Icom IC-R75 - SECTION 3 CIRCUIT DESCRIPTION; 3-1 RECEIVER CIRCUITS

■ Front panel
q POWER SWITCH [POWER]
➥ Push momentarily to turn power ON.
• Turn the optional DC power supply ON in advance.
➥ Push for 2 sec. to turn power OFF.
w HEADPHONE JACK [PHONES] (p. 8)
Accepts headphones.
• When headphones are connected, the internal speaker
or connected external speaker does not function.
e AF CONTROL [AF] (inner control)
Varies the audio output level from the speaker.
r RF GAIN/SQUELCH CONTROL [RF/SQL]
(outer control; pgs. 14, 30)
Adjusts the squelch threshold level. The squelch
removes noise output from the speaker (closed
condition) when no signal is received.
• The squelch is particularly effective for FM. It is also
available for other modes.
• The control can be set as the squelch plus RF gain
controls or squelch control only (RF gain is fixed at
maximum) in set mode.
t PASSBAND TUNING CONTROLS [TWIN PBT]
(p. 15)
Adjust the receiver’s “passband width” of the 455
kHz and 9 kHz IF filters for the inner and outer
controls, respectively.
• Set to the center positions when not in use.
y CLOCK MODE SWITCH [CLOCK] (p. 28)
Toggles between frequency indication and clock
indication when pushed.
u ANTENNA SELECTOR/SET MODE SWITCH
[ANT/SET] (pgs. 16, 30)
➥ While in a frequency indication, enters set mode
when pushed.
➥ While in a frequency indication, toggles between
the antenna 1 and 2 connectors when pushed
for 2 sec.
➥ While in the clock indication, enters time setting
condition when pushed for 2 sec.
➥ While in a timer indication, toggles the timer ON
or OFF when pushed.
i TUNING DIAL
Changes the displayed frequency, selects set
mode items, etc.
o TUNING DIAL TENSION LATCH
Adjusts the tension of the tuning dial.
!0 LOCK/SPEECH SWITCH [LOCK] (pgs. 13, 34)
➥ Toggles the frequency lock function ON and
OFF.
➥ Announces the selected readout frequency
when an optional UT-102 is installed and when
pushed for 2 sec.
2
2
PANEL DESCRIPTION
FIL
TS
CW/RTTY
FM
SSB
AM
PHONES POWER
RF/ SQL TWIN PBTAF
COMMUNICATIONS RECEIVER
DN UP
1 2
ABC
3
DEF
4
GHI
5
JKL
6
MNO
7
PRS
8
TUV
9
WXY
. 0
QZ
ENT
V/M MW
SEL SCAN
CLR
LOCK
AGCNBANFNRATT P.AMP
SET
CLOCK
ANT
Function display (p. 5)Speaker
q
w
e r t y i o !
0
!
1
!3
!4
!5!6!7!8
!2
u