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Re: [CDV700CLUB] Stop that whining!

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  • Phil Bigelow
    Thanky, dinky, spanky-doo for the tip, Geo! -- On Mon, 1 May 2006 14:05:55 -0500 GEOelectronics ... -- We recognize, however dimly, that greater
    Message 1 of 2 , May 1, 2006
      Thanky, dinky, spanky-doo for the tip, Geo!

      <pb>
      --

      On Mon, 1 May 2006 14:05:55 -0500 "GEOelectronics"
      <GEOelectronics@...> writes:
      > Whining in the earphone, CDV-700 by ENi, often a problem. Several
      > causes have been located and documented ( bad electrolytic filter,
      > bad transistors, bad diode) but a new one was found today.
      >
      > During the production run of the '700, ENi switched transformers.
      > Now I know why. The transformer without the brass grounding strap
      > can cause whining in the electronics, including the pinned meter
      > syndrome. Wiggling things around might stop it, but it always comes
      > back.
      >
      > Fortunately the non-grounded transformer has a metal frame which is
      > easily soldered to. Use a brass or copper strip, 1/4" wide to solder
      > to the frame and then to the ground trace on the circuit board,
      > immediately adjacent to the grounding screw. A wire MIGHT work, but
      > a low impedance strip is better.
      >
      >


      --
      "We recognize, however dimly, that greater efficiency, ease, and security
      may come at a substantial price in freedom, that law and order can be a
      doublethink version of oppression, that individual liberties surrendered,
      for whatever good reason, are freedoms lost." - Walter Cronkite, preface
      to the 1984 edition of George Orwell's _1984_.
    • GEOelectronics
      Whining in the earphone, CDV-700 by ENi, often a problem. Several causes have been located and documented ( bad electrolytic filter, bad transistors, bad
      Message 2 of 2 , May 1, 2006
        Whining in the earphone, CDV-700 by ENi, often a problem. Several causes have been located and documented ( bad electrolytic filter, bad transistors, bad diode) but a new one was found today.
         
        During the production run of the '700, ENi switched transformers. Now I know why. The transformer without the brass grounding strap can cause whining in the electronics, including the pinned meter syndrome. Wiggling things around might stop it, but it always comes back.
         
        Fortunately the non-grounded transformer has a metal frame which is easily soldered to. Use a brass or copper strip, 1/4" wide to solder to the frame and then to the ground trace on the circuit board, immediately adjacent to the grounding screw. A wire MIGHT work, but a low impedance strip is better.
         
        Geo
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