Summary

A guide to adjusting a Vibroplex Bug, plus resources for identification and dating.

Adjustment Procedure

1. Basic Checks: Begin the procedure by ensuring the arm moves freely, contact posts are tight, and dot and dash contacts are properly aligned and clean.
2. Initial Settings: Make initial adjustments by setting the lever rest position and defining the initial lever dot travel (e.g., a 0.015 inch gap between the Left Stop Screw and the lever for the Original model) using the stop screws.
3. Travel & Tension: Adjust the initial dash travel to match the dot travel, set the initial dot contact position so the contacts are just closed when oscillation stops, and set initial dash and dot spring tension.
4. Fine Tuning: Proceed to fine adjustments, ideally using an analog Ohm meter to check continuity. Adjust the Dot Contact Screw until the meter reads 50% of full scale during dot oscillation, confirming a 1:1 dot:space ratio.
5. Damping: Adjust the Dot Tension Screw until the arm returns quickly to the damper wheel and stops completely without bouncing. This is critical for preventing scratchy dots.
6. Final Checkout: Connect the bug to a practice oscillator for a final checkout, ensuring that the dots and dashes are clean across the entire operational speed range.

Identification & Dating Guides

Dating by Serial Number With original factory records lost, access John Elwood’s (WW7P) essential guide to dating your key, reconstructed from over 3,000 serial numbers: WW7P Vibroplex Dating Guide

Model Identification Which Vibroplex do you own? Explore the differences between the current “Original” and the many variations of the past: Vibroplex Collector Guide

Comprehensive Lookup Putting it all together: A unified method based on the data above: Date & Model Lookup