Motorola PM1200, Базовое руководство по обслуживанию

Страница: 27 / 138

Chapter 2 Basic Maintenance
2.1 Introduction
This section of the manual describes preventive maintenance, handling precautions, and some basic
repair procedures and techniques. Each of these topics provides information vital to the successful
operation and maintenance of your radio.
2.2 Preventive Maintenance
Radios are shipped from the factory with a worst-case frequency error of:
• ±10 ppm for Low Band (A) 29.7
–
37 MHz
• ±10 ppm for Low Band (B) 37
–
50 MHz
For radios that have been in storage for over six months from the factory ship date, the reference
oscillator should be checked when the radio is initially deployed to the field. It is strongly
recommended that the reference oscillator be checked every time the radio is serviced or at least
once a year, whichever comes first. The crystal contained in the reference oscillator naturally drifts
over time due to its aging characteristic. Periodic (annual) adjustment of the reference oscillator is
important for proper radio operation. Improper adjustment can result in both poor performance and
interference with other users operating on adjacent channels.
2.2.1 Inspection
Check that the external surfaces of the radio are clean, and that all external controls and switches
are functional. A detailed inspection of the interior electronic circuitry is not needed.
NOTE: Verify that all dust covers are in place.
2.2.2 Cleaning
The following procedures describe the recommended cleaning agents and the methods to be used
when cleaning the external and internal surfaces of the radio. External surfaces include the control
head and radio chassis. These surfaces should be cleaned whenever a periodic visual inspection
reveals the presence of smudges, grease, and/or grime. Internal surfaces should be cleaned only
when the radio is disassembled for servicing or repair.
The only recommended agent for cleaning the external radio surfaces is a 0.5% solution of a mild
dishwashing detergent in water. The only factory recommended liquid for cleaning the printed circuit
boards and their components is isopropyl alcohol (100% by volume).
The effects of certain chemicals and their vapors can have harmful results on
certain plastics. Aerosol sprays, tuner cleaners, and other chemicals should
be avoided.
!
C a u t i o n