Product Support Bulletin 822

LAND MOBILE PRODUCT SECTOR PSB # 822 1301 E. ALGONQUIN RD. APC # 509 SCHAUMBURG, IL. 60196 DATE: OCTOBER, 97 (847) 576-0180 EXPIRES : 11/30/98   SUBJECT: QUANTAR STATIONS WITH INTERMITTENT RECEIVER AND /OR EXCITER L01 LOCK ALARMS MODELS AFFECTED : T5365A MODULES AFFECTED: TRF6551G (RECEIVERS), AND TLF6920E/F (EXCITERS) SYSTEMS AFFECTED : CONVENTIONAL AND TRUNKING SYMPTOMS: THE RECEIVER AND/OR TRANSMITTER WILL INTERMITTENTLY BE INOPERABLE. NO RECEIVER AUDIO WILL BE GATED, AND THE TRANSMITTER WILL NOT KEY ( OR WILL DEKEY IF ALREADY KEYED). THE RX FAIL LED AND/OR THE TX LOCK LED WILL FLASH INDICATING AN OUT OF LOCK CONDITION WITH THE RECEIVER OR EXCITER VCO. THE DIAGNOSTIC ALARM LOG WILL INDICATE RX-LOCK-FAIL AND/OR TX-LOCK-ALARM. CAUSE: Contaminant at the interface between the vibration pad and the bottom of the receiver or exciter PC boardcauses growth of a leakage path on the VCO steering line, which can cause the out-of-lock detector to be activated. High humidity contributes to the problem but is not the sole cause. SOLUTION : Replace vibration pad Motorola part # 7585064U01 with Motorola part # 7585064U02, which has cutouts in the area which causes the contact problems. Only stations experiencing the diagnostic out-of-lock errors need to have this service performed. NOTE Remove FRU module covers and remove PC board from the FRU housing paying attention to the RF connector (RCVR. INPUT) or (EXCITER OUTPUT) by removing the nut that holds the connector to the housing. The rubber vibration pad is located underneath the PC board and is held in position by two embosses in the sheet metal. It is important to orient the new pad in the same location as the old pad and use the embosses to secure the pad in position while screwing the pc board back in the FRU housing. All stations shipped after August 8, 1997 contain the new vibration pad. The pad can be obtained at no charge from the Americas Parts Division by making reference to this bulletin #. No reference to warranty is implied or intended.