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Thread: Kenwood TS480SAT Receive Audio Low Amplitude Output. ( Intermittent ) Fault

  1. #1

    Default Kenwood TS480SAT Receive Audio Low Amplitude Output. ( Intermittent ) Fault

    Kenwood models : TS480SAT and TS480HX Transceiver .

    Receive Output Audio will lessen to a whisper once unit is powered on for a few minutes.
    Unit may Power On initially with the Receive Output Audio at a very very low level, as well.

    Within the TX-RX Circuit Board -
    The circuit net which Fails is the + 3.32 v DC Supply Voltage which is sourced by IC215 and sinked to several of the Receive Audio Circuit including : DSP - IC 220, CODEC - IC217, FILTER AMP - IC214, ANTI-ALIASING FILTER - IC218, ANALOG SWITCH - IC219, MICROPHONE AMP - IC221, A/D Convertor - IC212, BUFFER IC - IC209, MCU - IC204, MULTIPLEXER - IC201, INVERTER - IC223 and BUFFER - IC222.

    Within the TX-RX Circuit Board Capacitor designation C281 has failed, possibly due to heat generated under a Metallic Shielding Can (which primary purpose is to enclose and protect the DSP ( digital signal processor ) IC220 ( 144 pin FPGA ) component and the MCU ( Main Microcomputer ) IC204 (144 pin FPGA )). C281 is a 100 uF 6.3v electrolytic capacitor in a SMT package.
    This Electrolytic Capacitor ( C281 ) can see very high temperatures, due to its physical location in the far rear left corner ( as viewed from the Top Front of the Base Unit). This tightly enclosed corner location is a concentrated heat area under the above mentioned Shielding Can. Electrolytic Capacitor's over extended period of time seeing higher temperatures may cause the dielectric material to become of liquid state and leak out of the capacitor component can enclosure package.

    Pictures Included in next Reply.

    AJ4UY
    Last edited by AJ4UY; Fri 2nd Aug 2019 at 15:26. Reason: Picture ADD next reply.

  2. #2

    Post

    Pictures are to be added here.
    As a new member to this Forum Page, it appears that I have been given early membership permission with No Attachments allowed.
    This is what I understand. I may not know this Forum very well, at this time.

    I may have to find another means to Post Pictures To Support My Post Entries, here.

    Thank You.
    AJ4UY
    Last edited by AJ4UY; Fri 2nd Aug 2019 at 22:39.

  3. #3

    Default C281 Capacitor specs

    Still Want To Post Some Pictures.
    Meanwhile, I can post C281 specs related to temperature,
    summarized a leave link to it's Spec. C281 original manufacturer is Nichicon Series EU Electrolytic.

    tegory Temperature Range

    Endurance

    Shelf Life

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