BBK AV210 User manual

ENGLISH
AV210
SERVICE MANUAL

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Cir cui t Makeup................................................................................................1INPUTPART.....................................................................................................2...................................................................................................................................5.MicrophoneCircuit............................................................................................6.PowerAmplifi cationandProtectionCircuit.........................................................
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..................................................................I NSTRUCT I ONSTOTHE CI RCUI TS 1.THEFRONTCONTROLPANEL.........................................................................2.THEMAINAMPPART........................................................................................
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..................................................THEE XPL ANATI ONFORKEYCOMPONENTS CPUICW78E54..............................................................................................volumecontrolICM62446................................................................................EcholCPt2399................................................................................................
Vol umeadj ust ment , soundf i el dpr ocess i ngandEQadj ust ment ci r cui t s3. I nput si gnal sdet ect , sear chandf r equencys pect r umsampl i ngci r cui t s. 4. Contr ol Ci r cui t . 1
1
3
3
4
8
10
12
12
16
24
24
25
27
CAUTIONS
There is high voltage inside this unit. Make sure to pull out the plug of this unit before
repairing!
There are many high voltage components inside this unit. Please pay attention to all
warnings and instructions marked on this unit to avoid electric shock!
Specifications of the replaced components must be the same as that of the original
components. Do not change the components' specifications to prevent risks!
CONTENTS
- 27 -
Echo IC Pt2399

- 1 - - 26 -
¢ñCi r cui t Makeup
1. INPUT PART
AV210 has three ways of the analog audio source input and one group of 5.1 channel input
jacks. Their switch is realized by the electronic switch. The circuit incorporates two kinds of
electronic switch IC: CD4052 (dual channel one out of four electronic analog switch) and
Cd4053 (trio channel one out of two electronic analog switch). Their real value tables are as
follows:
A
B
X0 X1 X2 X3
0
00
0
1
1
1
1
CD4052 REAL VALUE TABLE
A
1
XBYC
0
X1 1
Y0
0
Y1
0
1
X0
Z
Z0
Z1
CD4053 REAL VALUE TABLE
There are stilltwo important controlsignals SELand SEL1 inthis circuit. WhenSEL is
high level, thecircuit is inthe mode of5.1 CH inputfrom outside. WhenSEL1 is high
level, the circuitis in thecyber logic mode.When both ofthem are lowlevel, the circuit
is in theHi-Fi mode (directmode) and thestandard sound fieldprocessing mode. They
work in thefollowing steps.
When pressing the INPUT button, the levels A and B from
the pins 38 and 39 of the CPU N422 are added into the pins 9 and 10 of the electronic
switch N401. The electronic switch selects the input mode circularly from VCD, CD,
AUX and 5.1CH according to different combinations of levels A and B. It can be divided
into two modes: 5.1CH and three analog input modes. Their signals' flow is as follows:
1.1 5.1CH input mode: In this mode, A and B are high levels, L and R channel signals
are sent out from the pins 3 & 13 of N401. Then the levels reach IC N402 to be master
volume adjusted after amplified by N407A and N407B. At the same time, the pin 32 of
CPU N422 sends out a high level to the electronic switch N410's pins 9, 10 and 11 (SEL
control signal). C, SR and SL signals are sent out from the N410's pins 14, 15 and 4
to IC N402 where separate volumes are adjusted. SW signals (D-SW) is sent to the IC
N402's where the volume is adjusted. Therefore, the 6 channel signals of 5.1 CH input
are selected by the electronic switch and added into the electronic volume adjusting IC
where the separate volume adjustment is performed. Then the signals pass to the rear
circuit, the whole unit's input source is selected as 5.1CH input mode.
1.2 Three analog input mode: Press the INPUT button to select one of the VCD, CD
and AUX. The select function is performed when the control levels A and B from the pins
38&39 of the CPU N422 are added to the pins 9&10 of the electronic switch N401. The
signals of L& R channels are sent out from the pins 3&13 and then amplified in the oper
ational amplifier N407A and N407B. AV210 incorporates three processing modes to the
signals: Hi-Fi, Cyber Logic and standard stereo. Their signal's flow is as follows:
1.2.1 Standard StereoProcessing Mode: The L & R channelsignals from theN407A
and N407B areadded to theIC N402 wherethe electronic volumeis adjusted.At the
same time, asignal selected fromthe L channel passes N408Aand N406B wherethe
signal is processedthrough low passfilter to obtaina subwoofer signal(S-SW). S-SW
is added toN411's pin 5 andthe pin 9(SEL) is lowlevel. Accordingto the realvalue
table, S-SW signalis sent outfrom the pin4 to N402'spin 6 wherethe electronic volume
is adjusted. Inthis mode, thisunit is inthe three channeloutput mode.

- 2 -- 25 -
1.2.1 Hi-Fi ProcessingMode: The signal flow is the same asthat of the standard stereo
mode. The electronic volume adjustingIC N402 shut off other audio channels under the
control of theCPU. Neither the sound fields processing and balance adjustment can be
performed. Therefore, S-SW cannot besent out andthe whole unit is in the two channel
output mode.
