M 37-DC
Schaltpläne und Druckplattenabbildungen / Circuit Diagrams and Layout of PCBs
GRUNDIG Service
4 - 1
Sc
haltpläne und Druc
kplattenabbildung
en / Cir
cuit Dia
grams and La
y
out of PCBs
Blockschaltplan / Block Diagram
300mV
1u
470R
470R
1u
500mV
OUT
SUBWOOFER
ETF2
-CMOS
BC848C
BC848C
L/R
+12A
+12M
+5V6
+C
+B2
+A L/R
+12M
NTC
F1
F2
+A
+B2
+B1
+C
AN7164
-
-
+
+
+A
+C
+B1
TMP87CS71F
uP
ATTN
2X6 ohms
23W
AF3
1100mV
A=19dB
Zi=27K
+
( Dolby )
for ref. operating level
Note : levels indicated
-30V
+F
SA
I C
2
Lt/Rt
FTD
VOLUME
CONTROL
KEY MATRIX
EEPROM
IR EYE
RDS
DECODER
TUNER
CONTROL
CDC
CONTROL
AF2/AF3
CONTROL CD STBY
HP_SENSE
MUTE
POWER
CONTROL
TAPE
CONTROL
NTC
PW_DN
STBY
AMP_ON
CDC
CONTROL
DSC
LEDS
CDC
LEDS
LED
SOUND
INC
20 msec
FIXED DELAY
( 0 DEG. )
DECODER
EXPANDER
N
L
+9V
24mV
HEADPHONE
+5.6V
+5.6V
CONTROL
SUPPLY
CD
+12M
+12A
+CD
+12A
Volume2
Treble
Bass
Volume2
LOGIC CONTROL
2
I C
SELECTOR
SOURCE
SOFAC (TEA6321T)
350mV
120mV
275mV
150mV
1kHz
-6dB track
400Hz
200nWb/m
TUNER
CDC3
AUX
Atten
Atten
Atten
Atten
FRONT LEFT
REAR LEFT
INCREDIBLE SOUND
MUTE
MUTE
32 Ohm
15mW
+12A
+12A
HEADPHONE
+9V
REG.
REAR RIGHT
HEADPHONE
AMPLIFIER
AM 80% mod,
1kHz
FM
∆
f=67.5kHz,
1kHz
-30V
S
C
C/S SOFAC
( 180 DEG. )
300mV
CENTER &
SURROUND
ML
470n
470R
22K
L/R SELECT
C/S SELECT
I C1
2
Ri>=20K
I C1
2
HP SENSE
+5.6V
HP_SENSE
+CD
(+5V)
CD STBY
+9V
POWER AMPLIFIER
23W
Ri=56K
12 ohms
Zi=56K
L/R
6 ohms
45W
Ri=3K
560R
2600mV
12K
10K
+5.6V
F1
+F
+F
+F
+F
Atten
ATTN
ATTN
+A C/S
+
+
-
AN7164
AN7164
-
-
+
+A
I C DATA
I C CLK
2
2
+C
+B2
+C
+B2
F2
+F
Voltage
Selector
+C
STD-BY
TRAFO
ECO
DPL
CONTROL
MUTE
I C
2
-32V
Volume1
Volume1
LEGEND :
+
-
500mV
OUT
SURROUND
MUTING
CIRCUIT
22K
22K
100p
100p
Ro<=1K
Vref
15K
22K
82K
4K7
1K2
1K8
110mV
300mV
110mV
500mV
47R
47R
220K
220K
ATTN
BUFFER AMP
Ro<=2K
L-CHANNEL
110mV
FRONT
POWER SUPPLY
175mV
175mV
CENTER
SURROUND
3200mV
+12A
300mV
MUTE
ECO DPL
mV
: MUTE L/R CHANNELS
SUPPLY VOLTAGES
AC SIGNAL LEVEL
SIGNAL FLOW (MAIN & CONTROL)
: MUTE CENTER & SURROUND WHEN
PLUG IN HEADPHONE
R-CHANNEL
