Akai AT 2200 2200 L Service Manual

Page 11

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COMPOSWE srswzocrsk" F c c: m:
SAGNAL

mm CHANNEL smut

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sue CHANNEL 5mm».

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l
l 19ka
l
r
1

v2 38m Va 76ka
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Dwmsw mvmzn

39on

[3
DiCODER E

Fig. 12 MPX IC Function

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sun CHANNEL SIGNAL 3 V LEFY cxmnst SlGML

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fi-L

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19m Suarcsnmzno-w mm MEL SIGNAL

Fig. 13 Multiplex Decoder

The 38 kHz sub carrier composited with the sub
channel signal of which the carrier part was removed
when sub channel signal and sub carner passed R1 R2
produces the regular AM wave. Then, because this
envelop is detected by mutually reverse polarity
connected diodes D1 and D2, L-R signal is emitted
at point @ and R-L signal at point .1

Also, because main channel signal (L+R) is supplied
to R3, R4 center point, ® ® point voltage is added
and subtracted and becomes

(L+R) + (L-R) = 2L (left channel)
(L+R) + (R-L) = 2R (right channel)

The level of the main channel signal (L+R) can be
adjusted by means of variable resistor VR(VR1) for
optimum separation.

Thus, the function of actually employed PLL IC
LA-3350 is 3 shown in Fig 141

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wuro- mm: ,c _ W m m 7 35m 1

3m.

Fig. 14 LA-3350 Function System Diagram

Page 16

1) FM Tuner Section adjustment (Refer to Fig. 17)
Please refer to model AT-2200 FM Tuner Section adjustment Chart-l.

2) LW Tuner Section adjustment (Refer to Fig. 17)

StepTTTAEsEeTAc Item TTT TAdjuTstmentTPartTi TTT TileletT TTTTTTTTTTTQnEs-TT
7T am: e
T g T T3(GRN) LW Error: T Set Selector to LW 160 kHz
T 1 Frequency
T T Coverage T OSC Coil T Within 2% T optional input
T T Bar antenna T T T
T 2 T 10]?ng T LW mfl T Mammum T X60 kHz optional input T
T Sensrtivrty T5 (YLW,BLK) output T
T T4(WHT) T T
TTTTTTT TfigfianTge TT T T T T TTTTTTTTTTTTTTTTT TTTTTTTT
. T T
T 3 Frequency VC2o LW OSC .Error T 340 kHz optional input T
T Coverage trimmer _ Within 2% T T
_rs7 , _ i ,7 77 w i.___* , _*___-l
T 4 High Raw T 31wa T Maximum T 340 kHz optional input T
Sensitivity T antenna trimmer output T
Chart-3
3) MW Tuner Section adjustment (Refer to Fig. 17)
TSteTpTTT TAdeTustment Item T AdeuaneEPaTrt ReTsult TTT Remarks T
Pie»; T» , 7:77 Tieefieg~&-T
w an e T T
T 1 FTequenfy T T2(RED) MW Error: T Set Selector to MW 520 kHz T
T Coverage OSC Coil T Within 2% T optional input T
T T Low Range T Bar antTennaT T Maximum TT T
2 T Sensitivity MW Coil T output T 520 kHz optional input T
Tlugghim; T* * * A T ' u
g
T 3 T Frequency T VCZa MW WTEITOT'T 1,400 kHz optional input T
Coverage T OSC trimmer ithin 2% T
T 4 T TI-Tligh Range VCla MWT MaximuinT TTTT
T T Sensitivity T antenna trimmer T 7 output TT 1 400 kHz optional input T

Chan-4

14