1.2.3 Cyber Logic:L&R channel signalssent out fromN407A and N407B reach the IC
N402 where theelectronic master volume is adjusted. Meanwhile, the signals selected
from the channelL passes through the low pass filter N408Awhere it isdivided into two
lines. One linereaches the pin 13 of N411 through R657and another line reaches the
pin 5 ofN411 after it is amplified through the low pass filter N406B. The signal selected
from the channelR reaches the pin 1 of N411 after being amplified through the lowpass
filter N408B. N411's pin 9 (SEL) is thelow level.According to the real value table, the
S-SW signal sentout from the pin 4 is added to the pin 6 ofN402 where theelectronic
volume is adjusted.The pins 10&11 (SWLL) are highlevel. According to the real value
table, the centralchannel signal (S-C) sent out from the pin 14 of N411 and the surround
channel signal (S-S)sent out from the pin 15 of N411 are addedto the pins 12, 2 and5
of N410. (TheS-S is divided into two signalssurround left and surround right.) Atthis
time, the pins9, 10 and 11 (SEL) are low level. According to the realvalue table, these
three lines ofsignals sent out from the pins 14, 15 and 4 reach theIC N410 wherethe
volume is adjustedseparately. This unit is in thesix-channel output mode.
The relationship ofall input source switches and sound processing mode is shown as
Figure 1.
Press the INPUT
button to select
circularly
Three modes
input
Hi-Fi mode Only L & R channel outputs,
Sound fields and
EQ settings are invalid
Only L,R & SW channel outputs,
Capable of setting the
Concert sound field and EQ
6 CH output, capable of setting
the Theater sound field and EQ
6 CH output, capable of setting
the Theater sound field and EQ
Standard
Stereo
mode
Cyber Logic
mode
5.1 CH input
(Figure 1)
volume control ICM62446

- 3 - - 24 -
2. Volume adjustment, soundfield processing andEQ adjustment
circuits.
All channel signalsare sent to N402 inside which the independent volumeadjustment,
EQ adjustment andall sound field modes process are performed.
The sound fieldprocessing and EQ adjusting circuit is mainly processing theL&R
channel signals.According to the schematic diagram, the L&R channel signalsare
added simultaneously tothe pins 15, 17, 13 and 16 of N402.When the unit mode is in
the Hi-Fi mode,the internal circuit of the pins 17&16 is connectedand the other input
signals are cutoff. At this time, only the L&R channel volume canbe adjusted and only
the pins 31&32send out signals. Therefore, the unit is in the 2CH outputmode. The
unit mode isnot in the Hi-Fi mode, other input signals areconnected but the pins
17&16 signals arecutoff. At this time, all channel volumes can be adjusted
independently and thesound field processing or EQ adjusting of the L&Rchannels
can be performed.Finally, all channel signals pass out from the pins 31,32, 33, 34,
35&36. The SW channel signalfrom the pin 36 reaches the amplified speakers tobe
amplified through theSW output terminals. Other channel signals reach to thepower
st
amplifying circuit tobe amplified. The L&R channel signals will go through 1 grade
LPF and MIXamplification (Karaoke signals are overlapped into L& R channels).
3. Input signalsdetect, search and frequency spectrum samplingcir
cuits
3.1 Input signalsdetect and search circuit: The six channel signal lines of theinput IC
N402 are connectedwith 100K sampling resistors R533, R534, R657, R676 andR678
respectively. The signals are mixed bythese resistors and added to the opposite-phase
input terminal tobe amplified. VD431 and C481 connected to N403B's outputend
constitute half-wave rectifyingfilter circuit. Then the signals reach the voltage comparer
composed of N403A.The output end of N403A(SEARCH)is connected to the pin 28 of
CPU. This control signal isthe search and detect signal: when it is lowlevel, it enters the
search mode; whenit is high level, it stops searching. Its worksas follows:
3.1.1 When thisunit is getting started, theA&B control signals from the pins 38&39 in
the domination ofthe CPU's inter program are added to the inputselect circuit to
search circularly once.When there are no signals in these four inputconnectors, the
VCD mode stopsautomatically. When there are signals in one of the fourconnectors,
AC signals willappear in all channels of the input N402. These ACsignals are
amplified by N403Band rectified and filtered by VD434 and C481 tobecome DC
signals. Atthis time, the opposite-phase voltage of N403A is0.01V. When this DC
voltage surpasses 0.01V, the output end of N403B sends out ahigh level (SEARCH)
close to positivepower supply voltage (A+6V) which reaches the pin 28of CPU. CPU
keeps searching inthe connector in which there are input signals andthe unit will play
normally.
1.2.2 When pressthe SEARCH on the front panel,CPU sends out A&B control
signals again tostart searching. Meanwhile, the pin 27 (EX) sends outa high level
which makes V446inductive. The emitter of V446 sends out a high level whichpasses
through R498 whichmakes the opposite-phase voltage of N403Ato be 0.4V. That is
to say, if you want to stopsearching of CPU, the gained voltage after the inputsignals
are rectified andfiltered must exceed 0.4V. This voltage is higher than 0.01V when
this unit isgetting started in order to avoid that the CPUreceives signals mistakenly
and stops searchingdue to the large external interference signals. If theinput signals'
amplitude is nothigh enough, CPU will continue searching. When the amplitudeis
high enough, N403Asends out high level to the pin 28 to stop searching. The pin 27
(EX) will becomelow level again and the opposite-phase voltage of N403Awill also
returns back to0.01V. The whole searching process isfinished.
