14
14
WM-FX481
1
2
36
35
34
33
32
31
30
29
28
27
26
25
13
14
15 16
17
18
19
20 21 22
23 24
48 47 46 45 44 43
42
41
40
39
38
37
COM
RI
VREF
POWER OUT
(COM)
POWER OUT (R)
VCC
POWER MUTE
POWER IN (L)
POWER IN (R)
MIX OUT (L)
MIX OUT (R)
LP.2
HP IN (R)
HP IN (L)
DET OUT
MVREF
IN
+
VSP
MIX IN (R)
MIX IN (L)
LOW BOOST SW
M-GND
R.VREF
SYSTEM
POWER OUT (L)
POWER GND
MVCC
DR
WOUT
MP-GND
VOUT
UOUT
FC
OUT
OSC
UB
VB
WB
3
4
5
6
7
8
9
10
11
12
PRE NF (L)
PRE OUT (R)
PRE NF (R)
FWD IN (R)
REV IN (R)
REV IN (L)
FWD IN (L)
S/S
PRE GND
PRE OUT (L)
BIAS
R.F
REF
SYS
CONT
DET
VREF
SPEED
LOW
BOOST
PRE DRIVER
OPERATION LOGIC
OSC
PLUSE DET
REF
VOLTAGE
REF VOLTAGE
FOR SPEED CONTROL
CURRENT
DET
OPERATION
DET
FWD/
REV
FREQ
CARC.
+
–
Note on Schematic Diagram: MAIN SECTION
• All capacitors are in
µ
F unless otherwise noted. pF:
µµ
F
50 WV or less are not indicated except for electrolytics
and tantalums.
• All resistors are in
Ω
and
1
/
4
W or less unless otherwise
specified.
•
f
: internal component.
•
C
: panel designation.
•
: B+ Line.
•
H
: adjustment for repair.
• Power voltage is dc 3V and fed with regulated dc power
supply from battery terminal.
• Voltages and waveforms are dc with respect to ground
under no-signal (detuned) conditions.
• no mark : FM
(
) : AM
<
> : PLAY(TAPE)
• Voltages are taken with a VOM (Input impedance 10 M
Ω
).
Voltage variations may be noted due to normal produc-
tion tolerances.
• Waveforms are taken with a oscilloscope.
Voltage variations may be noted due to normal produc-
tion tolerances.
• Signal path.
F
: FM
f
: AM
E
: PB
• Abbreviation
CH
: Chinese
9E
: No Indication of country of origin
5E, 6E : Indication of country of origin
z
Waveforms
1
IC702
1
VOLT/DIV : 500 mV AC
TIME/DIV : 5
µ
sec
XOUT
1.5 Vp-p
13.5
µ
sec
• IC BLOCK DIAGRAMS
IC1 CXA1960Q
IC301 LB8115W-NA-TLM
+
–
12
13
14
19
15
TVIN
MREF
GND
FMIB
IFCT
NC
FMIN
FMR
O
OLAG
ARFI
REGV
TVRO
FTLO
BAND
TUNE
PLLO
FALC
COMP
37
38
39
40
AAGC
DETO
PLT2
MPXI
MPRM
V12M
MUTE
PLT1
PLL1
PLL2
MPX DECODER
AM BPF
PSN
1/X
FM/TV
LPF
PD
VCO
1/2
1/2
STID
14V
PLAP
TUNE
38kHz
STEREO AUDIO R
STEREO AUDIO L
19kHz
1.65V
1.25V
36
8 9
10
VCO
STID
MCNT
GND
VCC
1
4
2
3
5
6
MPRG
LOUT
ROUT
DDCN
PLLI
7
+
–
+
–
35
34
FM DET
150kHz
FM LMT
OL DET
TV RF
AMP
FM RF
AMP
AM RF
AMP
45kHz
31
32
33
MUTE
AGC AMP
AM AGC
1.25V
AM/FM: 1/2
TV: 1/8
1.25V
18
17
16
FMBF
AMLO
AM OSC
FM/TV OSC
20
30
29
27
28
23
24
25
26
22 21
11
w w w . x i a o y u 1 6 3 . c o m
Q Q 3 7 6 3 1 5 1 5 0
9
9
2
8
9
4
2
9
8
T E L
1 3 9 4 2 2 9 6 5 1 3
9
9
2
8
9
4
2
9
8
0
5
1
5
1
3
6
7
3
Q
Q
TEL 13942296513 QQ 376315150 892498299
TEL 13942296513 QQ 376315150 892498299
http://www.xiaoyu163.com
http://www.xiaoyu163.com
