Figure 4-1. Vco Block Diagram - Vhf Band - Motorola ASTRO Digital Spectra Plus Detailed Service Manual

4-14
AUX 1
J601-11
PIN DIODE
DRIVERS
J601-3
+SL
J601-4
VCO
-SL
J601-10
MOD
SYNTHESIZER
FEEDBACK
GPW-5867-O
September 5, 2008
AUX 2 SF 8.6
J601-9 J601-12
BIAS
Q3645
VCO SUBSTRATE
J601-1
PAD
K9.4
5V
5V
REG.
U3675
Figure 4-1. VCO Block Diagram – VHF Band
Troubleshooting Procedures: VCO Procedures
LOW
PAD
PASS
FILTER
_ . . 2
Q3676
U3676
RANGE
RX1
RX2, TX1
TX2
TX3
9.6
J601-2
BIAS
RX INJECTION TO
RECEIVER FRONT
END > + 19dBm
Q3675
J3642
K9.4
J601-5
BIAS
J3641
PAD
TX INJECTION TO
PA > +9dBm
AUX1 AUX2
>8Vdc >8Vdc
<1Vdc >8Vdc
>8Vdc <1Vdc
<1Vdc <1Vdc
6881076C25-E