¢óTHEEXP L ANA TI ONF ORKE YCOMPONENT SCPUI CW7 8 E5 4

- 4 -- 23 -
3.2 Spectrum SamplingAmplification Circuit:The routes carrying the five-channel
signals sent fromthe IC N402 are connected to the sampling resistors R494, R495,
R496, R565 andR566 respetively.(The SW channelsends out the signals directly.) After
being mixed bythese resistors, the signals reach N406Ato be amplified. The incurred
spectrum analyzing signalsource is sent to the front panel circuit.
4. Control Circuit.
The control circuitof this player is divided into CPU Circuit, Front Panel Control and
Display Circuit andSpectrum Analyzing Circuit.
4.1 CPU Circuit
N422 (AT89C540) is this unit's CPU whichsends all commandsto the command-
controlled circuits toperform all control functions. It incorporates +5V power supply and
its pin 40is the power supply pin. The 12M crystal oscillator provides the work clock for
itself. The pin 9 isthe restoration pin. When this unit is getting started, +5V passes
VD409 to reachthe positive pole of C531. Because of the C531's charging, its negative
end sends outan instantaneous high level which passes through R686 to reach the pin
9 of N422.The pin 9 of N422 restores the low level mode with the end ofcharging. This
restoration circuit's styleis the high level restoration to keep in low level. You can also
refer to thecircuit diagram for other command instructions.
The static informationsuch as the power-on logo and on screen displays when this unit
is working isstored in the CPU's static memory. N421 isa power-off-mode memory which
can record theworking information when this unit is turned off and call back these
information when thisunit is turned on next time. Therefore, you need not to readjust the
unit every timeyou turn it on. Furthermore, the sound field modes that you setare also
stored in N421,which can be called back when needed.
4.2 Front panelcontrol and display circuit
This circuit incorporatesan exclusive IC N901 (UPD16311). Its pins10, 11, 12 and13
are connected tothe press scan matrix which receives the control commands from the
user and processthem into two-line outputs: One line reaches to the VFD to displaythe
working modes, anotherline passes pins 5, 6, 8 and 9 to CPU to finishthe control
functions.
N902 is theremote control sensor. It convert the infrared signals received to electric
signal and thensend it to the pin 13 of CPU to finish the remotecontrol function.
RP901 and RP905comprise a digital pulse potentiometer. When rotating it, a series of
digital pulse willbe sent out and added to the pins 23, 24, 25 and26 to bedetect and
processed to finishthe control functions. RP901 finishes the master volume adjustment
and RP905 finishesmulti-function adjustment.
ToEncoder(Master)
R621 680K
R618
100K
R619
1K
R626
1K
R622 1K
R627 5.6K
R623 10k
R625
2.2K
R620
10K
+12V -12V
R613
10K
R608
10K
R603
10K
R598
10K
R593
10K
C524
223
C515
272
C518
682
C521
683
C527
154
R596 1K
R597
10K
R601
1K
R602
10K
R594
5.6K
R599
5.6K
R604
5.6K
R609
5.6K
R614
5.6K
R595
82K
R600
82K
R610
82K
R615
82K
R606 1K
R607
10K
R611 1K
R612
10K
R616
1K
R617
10K
C516 272
C519
682
C525
223
C523
2.2U C526 2.2U
C529
2.2u C520
2.2U
C517
2.2U
C522
683
R605
82K
12 13
14
N417D
LM324
12 13
14
N418D LM324
3 2
1
411
N418A
LM324
10
9
8
N417C
LM324
C528
154
-12V
35Hz
100Hz
300Hz
1KHz
3KHz
10
9
8
N418C LM324
VD446
1N4148
VD445
1N4148 VD444 1N4148 VD443 1N4148
VD442 1N4148
C507 10u/16V
