RADIO INOP AFTER TAPE OPERATION

RADIO INOP DUE TO LOGIC LOCK UP

VEHICLES AFFECTED: ALL 1987 VEHICLES WITH 2000 SERIES RADIOS ------------------ AND THREE BUTTON CASSETTES (OPTION CODES UM6, UU6 AND UK5)

Some 1987 vehicles with 2000 series radios and three button cassettes (Option codes UM6, UU6 and UK5) may exhibit a condition in which the radio portion of the unit is inoperative with the cassette deck operating normally. This is caused by an internal radio "logic lock up" situation resulting from electrostatic discharge (ESD) through the tape deck door.

To check for this condition, remove the vehicles' battery power by disconnecting and reconnecting the negative battery cable. - If the radio returns to normal operation after this is done, it should be sent to an AC Delco service centre for the addition of circuit protection against future ESD damage. If the radio is not sent to an AC Delco centre for repair the customer may experience the same condition again.

When submitting the radio to the repair centre, describe the problem as "Radio Logic Lock-Up". This description is necessary because the radio will appear normal when tested out of the car.

General Motors bulletins are intended for use by professional technicians, not a "do-it-yourselfer". They are written to inform those technicians of conditions that may occur on some vehicles, or to provide information that could assist in the proper service of a vehicle. Properly trained technicians have the equipment, tools, safety instructions and know-how to do a job properly and safely. If a condition is described, do not assume that the bulletin applies to your vehicle, or that your vehicle will have that condition. See a General Motors dealer servicing your brand of General Motors vehicle for information on whether your vehicle may benefit from the information.