Radio - Inoperative Due to Logic Lock Up

87buick8

Bulletin: 87-9-4

Date: Sept., '87

Ref. No. 87-174-9

Corp. Ref. No. 739002

SUBJECT: RADIO INOPERATIVE DUE TO LOGIC LOCK UP

MODELS AFFECTED: ALL 1987 ELECTRA/PARK AVENUE, LESABRE, REGAL, CENTURY, SOMERSET, SKYLARK AND SKYHAWK MODELS WITH 2000 SERIES RADIOS AND THREE BUTTON CASSETTES, OPTION UM6

2000 SERIES RADIO WITH 3 BUTTON CASSETTE:

Some 1987 vehicles with 2000 series radios and three button cassettes (Option codes UM6) 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 Center for the addition of circuit protection against future ESD damage. If the radio is not sent to an AC Delco center for repair, the customer may experience the same condition again.

When submitting the radio to the repair center, describe the problem as "Radio Logic Lock-up". This description is necessary because the radio will appear normal when tested out of the car.
Use applicable labor time.