Kenwood TS-50 please help

Discussion in 'Radio Circuits, Repair & Performance' started by AE5SB, Sep 14, 2019.

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  1. K7TRF

    K7TRF Premium Subscriber QRZ Page

    Gut feel without diving into the TS-50 schematic is that you somehow lifted the ground trace to the volume pot. IOW, it's acting as a series rheostat as opposed to a potentiometer wired as a voltage divider. If that's true you'll get some volume control as the series resistance between the top of the pot and the wiper is increased but you won't be able to bring the volume all the way down to zero if the ground side is floating. You should be able to validate whether that's happening with an ohm meter between the pot's wiper and ground and watching what happens to that resistance as you vary the pot's position. If there's an open between the bottom of the pot and ground it could be internal to the pot if for instance there was excessive heat while soldering in the new part or it could be external to the pot as in a broken trace or bad solder joint.

    Also, are you certain you replaced the pot with the appropriate taper? It's most likely an audio taper pot (log taper) in this application and using a linear taper pot would cause some interesting volume control problems.
  2. AE5SB

    AE5SB Ham Member QRZ Page

    Hello David and thanks for your reply
    I replaced the pot with a factory item from PAC Parts for $22+ I might add
    I think you are right with the ground idea and as it had this problem when I received it (before replacing pot)
    in a couple of days its going back on the bench
    wish me luck
  3. AE5SB

    AE5SB Ham Member QRZ Page

    Hey Guy's
    It's fixed!!!
    David you were right there was no ground at the audio pot
    the trace from the pot to the plug had a tiny crack
    most likely happened when the original pot got the shaft bent
    anyway, patched the trace and all is working great.
    Its always something simple!
    Thank You to everyone - You guys are great
    73 from David AE5SB
    N8VIL, K7TRF and W1TRY like this.
  4. W1TRY

    W1TRY XML Subscriber QRZ Page

    Thanks for the update, David, and congratulations on a job well done.

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