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How to Adjust a Vibroplex Iambic Key

Vibroplex telegraphic keys were invented at the beginning of the 20th century to satisfy the needs of high-volume, proficient telegraph operators. Vibroplex continues to produce telegraph keys, and you can connect a Vibroplex key to a to ham-radio transceiver and use it to transmit Morse code signals over the radio waves. Among the full range of keys that Vibroplex offers are four versions of its flagship Iambic, or dual-key, model. This model uses one key to send dots and the other dashes. You can easily make adjustments to a Vibroplex Iambic key by tightening and loosening screws.

Things You'll Need

Small screwdriver

Instructions

- 1
  Disconnect your Standard, Deluxe, Presentation or Gold Iambic Paddle from its transceiver connection cord and turn the paddle upside down.
- 2
  Loosen the small set screws that are located on the bottom of the mainframe under the paddle brackets.
- 3
  Turn each of the lower trunion screws, which are the long screws located in between the set screws, in either direction until the lever moves freely from side to side, without any up and down movement.
- 4
  Tighten the set screws and turn the key right side up.
- 5
  Loosen the contact slide screw at the end of each of the two keys (farthest away from the handle). Move the contact slide (the small oval piece of metal with an oval hole inside) toward or away from the handle as necessary so that it lines up with the contact post contact under it.
- 6
  Tighten the contact slide screw again once you have the slide in the right position.
- 7
  Increase or decrease the tension in the keys by tightening or loosening each of the two tension screws that hold the keys in at the side of the mainframe. Make the adjustments in small increments. Try the keys between adjustments so that you can stop adjusting when you are comfortable with the amount of tension in each key.
- 8
  Connect your paddle to the cable and the cable to your transceiver to test the adjustments. Repeat any steps if you are not comfortable with the new settings.

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