+12V
R588
10K
R583
10K
C509
152
C512
681
R586 1K
R587
10K
R591 1K
R592
10K
R584
5.6K
R589
5.6K
R58582K
R59082K
C510
152
C513 681
C514
2.2U
C511
2.2U
3 2
1
411
N417A LM324
10KHz
16KHz
5 6
7
N418B
LM324
VD441 1N4148
VD440
1N4148
R580
1K
C508 10u/16V
X4
1
X6
2
XCOM
3
X7
4
X5
5
INH
6
VEE
7
VSS
8C(2) 9
B(1) 10 A(0) 11
X3 12 X0 13 X1 14 X2 15
VDD 16
N416
4051
X4
1
X6
2
XCOM
3
X7
4
X5
5
INH
6
VEE
7
VSS
8C(2) 9
B(1) 10 A(0) 11
X3 12 X0 13 X1 14 X2 15
VDD 16
N419 4051
R581
10K
R582
470K
5 6
7
N417B
LM324
-12V +12V
S-6.2V
3 2
1
84
N420A
4558
5 6
7
N420B
4558
VD447 3.3V
+12V
V435
2N5551
V437 2N5551
EC
B
V436
2N5401
R628
4.7K
R572
180k
R571
75k
R576
4.3k
R579
10k
R5771.5k R57427k
R578
2.2k
R624
10K
VD449 1N4148
VD450 1N4148
D+5V
VD448 1N4148
D+5V
R573 470k
-12V
+12V
S+6.8V
DIS1A DIS1B DIS1C
DIS2A DIS2B DIS2C
C530 104
1 2 3 4 5 6 7 8 9
10
11
12 13 14 15 16 17 18 19 20
25 40 39 38 37 36 35 34 33 32 31 30 29
28
27 26 24 23 22 21
Vcc
P00(AD0) P01(AD1) P02(AD2) P03(AD3) P04(AD4) P05(AD5) P06(AD6)
P07AD7)
EA/Vpp
ALE
PSEN
P20(A8) P21(A9)
P22(A10) P23(A11) P24(A12) P25(A13) P26(A14) P27(A15)
P10(T2) P11(T2)
P12 P13 P14 P15 P16 P17
RST P30(RXD) P31(TXD) P32(INT0) P33(INT1) P34(T0) P35(T1) P36(WR) P37(RD) XTAL2 XTAL1
GND
N422
AT89C54
DISPLAY
1 2 3 4 5 6 7 8 9
XS4 8PIN
A SDA LATCH B SCK CLK DATA
To CD4052
To M62446
RelayControl
REMOTE CLK DATA STB
A1 B1 A2 B2
To uPD16311
ToEncoder1(MasterVOL.)
o2Jog
C661
20P
C662
20P
G401 12M
L406 100uH
D+5V
534
104
R575
1k
R570 1k
VD438
6.8V
VD439 6.8V
C506
47u/16V
C505
47u/16V
S+6.8V
S-6.8V
1
2
3
4
5
6
7
8
9
RR901 8*4.7K
C535
47u/16V
R629 10k
C531 10u/16V
A0
1
A1
2
A2
3
VSS
4SDA 5
SCL 6
TEST 7
VDD 8
N421 24C02
SCK
D+5V
SDA
SEL SEARCH
To CD4053
To 24C02
E.OE
K-MUT
R687 1k
R688 2.2k
VD409 1N4004
VD410
4.7V
C665
47u/16V
P-RST
SEL1 R-T
EX
To CD4053(N411) RelayTest(Y402)
ExchangeSearchLevel
MICMutting
R690 4.7k
R689 2.2k
+A6V
R685 4.7k
R691 4.7k
R680 4.7k D+5V
R686 1k
C668
47u/16V
C669 47u/16V
+12V +12V
-12V -12V

- 5 - - 22 -
4.3 Spectrum analyzingcircuit (The flowchart is shown an Figure 2)
N416
CD4051
Automatic
Spectrum
Gain
Adjustment
}
CPU
DISPLAY +
-
.N419
CD4051
Frequency
Selected
7-band Filter
35HZ
100HZ
300HZ
1KHZ
3KHZ
10KHZ
16KHZ
}
CPU
V437 CPU Pin 12
V435 CPU Pin 1
V436
+5V .
+
-
-
N417B
N420B
N420A
A/D Conversion
(Figure 2)
3
3
4.3.1 Automaticspectrum gain adjustment circuit: In order to avoid that the display
amplitude is toonarrow when the input signals are too weak or the whole display
appears when theinput signals are too strong, this unit incorporates an automatic
spectrum gain adjustmentcircuit which employs a single channel 1-out-of-8 electronic
analog switch N416(CD4051). Its real value table is below. Its working principle is
that it changesthe opposite-phase ground resistor's resistance value of the
operational amplifier N417Bto change the gain times.
We have mentioned before thatthe spectrum analyzing signal source is sent to the
operational amplifier N417B'sin-phase input terminal to be amplified. Its amplified
times depend onthe resistance value of the resistor connected through the electronic
switch N416 tothe opposite-phase terminal. When the master volume is too big, the
CPU will automaticallyadd the ground resistor's resistance value to reduce the am
plification times. Whenthe master volume is too small, the CPU will automatically
reduce the groundresistor's resistance value to increase the amplification times.
