Motorola ASTRO SPECTRA Service Manual

6881076C20-E February 3, 2003
Basic Troubleshooting: Synthesizer Troubleshooting 9-13
Synthesizer
Malfunctioning
Synthesizer Not Locked Check the synthesizer lock line (pin 14 of
J500).
If > 1 V, then the synthesizer is not locked.
Go to Does Not Lock on Some Channels
above.
Reference Oscillator
Not On Frequency/
Working
1. Check the reference oscillator
frequency.
It should be 16.8 MHz ±4 Hz.
THIS MUST BE MEASURED @ 25° C
(77° F) TO BE ACCURATE.
2. Retune the reference oscillator if
frequency is incorrect.
VOCON Board If the reference oscillator will not tune on
frequency, is reference control voltage (pin
2 of J500) tuning 1.5 to 3.0 volts, and is
the 5 volt supply 5 V ±.2 V? If not, replace
the VOCON board.
Programming
(EEPROM)
Check mode programming information to
ensure that the correct frequency
programming information has been
entered.
RF Board Replace the RF board.
Table 9-7. Synthesizer Troubleshooting Chart (Continued)
Symptom Possible Cause
Correction or Test (Measurements
Taken at Room Temperature)

Motorola ASTRO SPECTRA Specifications

General

Frequency Range	136-174 MHz, 403-470 MHz
Number of Channels	Up to 255
Channel Spacing	12.5 kHz, 20 kHz, 25 kHz
Modulation	FM
Operating Temperature	-22°F to +140°F (-30°C to +60°C)