Audio - Inoperative Radio/Erratic Clock Display
Number 85-9-5 Date5/85
Subject: INOPERATIVE RADIO AND/OR ERRATIC CLOCK DISPLAY
1984 6000 STE AND 1985 PARISIENNE
Some early 1984 6000 STE and 1985 Parisienne models equipped with cassette tape decks may experience a condition of an inoperative radio and/or erratic clock display along with normal unaffected tape deck performance. This condition may be caused by an electrostatic discharge inside the receiver. Vehicles operated in areas of low humidity increase the possibility of this condition occurring. For this condition to occur, the tape unit must be in use and the tape search feature activated. If a sufficient static electricity charge is generated, it can discharge through the receiver microprocessor causing the radio and/or clock display to be inoperative. The tape deck operation does not depend on the microprocessor and will remain operational after this condition occurs. This temporary disablement of the receiver microprocessor can be reversed by removing all voltage from the radio receiver, however, the unit should be removed and sent to an authorized Delco Repair Shop for correction to prevent this condition from recurring.
To diagnose if an electrostatic discharge is the cause of the inoperative radio and/or erratic clock display, the following test should be used.
1 Verify that the AM and FM bands of the receiver do not operate
and that the cassette tape deck does operate correctly.
2. Remove power to the radio for a minimum of 10 seconds by either disconnecting and reconnecting the negative battery cable with key off or removing and reinstalling the clock fuse.
3. Retest for AM and FM operation. If the radio now operates, the electrostatic discharge condition has occurred. To prevent this condition from recurring, the receiver must be removed and sent to a Delco Repair Shop along with a claim tag indicating that it was disabled by an electrostatic discharge.
For warranty purposes, use labor Operation No. T6119 at .4 hour for R&R Receiver and Test for ESD.