1966 Corvette: Service Bulletin: Audible Noise in Radio - Chevrolet with Transistorized Ignition

Source: Chevrolet Technical Service Bulletin
Subject: Audible Noise in Radio - Chevrolet with Transistorized Ignition
Model and Year: All Chevrolets
Bulletin Number:  TSB #66-83
Section: VIy
Date: August 8, 1966

TO: ALL CHEVROLET SERVICE PERSONNEL

Engine noise may be audible in the radio of some Chevrolets equipped with factory installed transistor ignition.  The noise is caused by the additional ignition primary feed wire required by the transistor ignition system.  This wire runs from the ignition switch up and through the firewall, and attaches to a white resistance wire connecting to the transistor amplifier in the engine compartment.

Rerouting this wire, as follows, will correct audible engine noise in the radio:

1. Disconnect wire at white resistance wire and pull it into passenger compartment.
2. Route wire down left side of mast jacket (tape in two places) through the firewall and back up to the connector at the white resistance wire.
3. If noise is still present after rerouting wire, add a .3MFD capacitor to the positive terminal of the ignition coil.

NOTE:  DO NOT GO OVER .3MFD capacitor or the ignition system will be adversely affected.