3 - 6
The CPU has the clock function. Thus, the CPU and the
clock function have the crystal separately. The CPU has the
9.8304 MHz crystal (X112) for the CPU clock, and then the
oscillated 9.8304 MHz signal is applied to the IC101, pin 7
and 8. The clock function has the 32.768 kHz crystal (X111).
The oscillated 32.768 kHz signal is applied to the CPU
(IC101, pin 4 and 5).
When the power is “OFF”, the EEPROM (IC231) is used for
keep on saving the data of memory channels, and so on.
3-3-2 RESET CIRCUIT (LOGIC UNIT)
The reset circuit consists of Q391, D381, D382, D393, IC391
and IC392. When IC-R75 is supplied 13.8 V to connect the
AC adapter, the “HV” signal is applied to the IC391, pin 2.
The signal which is output from the IC391, pin 1 is applied to
the IC392, pin 1. The signal is applied to the Q391, and is
then output to the CPU (IC101, pin 9) as “CRES” reset sig-
nal.
A portion of the output signal from the IC392 is input to the
CPU (IC101, pin 82) as “BKUP” signal to backup the clock
data.
3-3-3 BACKUP SWITCH CIRCUIT (LOGIC UNIT)
IC-R75 has a backup switch circuit (Q511 and Q512). When
IC-R75 is supplied to 13.8 V to connect the AC adapter, the
“H5V” signal is applied to Q512, pin 4, and then Q511 is OFF.
When the AC adapter is disconnected, the “BATT” signal
from the battery (MAIN unit; BT1521) is applied to the Q511,
and then Q512 is OFF.
The output signal is applied to the CPU (IC101, pin 31) as
“B5V” signal to keep on working the clock function.
The backup battery is not used while the AC adapter is con-
nected.
Description
The voltage from the connected DC power sup-
ply.
Common 5 V converted from the “HVR” line by
the +5 regulator circuit (IC1361).
Common 14 V converted from the “”HVR” line by
the regulator circuit (IC1371 and D1371). The
output voltage is applied to the pre-amplifier
(Q381 and Q382) via the PRE1 regulator circuit
(Q383) and the IF-amplifier (Q471) via the R14V
regulator circuit (Q472).
Receive 8 V converted from the “14V” line by the
R8 regulator circuit (Q1381, Q1382 and D1381).
The output voltage is applied to the IF-amplifier
(Q912, Q471), the switch control circuit (Q151),
and the driver circuit (IC561 and IC562, pin 9).
Common 8 V converted from the “14V” line by
the +8 regulator circuit (IC1391). The output sig-
nal is applied to the low-pass filter (IC1211A, pin
4), buffer amplifiers (Q1051 and Q801), the pre-
amplifier (IC391) via the REG2 regulator circuit
(Q391) and the AM detector circuit (IC2001, pin
25).
Common 5 V converted from the “14V” line by
the +5 regulator circuit (IC1401).
Common –5 V converted from the “14V” line by
the –5 V DC-DC convertor circuit (IC1411, D1412
and D1413).
Line
HVR
H5V
14V
R8V
8V
5V
–5V
3-4 POWER SUPPLY CIRCUITS
3-4-1 VOLTAGE LINES (MAIN UNIT)