CD4051Real Value Table
A
B
X0 X1 X2 X3
0
00
0
1
1
1
1
CD4051 Real Value Table
0
0
X4 X5 X6 X7
1
01
1
0
1
C00001111
V405 2N5551
-36V
VD401 1N4148
+36V
V401
2N5551
V409
2N5401 V410
2N5401
V412
A1694
V406 2N5551
V402 2N5551
V411
C4467
V403
2N5551
V404 2N5401
R403
1K
C405
10u/16V
R404
47K C406
221
R405
2.7K
R407
47
R406 2.7K
R419
33K
R410
1K
C407
100U/16V
R408
47
R409 620
R411 33K
R412
1k
R413
200
C408 33
R416
200
VD402 1N4148
V408
2N5551
V407
2N5551
R418
10
R417 10
R423
10
R422 10
R421
100/0.25W
R420
100/0.25W
R414
4.7K
R415 2K
C409
104
C403
100U/50V
C402
104
C404 104
C401
100u/50V
V417 2N5551
-36V
VD405 1N4148
+36V
V413
2N5551
V421
2N5401 V422
2N5401
V424
A1694
V418
2N5551
V414 2N5551
V423
C4467
V415
2N5551
V416 2N5401
R430
1K
C415
10u/16V
R431
47K C416
221
R432
2.7K
R434
47
R433 2.7K
R446
33K
R437
1K
C417
100U/16V
R435 47
R436 620
R438 33K
R439
1k
R440
200
C418 33
R443
200
VD406 1N4148
V420
2N5551
V419
2N5551
R445
10
R444 10
R450
10
R449 10
R448 100/0.25W R447 100/0.25W
R441
4.7K
R442
2K
C419
104
C413
100U/50V
C412 104
C414
104
C411
100u/50V
V429 C9014
V428
C9014
V432
C8050
V426
C9014
R492 220/3W
R491 220/3W
R476
2.7k
R425
0.25/3W
R424
0.25/3W
R470
3.9k
R472
2.7k
R473
4.7/1W
R471
3.9k
R484
100k
C436
104
VD415
1N4148
VD416 1N4148
VD420
1N4148
R478
47k
R480
10k R481
10k
R482
47k
C440 220u/25V
C439
220u/25V
C449 6800u/50V
C450 470u/25V C452
47u/16V
C451
470u/25V
C447 6800u/50V
FL404 T6.3A/250V~ FL403 T6.3A/250V~
+16V
V430
C9015
C435 1u/16V
C441
47u/25V
C445 224 C444 224
R485
10k
V427 C9014
R474
3.9k
R477
4.7/1W
R475
3.9k
C438
104
C437 1u/16V
V433
S8550
VD429
12V
R493 2k2
C453
47u/16V
C454
47u/16V
+12V -12V
R452
0.25/3W
R451 0.25/3W
R479
1k
VD425 1N5404 VD426 1N5404
VD427 1N5404 VD428 1N5404
VD418 6.8V
R486 10k
VD417 1N4148
L401
0.7uH
L402
0.7uH
R
SPEAKER
L
SPEAKER
A B
C D
L403 1.8mH C457
~275V104
FUSE
T3.15AL250V
~220V
50Hz 1
2
XS1 2PIN
1 2
XP1 2PIN
1 2
XS2 2PIN
TOsaitchpweroobard
1 2 3 4 5 6
XS3
6P1N
FL402 T4A/250V~ FL401 T4A/250V~
VD421 RL254
VD422 RL254 VD423 RL254 VD424 RL254
C442
2200u/25V
C443 2200u/25V
V431
9014
R483 10k
3
2
1IN
GND
OUT
N412
7812
E.O.E
VD419 1N4148R487
10K
9
10 11 12
13
1 5 2 6 3 7 4 8
14
Y402
RE-402DM
-16v
+36V
-36V
R489 560/1W R490 560/1W
53
1 2
4
N413 TDA2030
R457 680
R458 15k
C422
22u/16v
+16V
-16V
R459 10
C423 104
C
53
1 2
4
N414 TDA2030
R461 680
R462
15k
C427
22u/16V
R463 10
C428
104
SL
53
1 2
4
N415 TDA2030
R465 680
R466 15k
C432
22u/16V
R467 10
C433
104
SR
R488
10
SL-INC-IN SR-IN
C426 10u/25V
C424
10u/25V C460
103
C434 103
C446
104
C448
104
L R
C455 104 C456 104
R692
220/0.5W
R693 220/0.5W R694 220/0.5W R695 220/0.5W
R453
2.2k R454
2.2k R455
2.2k
C430
151
C431
151
C429
151
Y401
GSADC12V
R401
10k
R402 470k
R426 10k R427
470k
R428 4.7k R429
10k
V440
2N5401
V442
S8050
V441 S8050
MUT1
R682 47k R683
47k R684
47k
V443
9014
R681 10
V445 C8050
V444 9014
VD411 6.8V
MUT2 R-T
C-OUT SL-OUT SR-OUT
C-OUT SR-OUT SL-OUT
VD412
1N4148
R497
1k

- 6 -- 21 -
4.3.2 Frequency SelectedCircuit
The signal amplifiedby the N417B is coupled by C508 and then sent to the7-band
filter composed ofthe operational amplifiers. Setting its feedback capacitor's capacity
can define thecorresponding frequency amplitude. The frequency value marked on
their output pointsis the frequency band's central frequency. There's a half-wave
rectifying circuit connectedto the every band filter's output end. The circuit will rectify
the amplifiedAC signals into the DC voltage. The circuit is mainly performing the
