Inside Views - Icom IC-718 Service Manual

SECTION 2
¡Top view (PA AND FILTER UNITS)
Predrive amplifier
(Q1: 2SC1971)
Drive amplifier
(Q2, Q3: 2SC3133)
Power amplifier
(Q4, Q5: 2SC2904)
¡Bottom view (MAIN AND PLL UNITS)
2nd mixer circuit
(D401: HSB88WSTR,
Rx; 455 kHz, Tx; 64.455 kHz)
Rx 1st IF amplifier
(Q1201: 3SK131)
Rx RF preamplifier
(Q1401, Q1402: 2SK2171)
Tx Mixer
(Q101, Q102: 3SK131)
Tx 1st IF amplifier
(Q151: 2SK882)
1st Lo amplifier
(Q201: 2SC4673)
Rx 1st mixer circuit
(64.455 MHz)
DDS gate allay IC
(IC6: SC-1245A)
PLL unit
+5V Reg.
(IC1: TA7805)
BFO DDS
(IC2: SC-1287)

INSIDE VIEWS

PA unit Filter unit
MAIN unit
2 - 1
Tx/Rx switching relay
(RL13: AG201344)
SWR detector
(L13: LR-391)
Tx low-pass filters
(L13: LR-391)
MIC amplifier
(IC2201: µPC5023)
FAN control-1
(IC2101: NJM2058M)
Tx 455 kHz Modulator
(IC2301: MC1495)
USB, LSB, CW, RTTY filter
(FI611: FL-65)
Rx 2nd IF amplifier
(Q1301: 3SK131)
FAN control-2
(Q3601: 2SD1664)
Tx 2nd IF amplifier
(Q502: 2SK882)
Reference oscillator circuit
(Q9: 2SC2714,
X1: CR-337, 32.000 MHz)