Garmin APOLLO GX SERIES Service Manual - page 147
of
166
Garmin AT
Rev --
© 2004 Garmin AT
GX Service Manual
10-17
Audi
o Amp/
M
odulator
12 VDC
Supply
5 / 3.
3 VDC
Supply
Boos
t
Supply
St
ar
tu
p
P
re-
Regulator
Buck
Supply
Input F
ilter
and Protection
Audio
Modul
a
+12 V
ol
t
Audio In
27
.5
V
D
C
Su
pp
ly
Sync
27.
5 VDC
27.
5 VDC Max
10
.8
V
D
C
+27.
5
V
+
3.3
V
o
+5 V
olt
s
Powe
r
Input
(10-40 VDC)
S
peake
r
Out
put
S
peaker
En
ab
le
Powe
r
Supply
(307 kHz)
Figure 10-12. VHF Comm Power Supply/Audio Amp Block Diagram