frequency sampling functionwhich can show the amplitude of every frequency of the
whole audio signalsthrough the DC voltage. If the low frequency of the current audio
signals is strong,the DC voltage of the 35Hz and 100Hz band filter is higher. If the
high frequency isstrong, the DC voltage of the 10K and 16K band filter ishigher. The
output end ofthese seven band filters is connected to seven input terminals of the
electronic switch N419(CD4051). CPU will send commands to make this electronic
switch select thefrequencies circularly (Refer to the above real value table). The
output terminal ofthe pin 3 of N419 will send out a series of voltagerepresenting the
corresponding frequency's amplitude.(SeeFigure 3)
35HZ 100HZ
300HZ
1KHZ
3KHZ
10KHZ
16KHZ
35HZ
T
V
Switch interval
Frequency selected circularly period
Note:the diagram's
voltage amplitude
is not definite
(Figure 3)
SCHEMATIC DIAGRAM OF THE MAINAMP BOARD
OUT4
1
OUT3
2
OUT2
3
OUT1
4
AVDD
5
SWIN
6
GNDS
7
SRIN
8
SLIN
9
GNDC
10
CIN
11
GNDR
12
RIN
13
GNDL
14
LIN
15
BYPASR
16
BYPASL
17
LTRE
18
LBASS3
19
LBASS2
20
LBASS1
21 RBASS1 22
RBASS2 23 RBASS3 24
RTRE 25
CR2 26 CR1 27
CL2 28 CL1 29
AVSS 30 LOUT 31
ROUT 32 COUT 33
SLOUT 34
SROUT 35
SWOUT 36
AGND 37 DGND 38
LATCH 39
DATA 40
CLK 41
DVDD 42
N402
M62446
D+12V
C469
4.7u/16V
C470
4.7u/16V
C471
4.7u/16V
C472
4.7u/16V
C473
4.7u/16V
C4744.7u/16V
C475
4.7u/16V
C476
4.7u/16V
C477
822
C478
153
C479
334
C468 104
A+6V
R536
100k R537
100k
R549 150
C497
100u/16V
C495
104
R548
100
R547
100
R546100
VD436
5.1V
C494 4.7u/16V C493 4.7u/16V C492 4.7u/16V C491 4.7u/16V C490 4.7u/16V C489 4.7u/16V
C486
4.7u/16V
C485
4.7u/16V
C484 822
C483 153 C482 334
C487 104
TAPER
VCD L
CD R
VCD R
CD L
5.1CHR
5.1CHL
TAPEL
X0
12
X1
14
X2
15
X3
11
Y0
1
Y1
5
Y2
2
Y3
4
INH 6
A10 B9
VEE
7
X13 Y3
168
N401
CD4052
C464 47u/16V
R530
470
VD432
6.8V
VD431
6.8V R529
470
C462
47u/16V
-12V
+12V
R531
1k
R532
1k
REC R
REC L
C465 10u/16V C466 10u/16V
R527 47k R528
47k
R5111k R514
1k
R515
1k
R5181k R522
1k
R5191k
R5231k
R526
1k
C
SW
SL
SR
R503150 R5061k
R5071k R5101k
5 6
7
N403B
4558
3 2
1
84
N403A
4558
SW
LINEOUT
R
L
R533 100k
R534100k
A+6V
A-6V
R538
1.5M
C480
101
VD434
1N4148
C481
4.7u/16V
R539 150
R540
10k
R542 100k R541 220
R501
150
R502
47k
5 6
7
N405B
4558
3 2
1
84
N404A 4558
5 6
7
N404B
4558
3 2
1
84
N405A
4558
R554 10k
R557 10k
R556
10k
R553 10k
R559 22k R562 22k
C500
101
C498
101
+12V +12V
-12V -12V
R563
10k
R564 22k R560
10k
R561 22k
C503
33P
C502
33P
SR-IN SL-IN C-IN
R L
R543
1k R544
4.7k
SEARCH R565
47k
R566
47k
3 2
1
84
N406A
4558
-12V
+12V
R567
22k C504
101
DISPLAY
C501
103
CLK DATA LATCH
A B
R50447k R50547k R50847k R50947k R52447k R52547k R51247k R51347k R51647k R51747k R520
47k
R52147k
L404
100uH
D+5V L405
WBC
C496 47u/16V
D+5V
-12V
MIC
ToVFDBoard
R555 47k
R558 47k
R550 47k
R551 47k
R552 47k
C461 104
C463 104
R675 100k
R676 100k
R677 100k R678 100k
R496 47k R495 47k R494 47k
R635 100k
R636 100k
C639 221
C538 4.7u/16V
R637 100k
R638 100k C641
221
C640 4.7u/16V
5 6
7
N407B
4558
5 6
7
N408B
4558
3 2
1
84
N407A
4558
3 2
1
84
N408A 4558
+12V
-12V
-12V +12V
R640 56k R642
56k
R639
56k
R643
56k
R644
75k
R645
75k
R641
47k
C642
101
C643 101
X0
12
X1
13
Y0
2
Y1
1
Z0
5
Z1
3
INH
6
A
11
B
10
C
9VEE 7
Z4
Y15 X14
VCC 16
Vss 8
N410 CD4053C
X0
12
X1
13
Y0
2
Y1
1
Z0
5
Z1
3
INH
6
A
11
B
10
C
9VEE 7
Z4
Y15 X14
VCC 16
Vss 8
N411
CD4053C
R664
100k
R665 100k R663
100k
R666 100k
S-C S-S
R657
1k
R655
1k
D-SW
