Furuno FAX-30 Service Manual page 15

The synthesizer consists of 18 MHz oscillator, Direct Digital Synthesizer (DDS), PLL and VCO.
The signals from MAIN board, RCV DATA, RCV CLK, RCV DDS, RCV PLL and RCV BAND,
determines the frequency of the local oscillator depending on the selected receiving frequency.
When the synthesizer unlocks, RCV UNLOCK signal is generated for the error message.
The VCO is adjusted as follows.
Setting frequency
29.9999 MHz
25.5000 MHz
25.4999 MHz
21.5000 MHz
21.9999 MHz
17.5000 MHz
17.4999 MHz
13.5000 MHz
13.4999 MHz
9.5000 MHz
9.4999 MHz
6.0000 MHz
5.9999 MHz
3.0000 MHz
2.9999 MHz
0.0800 MHz
Adjuster
T7 8.9 V to 9.1 V
No adjuster 5.3 V or more
No adjuster 8.0 V to 9.5 V
No adjuster 5.3 V or more
T6 8.9 V to 9.1 V
No adjuster 5.3 V or more
No adjuster 8.0 V to 9.5 V
No adjuster 5.3 V or more
T5 9.2 V to 9.4 V
No adjuster 5.3 V or more
No adjuster 8.0 V to 9.5 V
No adjuster 5.3 V or more
T4 8.9 V to 9.1 V
No adjuster 5.3 V or more
No adjuster 8.0 V to 9.5 V
No adjuster 5.3 V or more
Voltage at TP4
7
Chapter 2 Circuit Description