1965 - 1972 Corvette: Service Bulletin: Moisture Entering Pulse Amplifier - Transistor Ignition Systems

Subject:   Moisture Entering Pulse Amplifier - Transistor Ignition Systems
Model and Year:   1965 - 1972 Corvette
Source:  Chevrolet Dealer Service Technical Service Bulletin
Bulletin No:  68-T-8
Section:   VIy
Date:  Dec. 19, 1967

TO:  ALL CHEVROLET DEALERS

The most common cause of transistor ignition pulse amplifier failure is moisture entry into the amplifier past the back cover seal or the connector coupling area.  Moist air can be drawn past minute gaps in these seal areas as a hot amplifier cools and creates an internal vacuum.  Over a period of many suck heat and cool cycles, enough moisture may enter to cause circuitry problems and render the ignition system inoperative.

A wider cover seal has been used in 1967 production amplifiers, and effective with November production, a non-conductive silicone grease is being used to pack the harness connector cavity approximately one-half full and effectively seal this area.

It is recommended that the harness connector be packed one-half full with Dow Corning Silicone Grease (or its equivalent available locally) whenever a transistor ignition equipped vehicle is being serviced.  If transistor ignition amplifier moisture problems are encountered, the unit should be serviced as outlined on page 1 of the November, 1966, Service News and the harness connector should be packed.