S-C S-S
R667
1k
R668
1k
D-SW
5 6
7
N406B 4558
C646
682
R659
75k
R660 47k C647
103
R661
47k
C648 10u/16V
R662 100k
V439
2N5401
R545
47
C488
47u/16V
C467 47u/16V
R535
47
A+6V
A-6V
A-6V
A+6V
A+6V A-6V
A-6VSEL
SEL
R L
C420 47u/16V C421 47u/16V
S-SW
R679
680k
+12V
R658
1k
SEL1
C539
10u/16V
V446
9014
V4382N5551
A+6V
R499
4.7k
R498 2.2k
EX
C666
47u/16V
C667 47u/16V
R500 22k
MUT1
C499 103
MUT2
1 2 3 4 5 6 7 8
XS5 8PIN
MS
R568
10k

- 7 -
4.3.3 A/Dconversion and display output circuit: The output voltage from the pin 3 of
N419 passes throughN420B where it is amplified and sent to the opposite-phase
terminal of N420A.N420A composes a voltage comparer. We'll discuss its detailed
working process accordingthe voltage comparing characteristics (When the in-phase
end's voltage ishigher than that of the opposite-phase end, the output is the positive
power. Whenthe in-phase end's voltage is lower than that of the opposite-phase end,
the output isthe negative power.) and the figure 4.
When the opposite-phaseend has a DC voltage representing 35Hz signal amplitude,
the output ofN420A is a low level close to the negative power supply. At the same time,
+5V provides conditionsfor V436 to be conductive and a high level from the collector
of V436 chargesC530. The positive end's voltage of C530 (i.e. the in-phase end of
N420A) is increasinggradually. When the voltage reach that of the opposite-phase
end, the voltagecomparer will overturn. Therefore, N420 sends out a high level close
to the positivepower supply voltage. When the comparer overturns, CPU will
terminate the 35Hzlevel selection and switch to the next frequency 100Hz. During the
switch interval, aninstantaneous high level from the pin 1 of CPU makes V435
conductive and thevoltage of C530 will be released. The in-phase end of N420Awill
be charged from0 level to 100Hz. When 100Hz charge is finished, it will switchto the
next frequency. The process is circulated under CPU's control.The charging time from
the 0 levelto overturn represent current frequency's signal amplitude. The amplitude
is large, timeis longer; the amplitude is small, time is shorter. We can conclude from
the above circuitworking process: An analog series of DC level which has concrete
voltage value originallybecomes two mode of 0 and 1. Its time period represents the
digital pulse ofthe original information. That is to say, it finishesthe analog-to-digital
conversion process. The digital pulsesent out from the output terminal of N420A
reaches the pin12 of CPU after opposite-phased by V437. And then CPU processes
it and sendsit to front panel display IC N901 which will make dynamic spectrum
display on thedisplay. As a matter of fact, every frequency is displayed sequentially.
However, whatwe see on the display screen is the working process all thespectrums
are displayed simultaneouslydue to every frequency display circulate very quickly.
V
T
35HZ
100HZ
Switch time interval
V
T
35HZ 100HZ
Charge time Charge time
High level
discharge
(Figure 4)
- 20 -
127 CONNECTION
CORDS ¦µ
0.6 SHAPED 10mm
W4,W6,W7,W9,W13,W17,W23,W25,W29,W31,W32,W35,
W40,W41,W44~W47,W54,W55,W62,W65,W80,W90,W97,
W103,W111,W112,W117,W121,W122,W133,W137,W142,
W143,W154,W163,W167,W168,W174,W177,W178,W180,
W181,W185,W186,W190,W207,W208,W209,W37
128 CONNECTION
CORDS ¦µ
0.6 SHAPED 12.5mm
W57,W60,W67,W68,W70,W71,W77,W93,W104,
W120,W123,W124,W128,W130,W131,W144,W145,W148,
W204
129 CONNECTION
CORDS ¦µ
