Product Support Bulletin 847

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LAND MOBILE PRODUCT SECTOR

1301 E. ALGONQUIN RD. SCHAUMBURG, IL. 60196

(847) 576-0180

PSB # 847

APC # 448,509,225,360,590,675,537,301,482,409,218,676

DATE: SEPTEMBER ,1998

EXPIRES: 9/30/99

SUBJECT: QUANTAR/QUANTRO STATIONS DRIFTING OFF FREQUENCY

MODELS AFFECTED : All T5365A QUANTAR/QUANTRO STATIONS THAT INCLUDE THE UHSO (ULTRA HIGH STABILITY OSCILLATOR) OPTION X873

SYSTEMS AFFECTED : CONVENTIONAL AND TRUNKING

ISSUE:

The Receiver and Transmitter will drift off frequency by approximately 30Khz. Station alarms may or may not be generated to let the user know of the fault.

CAUSE:

Marginal power out of the ovenized oscillators will cause a miscount of the 5Mhz pulses. The result will be that the 5Mhz reference frequency will be counted as a lower frequency and the Pendulum IC will fail to lock on to the reference frequency.

RESOLUTION:

On the TTN5070C module change the value of R609 from 10K ohms to 2.7K ohms P/N 06-11079A84 and change the value of R611 from 56 ohms to 39 ohms P/N 06-11079A40 (Diagram 1).

 

NOTE: The above referenced resistors can be obtained at no charge from the Americas Parts Department by calling 1-800-422-4210 and making reference to this bulletin.

 

Authorized Motorola Service Shops will be allowed 1 hour per station to change the resistors and check out station operation by making reference to this bulletin and entering the standard labor claim form RO21-19.

 

Front of Board

R609 E400 Q601 Q602 R611 R615 C610 C611

J101 Y600

 

 

DIAGRAM 1