Kenwood TS-930S Circuit Diagram

Discussion in 'Radio Circuits, Repair & Performance' started by G3YRO, Nov 6, 2019.

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  1. G3YRO

    G3YRO Ham Member QRZ Page

    Does anyone have a copy of the Diagram showing all the Board Interconnections for the TS930 ?

    I want to look at doing a mod to bypass the CW Bandwidth control when switched to Narrow . . . but the only copy of the interconnection diagram I have is illegible !

    (I already have downloads of all the Manuals and other diagrams . . . but not the one that shows all the external connections to all the Pots and Switches)

    Hope someone can help

    Roger G3YRO
  2. KA5IPF

    KA5IPF Ham Member QRZ Page

    Pictures on the way.
  3. G3YRO

    G3YRO Ham Member QRZ Page

    Really appreciate your help sending those Clif

    Many thanks ! (have replied to your e-mail)

    If I can sort out a Mod that works OK I shall post it on here.

    Roger G3YRO
  4. N8YX

    N8YX Ham Member QRZ Page

    I did something similar to control a roofing-filter switch: There are two sections on the Wide/Narrow that routes voltage to the CW filters and another which does same for the accessory AM filter (if installed).

    My homebrew "AM" roofing filter is inline on AM RX with the switch set to "Wide". Otherwise, the Inrad SSB roofing filter (which has a considerably narrower passband) is in the circuit.

    Study the switch circuit and you're halfway there. I'll poke through my documentation and see if I can see a clean way to do what you're attempting.
  5. G3YRO

    G3YRO Ham Member QRZ Page

    Yes, I'm thinking just a miniature relay to connect to fixed Resistors instead of the Pot in the Narrow CW Position . . . it's whether the switch can power the relay direct, or whether I need a transistor to switch it.

    And of course finding the easiest place to pick up the Narrow switch voltage, without having to start removing any panels or boards.

    But I haven't started studying the circuit yet, so any help would be appreciated !

    Roger G3YRO
  6. G3YRO

    G3YRO Ham Member QRZ Page

    Just been looking at the CW Variable Bandwidth pot diagram . . . of course it's very simple . . .

    All I need to do is take the lead that comes from the base of Q3 to the common pole on a relay . . . and connect the N/C pole to the wiper and the N/O to the clockwise end of the pot . . . simple ! So will obviously just mount the relay near the pot.

    Just need to suss out picking up the Narrow Control voltage easily.

    Roger G3YRO
    Last edited: Nov 7, 2019
  7. G3YRO

    G3YRO Ham Member QRZ Page

    I can see that the control signal for CW Narrow ends up on Pin 3 of J12 on the Signal Board . . . so I could pick it up there.

    But it's quite hard to follow where the line comes from that goes through the switch.

    Do you recall John, is this just a low resistance positive Voltage?

    Roger G3YRO
  8. N8YX

    N8YX Ham Member QRZ Page

    Yes. 15v, IIRC. If you're familiar with the small 12v Omron SPDT relays on the Signal Board, I used the voltage from that switch connection through a 150 ohm resistor to drive a bank of them directly in my filter switch setup. Should your Junque Box be as well stocked with Kenwood parts as mine, you're 90% there.
  9. KA5IPF

    KA5IPF Ham Member QRZ Page

    Just remember while you are re-engineering the circuit that the narrow filters are only used in RX
    KA9JLM likes this.

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