Toshiba SA 504 Service Manual

Page 2

SA~504

14.
15.

TABLE OF CONTENTS

Operating Controls ................................................. 3
11 Front View ................................................ 3
1-2 Rear View ................................................. 3
Disassemblies ...................................................... 4
2-1, 2-5 Cabinet Removal ............................................ 4
2-2, 2-4 Bottom Cover Removal 4
2-3, 2-6 Front Panel Removal 4
Parts Locations .................................................... 5
3-1 Chassis Bottom View ........................................... 5
3-2 Chassis Top View .............................................. 6
3-3 Voltage Adjustment ............................................ 6
Technical Points 7
Adjustments ....................................................... 10
5-1 AM Tuner Adjustment 10
52 FM Tuner Adjustment 11
5-3 FM MPX Adjustment 13
Trouble Shooting Hints ............................................. 14
Level Diagram ..................................................... 15
Transistor Base Diagrams ....... 15
Integrated CirCUit Base Diagram 16
Dial Stringing Diagram .............................................. 16
Cabinet Exploded View ............................................. 17
Schematic Diagram ................................................ 19
Printed Circuit Diagrams ............................................ 21
FM Front-End Circuit Board (CCT-RF-CO3) -> (CCT-RF-COS) ................... 21
IF Limit Circuit Board (CCT-lF-COZ) 22
FM Multi Circuit Board (CCT»MPX-C02) 23
Equalizer Circuit Board ICCT-AF-CDQ) 24
Driver Circuit Board (CCT-AF-CO4) 25
Loudness Circuit Board (CCT-SWl-C01) 26
Filter Circuit Board

Low (CCT-SWl-C03) ............................................ 26

High (CCT-SWl-C02) ............................................ 26
Muting Circuit Board (CCT-SWl»CD5) .................................. 27
Tape Monitor Circuit Board (CCT-SW l-COB) 27
Phase Invert Circuit Board (CCT-AF-C13) 28
Filter Circuit Board (CCT-FlLT-C01) ................................... 28
Matrix Circuit Board (CCT»AF-C10) .................................... 29
Tune Circuit Board (CCT-AF-C14) ..................................... 31
Power Supply Circuit Board (CCT-SPLY-C06) ............................ 33

Packing
Parts List

Page 8

a 11th

can be reproduced in the four channel fashion with
the builtrin MATRIX Decoder.

6. SO

Fig. 1 shows signal components LT and RT recorded
on 80. record disc. Decoder shown in Fig. 1-b changes
composite two»channel signals into four-channel
stereo signals FL, RL, FR and RR. Such a decoder
produces sound field extended in right and left
directions but not so extended in front and rear
directions.

To improve front and rear channel separation, 50
decoder mixes LT and RT signals in proper propor-
tion as shown in Fig. 2.

14dB between front left and front right
channels.
*6 dB between front and rear channels.
*SdB between rear left and rear
channels.

Note:

right

Matrix circuits shown in Fig. 3-a, 3-b, 13-0 and 3-d
mixes LT+0.2RT, RT+0.2LT, LT-0.4RT and
RT >0.4LT signals respectively. TR04, TROS, TROG
and TROS amplifies signals attenuated by matrix
circuits.

Circuit shown in Fig. 4a has a phase characteristic
in Fig. 4-b. Low Frequency signal ontput is almost
the same phase as the input. As frequency becomes
higher. output phase negatively shifts. Combination
of such two circuits, one shifts 90 degrees at F1 and
the other 90 degrees at F2, makes 90 degrees phase
difference in some range. This circuit is called
phase-shifter.

RL and RR' signals are mixed through phase-shifter
in Fig. 5a and 5-b and amplified by TR09 and TR07
respectively to set the levels.

7. R-MTX

R-MTX circuit mixes front-left and front-right signals
in the same proportion as $0 to improve front and
rear channel separation.

Rear channel signals are mixed in the proportions
such as RR = R - 0.4L and RL = L - 0.4R as shown
in Fig. 6.

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u fir

80°~100° phase difference at approx 100~760 Hz

Fig. 2

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i

mum:

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as

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mom;

TROl TROl
(:07
em
TR02 TR02
W20
Cw mo C03 P22
TRO4
(a) (b)
TRO' C05 W5 TROI
C07
' If
TROB " TR05
.4
C14 c1}
TR02 ce TR02
cos me
me
(o) (d)
Fig. 3
c
R
90 phase dlflerence
(a) (b)

Fig. 4