 1 of 10 , Jul 4, 2013
      ----- Original Message -----
      Subject: [softrock40] Ensemble RXTX Power supply problem


      >
      > The first test is the resistance test where you
      > measure the resistance across the non-hairpin end of
      > R52 and ground. It's supposed to start around 50k and then
      > go to infinite as the caps charge up.
      > Mine goes from 2k to infinite.
      >

      Jon, to expand:-

      This sort of test is very rough, gives some idea but the meter you use will affect actual readings seen. Yours does what would be
      expected. The test is just to make sure there is no short to ground.

      > The second test is to measure the current draw
      > of the circuit. I was a little confused by the instructions
      > on this. One page says to just put your UOM in series with
      > the test power supply (a 12v battery in my case) and the board
      > but the next page shows a "limiting" resistor in the series as
      > well but I didn't use one. The current draw is supposed
      > to be <8 mA and mine is 11.7 mA
      >

      Yes, this is higher than normally expected.
      As Chris says a current limit can prevent destruction.

      > The third test is to check the voltage on the powered up
      > board at two points.
      >
      > 1. The voltage between the hairpin end
      > of D4 and ground (supposed to be 12V and mine was 12V).
      >
      > 2.The voltage between the hairpin hole for R61 and ground.
      > This is supposed to be around 5V and mine is 9.9V.
      >
      > I've double checked all the parts to make sure their polarities
      > are correct and the correct "hairpin" mounts are all in the
      > right holes.
      >
      > Does anyone have any suggestions on how to proceed?
      >
      > Is there a way to test U9, the voltage regulator?
      > The 5V is supposed to come out of it.
      >

      What is the voltage at the input of the regulator?
      If it more than 8V then there should be 5V on the output. (Assuming all capacitors are fitted and that all pins are correctly
      soldered and the centre pin is grounded)
      If the input and output is at the same voltage the regulator is faulty unless there is a physical short between them.
      Very occasionally a whisker of copper has been left somewhere after manufacture.

      73 Alan G4ZFQ
    • Angi Harrover
      I was wanting to know where to find one. I love to build kits don t have allot money to buy one but would like to build for others. I have built countless kits
      Message 2 of 10 , Jul 5, 2013
        I was wanting to know where to find one. I love to build kits don't have allot money to buy one but would like to build for others. I have built countless kits and want to build one for my self just money is real tight. Anyone know where I can pick one up?
         


      • KENNETH CHASE
        http://fivedash.com/   Ken VA3ABN From: Angi Harrover To: softrock40@yahoogroups.com Sent: Friday,
        Message 3 of 10 , Jul 5, 2013
           
          Ken VA3ABN

          From: Angi Harrover <angiharrover@...>
          To: "softrock40@yahoogroups.com" <softrock40@yahoogroups.com>
          Sent: Friday, July 5, 2013 11:03:07 AM
          Subject: [softrock40] Where can I get a soft rock kit?
           
          I was wanting to know where to find one. I love to build kits don't have allot money to buy one but would like to build for others. I have built countless kits and want to build one for my self just money is real tight. Anyone know where I can pick one up?
           

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