Marantz CDR500 F1B Service Manual page 31

8.3.7 HF Path
Description
The pre-amplified HF-signal is presented to both n=1 and n=2
amplifier circuits. The mux/demux switches via software and
micro processor controlled S1 and S2 lines between either one
of the amplified n=1 or n=2 signals. The signal will then follow
n-dependant filtering
n=1 AMP
3173 3174
430R 430R
2143
330p
2
n=2 AMP
E AMP
3191
3192
430R
430R
2164
180p
DC Settings
Set the power and reset connections as described above in
"1.1.1. Supply Voltages". Check the following voltages :
Force Pin
Emitter
S1 and S2 "HIGH" Collector
S1 and S2 "LOW" Collector
S1 and S2 "HIGH" 13
S1 and S2 "LOW" 13
S1 and S2 "HIGH" 3
S1 and S2 "LOW" 3
+5VHF
HFGND
HFGND
7023
BFS20
HFGND
390p
2149
680p
HFGND
+5VHF
HF
7009
BFS20
HF
HFGND
HFGND
Location Measure
7006 2.4
7010 1.9
7010 1.9
7025 1.6
7025 1.6
7025 3.2
7025 3.2
CL96532086_058.eps
Figure 8-29
another amplification and filtering circuit. The filtering again is
controlled by the S1 and S2 lines, dependant on whether the
disc starts up (speed n=1, S1 and S2 Low), disc plays at speed
n=1 (S1 Low, S2 High) or disc plays at speed n=2 (S1 and S2
High).
DUAL 4 CHANNEL
MUX/DEMUX
+5VHF 7025
74HCT4052D
2130
10
16
VCC 0
0
100n 4x 9
7
3
VEE 1
6
8
GND G4
HFGND 1
0
5 HFGND
1 3
2
2
HF
4
3
2141
12
2n2 14
13
2146
15
1n5 11
9
+5VHF
HF
HFGND HFGND
1K
3196
BC858B
7007
7010
BC848B
HFGND
HFGND
Figure 8-28
±
10%
±
10%
±
10%
±
10%
±
10%
±
10%
±
10%
080999
1-29
3
S1
S2
HFGND HFGND
HFIN
2142 F309
2145
22n
F156
3178
HFGND F310
47p
1K 3181
2150
22K
47n
HFGND
7000
SAA7324
1 HFREF
2
HFIN
3
ISLICE
F159
FRONT
4 VSSA1
END
5
VDDA1
CL96532086_057.eps
080999