Chapter 2 Basic Maintenance; Introduction; Preventive Maintenance; Reference Oscillator - Motorola ASTRO SPECTRA Service Manual

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 ±200 Hz for VHF, ±300 Hz
for UHF, and ±500 Hz for 800 MHz. These specifications are tighter than the most stringent FCC-
required specifications of 2 ppm (parts per million) for both VHF and UHF, and 1.5 ppm for 800 kHz,
within which the radio will operate to specification.
2.2.1

Reference Oscillator

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.
A recommended test setup and tuning procedure is detailed in Chapter 6. Radio Alignment
Procedure. The frequency counter used for this procedure must have a stability of 0.1 ppm or better.
2.2.2

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.
2.2.3

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 (70% by volume).