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Thread: Kenwood TS-940S

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  1. #11
    Join Date
    Dec 2007
    Location
    Vancouver, BC CANADA
    Posts
    22

    Default

    Do you still have the '940? Are you willing to sell it?

  2. #12
    Join Date
    Nov 2008
    Location
    Toledo, Ohio in the United States of America
    Posts
    719

    Default

    The TS-940s is a great radio, but because of its age, they are starting to develop problems. I had to repair mine, soon after I purchased it, and I recently repaired another one that had a couple of bad caps.
    I have also saw battery leakage in a few of them too, so if you are going to service it, battery replacement would be a good idea.

    KZI, it is possible that a bad cap or something caused the failure of Q2, so check the circuit before just replacing the bad transistor.

    Laura, does the radio have modulation in the other modes (AM/FM)?
    If not, try another microphone first.

    As KX2E has indicated, there are many issues with those darn molex connectors, and bad solder connections galore.

    I love the TS-940S so much, I wrote some nice computer interface software last year, it's totally free, you can find out about it here:
    Of course you will need to have the Piexx interface board, or Kenwood's interface board to use it.
    Last edited by KA8RAW; 02-07-2010 at 08:28 AM. Reason: Provide link
    [SIZE=1]So you run and you run to catch up with the sun but it's sinking
    Racing around to come up behind you again.
    The sun is the same in a relative way but you're older,
    Shorter of breath and one day closer to death. [/SIZE]

  3. #13

    Default

    [QUOTE=KA8RAW;1853397]The TS-940s is a great radio, but because of its age, they are starting to develop problems. I had to repair mine, soon after I purchased it, and I recently repaired another one that had a couple of bad caps.
    I have also saw battery leakage in a few of them too, so if you are going to service it, battery replacement would be a good idea.

    I'm just fixing some problems like these, batteries, caps and the AVR to prevent the rig of future damages.
    The batteries are VARTA CR 1/2 AA 3V Lithium Made in Germany
    The exchange is easy to do. I can send You pics, if You mail me Your address to dj7kh@darc.de
    73, Hans

  4. #14
    Join Date
    Sep 2005
    Location
    I hope someplace in the Visayas
    Posts
    920

    Default

    Quote Originally Posted by G0GQK View Post
    Laura,

    Same suggestion for you, go to the Yahoo 940 group and they will be able to give you advice.

    Re my comment about being not helpful to someone in Scotland. Its no use giving people US information if they live 3,000 miles away !

    G0GQK


    However there are people in the US that might see the information so it is usefull to them, hence not a wasted post..

  5. #15
    Join Date
    Jul 2001
    Location
    NEWBERN, TN. 38059  EM56
    Posts
    25

    Default TS 940s power supply

    I am needing a power supply for the 940s board number is x43-1500-00. The serial number on this rig is 9090159. If you can help please email me . hireddux@yahoo.com Thanks in advance if ya can help. Howard
    HAVE 6M W.A.S. #1106,VUCC#1143,225GRIDS,#18 6 ON 6 AWARD. BOTH BORDERS WORKED#A109, ST. LAWRENCE SEAWAY AWARD#180.JUST FINISHED 6 M QRP W.A.S. & 2M VUCC, WORKING ON 222SSB and ON 432SSB.

  6. #16
    Join Date
    Feb 2005
    Location
    Barberton, Ohio
    Posts
    11,218

    Default

    To the OP:

    The symptoms you describe are typical of a PLL Board failure.

    It is located underneath the Digital A board's bottom shield; top side of the radio.

    Remove the Digital A and PLL boards; you'll need to disconnect the headers from the latter but can swing the former away without having to remove anything. You will find a ~1"x1" piece of black foam stuck to the foil side of the PLL board. Carefully remove all traces of the foam and resolder all of the connections which were covered by it. Then mount the PLL board and plug all of its harness connectors back into their receptacles. Lastly, check to see if the synthesizer will now lock. Adjustments may be required, and since the synthesizer is a 5-loop design a 100MHz 'scope and the service manual procedures MUST be utilized.

    This "foam failure" is somewhat common and is well documented on various TS-940 sites. The foam (a VCO microphonic damper) becomes hygroscopic as it ages and will cause oxidation of the underlying solder connections...leading to circuit failures.
    The AR15/M16 - Irritating practically everyone since 1960...

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