JVC KS-FX945R Service Manual page 26

6.4 CXA2560Q (IC401) : Dolby B type noise reduction system with play back equalizer amp.
• Pin layout & block diagram
30 29 28 27
7k/12k
PBFB2
31
100k
PBRIN2
32
300k
-
1
PBGND
33
+
F2
PBFIN2
34
30k
VCT
35
45k
PBREF
36
30k
PBFIN1
37
F1
+
PBGND
38
-
1
300k
PBRIN1
39
100k
7k/12k
PBFB1
40
1 2 3 4
• Pin function
Pin No. Symbol I/O
1 PBTC1 -
2 PBOUT1 O
3 OUTREF1 O
4 TAPEIN1 I
5 Vcc -
6 NC -
7 LINEOUT1 O
8 TCH1 -
9 NC -
10 MSLPF -
11 G2FB -
12 G1FB -
13 MSTC -
14 MSOUT O
15 NC -
16 NRSW I
17 MUTESW I
18 TAPESW I
19 DRSW I
20 MSMODE I
21 MSSW I
22 NC -
23 TCH2 -
1-26 (No.49875)
26 25 24 23 22 21
NR MSMODE
20
OFF/B
DRSW
19
T2
MS MODE
BIAS
TAPESW
18
MUTE
MUTESW
17
TAPE EQ
NRSW
NR MODE
16
FWD/RVS
NC
15
Vcc
MS ON/
LPF OFF
+
MSOUT
14
-
DET
F3 MSTC
13
T1
G1FB
12
OFF/B
G2FB
11
NR
5 6 7 8 9 10
Function
Playback equalizer amplifier
capacitance
Playback equalizer amplifier
output
Output reference
TAPE input
Power supply
Line output
Time constant for the HLS
Cut-off frequency adjustment
of the music sensor LPF
Music signal interval detection
Music signal interval detection
Time constant for detecting
music signal interval
Music sensor out
No use
Dolby NR control
Mute function control
Playback equalizer amplifier
control
Head select control
Music sensor mode control
Music sensor control
Time constant for the HLS
Pin No. Symbol I/O
24 LINEOUT2 O
25 DIREF -
26 GND -
27 TAPEIN2 I
28 OUTREF2 O
29 PBOUT2 O
30 PBTC2 -
31 PBFB2 I
32 PBRIN2 I
33 PBGND -
34 PBFIN2 I
35 VCT O
36 PBREF O
37 PBFIN1 I
38 PBGND -
39 PBRIN1 I
40 PBFB1 I
Function
Line output
Resistance for setting the
reference
Ground
TAPE input
Output reference
Playback equalizer amplifier
output
Playback equalizer amplifier
capacitance
Playback equalizer amplifier
feedback
Playback equalizer amplifier
input
Playback equalizer amplifier
ground
Playback equalizer amplifier
input
Center
Playback equalizer amplifier
reference
Playback equalizer amplifier
input
Playback equalizer amplifier
ground
Playback equalizer amplifier
input
Playback equalizer amplifier
feedback