Tenma 72-10495 (Korad 3005D-2S) excessive current display beyond limit

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  • japlytic
    Badcaps Legend
    • Oct 2005
    • 2086
    • Australia

    #1

    Tenma 72-10495 (Korad 3005D-2S) excessive current display beyond limit

    When I was trying to use this power supply as split rails of different voltages, I got a current draw reading of about 6.7A on the left channel (way above its preset limit - both channels can be set up to 5.1A), despite removing the output leads from its banana sockets and earlier on, the left fan was running unusually fast for its settings.
    Carefully grounding the inputs of the TL082 op-amps revealed a drop in the current reading (I suspected the op-amps or the microcontroller was faulty ); an accidental push on the op-amps caused the current display to drop to zero, so the (original) TL082 op-amps on this board along with the op-amps on the other identical channel were reworked and this problem was fixed .

    Note that in Independent Mode, both rails are completely isolated from each other, and in all cases, the communication lines between the microcontrollers on each channel are isolated via optocouplers.
    My first choice in quality Japanese electrolytics is Nippon Chemi-Con, which has been in business since 1931... the quality of electronics is dependent on the quality of the electrolytics.
  • stj
    Great Sage 齊天大聖
    • Dec 2009
    • 31015
    • Albion

    #2
    Re: Tenma 72-10495 (Korad 3005D-2S) excessive current display beyond limit

    so what your saying is the soldering is as bad as the soldering stations!

    Comment

    • ben7
      Capaholic
      • Jan 2011
      • 4059
      • USA

      #3
      Re: Tenma 72-10495 (Korad 3005D-2S) excessive current display beyond limit

      Are the op-amps in a socket?
      I have this Yihua PSU that had the op-amps in sockets!
      WORST OF ALL, the socket contacts were GREEN from corrosion .... failure waiting to happen! I took them out lol.
      Don't want my circuits fried...
      And, that main filter cap which is 50V rated, gets about 55 to 60V on it when the output is set all the way up ... hasn't bulged at all, I think it isn't enough of an over-voltage to cause it to fail.
      Last edited by ben7; 03-31-2015, 06:53 AM.
      Muh-soggy-knee

      Comment

      • stj
        Great Sage 齊天大聖
        • Dec 2009
        • 31015
        • Albion

        #4
        Re: Tenma 72-10495 (Korad 3005D-2S) excessive current display beyond limit

        ooo - nice avatar!

        Comment

        • ben7
          Capaholic
          • Jan 2011
          • 4059
          • USA

          #5
          Re: Tenma 72-10495 (Korad 3005D-2S) excessive current display beyond limit

          Originally posted by stj
          ooo - nice avatar!
          Hm?, Me?
          Muh-soggy-knee

          Comment

          • stj
            Great Sage 齊天大聖
            • Dec 2009
            • 31015
            • Albion

            #6
            Re: Tenma 72-10495 (Korad 3005D-2S) excessive current display beyond limit

            yes

            Comment

            • japlytic
              Badcaps Legend
              • Oct 2005
              • 2086
              • Australia

              #7
              Re: Tenma 72-10495 (Korad 3005D-2S) excessive current display beyond limit

              Originally posted by ben7
              Are the op-amps in a socket?
              All of the op-amps are surface mounted.
              My first choice in quality Japanese electrolytics is Nippon Chemi-Con, which has been in business since 1931... the quality of electronics is dependent on the quality of the electrolytics.

              Comment

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