0.6 SHAPED 15mm W83,W85,W86,W107,W115,W126,W129,W146,W147,
W169~W173,W175,W176,W182,W183,W191,W201,W82
130 CONNECTION
CORDS ¦µ
0.6 SHAPED 20mm W33,W34,W48,W51,W114,W132,W134,W141,W166,W192,
W196,W200,W203
131 CABLE 20# 60mm BLACK WITH CHIP
SOLDER GROUND WIRE
132 CABLE 18# 70mm BLACK XJ1~XJ2
CABLE 22££
80mm BLACK XJ1~XJ2
133 FUSE TUBE T6.3AL 250V FL403,FL404
134 FUSE TUBE T4AL 250V FL405,FL401,FL402
135 FUSE HOLDER BLX-2 FL405
136 RADIATOR
BOARD 30×16×16 AB207 SRQ401
137 LARGE
RADIATOR 267.5×91×70 AV210 CONNECTED TO THE MAIN AMPLIFICATION BOARD
138 FUSE HOLDER 0FL401~FL404
139 SMALL CHIP AB207 FIX TRIODE
140 ANGLE
ALUMINUM 90×23.2×30 AV210 POWER IC / LARGE RADIATOR
141 TAPPING
SCREW BT 3×8 BLACK 2 FOR RADIATOR BOARD/MAIN AMPLIFICATION BOARD,
1 FOR N412/RADIATOR BOARD
142 TAPPING
SCREW PB 3×12H COLOR ZINC 2 FOR SMALL CHIP/LARGE RADIATOR, 5 FOR ANGLE
ALUMINUM/LARGE RADIATOR
143 TAPPING
SCREW PWT 3×8×8 COLOR ZINC 1 FOR MAIN AMPLIFICATION/RADIATOR, GROUNDED
144 TAPPING
SCREW BT 3×8H COLOR ZINC 1 FOR MAIN AMPLIFICATION/RADIATOR, 3 FOR ANGLE
ALUMINUM/POWER IC
145 MACHINE
SCREW PWM 3×16×8 COLOR ZINC 4 FOR POWER TUBE/LARGE RADIATOR
146 SCREW NUT M3
147 SCREW
SPACER ¦µ
3×7.2×0.5
148 SPRING
SPACER ¦µ
3
149 INSULATION
RING ¦µ
3×6×3 N413~N415
150 MICA SPACER 18×
13× 0. 1
151 MICA SPACER 22×
19× 0. 1 4 FOR POWER TUBE / RADIATOR

- 8 -
5. Microphone Circuit
The microphone circuitis divided into two parts: The Front Process Section and Echo
Process Section
5.1 Front SectionCircuit: Mainly performing volume adjusting/amplifying/modifying
function. The flow chart isshown as Figure 5.
MIC1
MIC2
V901
Following
Amplification
N904B
Voiced
Circuit
Echo
Process
Section
RP901
RP902
N903A
N903B
N904A
(Figure 5)
- 19 -
92
VOLTAGE
REGULATOR
DIODE
5.1V 1/2W VD436,VD411
93
VOLTAGE
REGULATOR
DIODE
12V 1/2W VD429
94
VOLTAGE
REGULATOR
DIODE
6.8V 1/2W VD431,VD432,VD438,VD439
95 TRIODE 2N5401 V404,V409,V410,V416,V421,V422,V440,V436,V439
96 TRIODE 2N5551 V401,V402,V403,V405~V408,V413,V414,V415,V417~V420,
V435,V437,V438
97 TRIODE 8050C V432,V445,V441,V442
99 TRIODE 9014C V426~V429,V431,V443,V444,V446
100 TRIODE 9015C V430
TRIODE S8550D V433
101 TRIODE KB688O V412,V424
TRIODE KB688Y V412,V424
102 TRIODE KD718O V411,V423
TRIODE KD718Y V411,V423
103 IC LM324N DIP N417,N418
104 IC NJM4558D DIP N403~N408,N420
IC 4558C DIP N403~N408,N420
105 IC L7812CV GOLD-SEALED TO-
220 N412
IC LM7812 GOLD-SEALED TO-
220 N412
106 IC CD4051 DIP N416,N419
107 IC CD4053BCN DIP N410,N411
108 IC CD4052BCN DIP N401
109 IC M62446FP SOP N402
110 IC 24C02 DIP N421
111 IC LM1875T T05B N413,N414,N415
112 SOFTWARE
PROGRAM CPU CPU-AV210(RU)-0 N422
113 CRYSTAL
OSCILLATOR 12.00MHz 49-U G601
114 RELAY JH1806-012-(3H1£«
1Z1) DC12V Y402
115 RELAY JH4237-012-2H DC12V Y401
116 PCB 4210-3
117 TERMINAL
SOCKET AV6-8.4-53 XC401
118 TERMINAL
SOCKET AV8-8.4-62 XC402
119 TERMINAL
SOCKET AV1-8.4-5 BLACK XC403
120 SOCKET 8 PINS 2.5mm XS5
121 SOCKET 9 PINS 2.5mm XS4
122 SOCKET 2 PINS 7.92mm XS1,XS2
123 SOCKET 6 PINS 3.96mm XS3
124 CONNECTOR'S
SOCKET WP4-10A XL401
125 CONNECTOR'S
SOCKET WP6-10A XL402
126 CONNECTION
CORDS ¦µ
0.6 SHAPED 7.5mm
W1~W3,W5,W8,W10~W12,W14~W16,W18~W22,W24,
W26~W28,W30,W36,W38,W39,W42,W43,W49,W50,W52,
W53,W56,W58,W59,W61,W63,W64,W66,W69,W72~W76,
W78,W79,W81,W84,W87~W89,W91,W92,W94~W96,
W98~W102,W105,W106,W108~W110,W113,W116,
W118,W119,W125,W127,W135,W136,W138~W140,
W149~W153,W155~W162,W164,W165,W179,W184,
W187~W189,W193~W195,W197~W199,W205,W206