Technics SU-A909 User manual

Table Of Contents
COVER
1 Note
2 Location of Controls
3 To Supply Power Source
3.1 Power Supply to Main
Circuit
3.2 Operation Check
4 Operation Checks and
Component
ReplacementProcedures
5 Type Illustration of ICs,
Transistors and Diodes
6 Schematic Diagram
6.1 Schematic Diagram
Notes
6.2 Schematic Diagram
7 Printed Circuit Board
Diagram
8 Block Diagram
9 Wiring Connection
Diagram
10 Measurements and
Adjustments
10.1 Measurement
instruments and Special tools
10.2 Output Voltage
Adjustment
11 Terminal Function of
ICs
11.1 IC701
(M38503M2404F) : Micro
Computer
12 Replacement Parts List
13 Cabinet Parts Location
14 Packaging
Service Manual
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AD9907176C2
Control Amplifier
●SU-C909U
Colour
(K)..........Black Type
Area
(E)..........Europe and Russia.
PV
PV

© 1999 Matsushita Electric Industrial Co., Ltd. All rights reserved. Unauthorized copying and distribution is a violation of law.
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Table Of Contents
COVER
1 Note
2 Location of Controls
3 To Supply Power Source
3.1 Power Supply to Main Circuit
3.2 Operation Check
4 Operation Checks and Component ReplacementProcedures
5 Type Illustration of ICs, Transistors and Diodes
6 Schematic Diagram
6.1 Schematic Diagram Notes
6.2 Schematic Diagram
7 Printed Circuit Board Diagram
8 Block Diagram
9 Wiring Connection Diagram
10 Measurements and Adjustments
10.1 Measurement instruments and Special tools
10.2 Output Voltage Adjustment
11 Terminal Function of ICs
11.1 IC701 (M38503M2404F) : Micro Computer

12 Replacement Parts List
13 Cabinet Parts Location
14 Packaging
PV
PV

Service Manual
TOP NEXT
AD9907176C2
Control Amplifier
●SU-C909U
Colour
(K)..........Black Type
Area
(E)..........Europe and Russia.

© 1999 Matsushita Electric Industrial Co., Ltd. All rights reserved. Unauthorized copying and distribution is a violation of law.
•@
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1 Note
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Refer to the servise manual for Model No. SE-A909S (ORDER No. AD9907177C2) for information
on Accessories, Connections, Operations and Packaging.
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2 Location of Controls
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3 To Supply Power Source
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This unit SU-C909U is designed to operate on power supplied from the Power Amplifier SE-A909S.
When operating the unit SU-C909U alone for testing and servicing, without having power supplied
from the Power Amplifier SE-A909S, use the following method.
3.1 Power Supply to Main Circuit
3.2 Operation Check
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3.1 Power Supply to Main Circuit
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1. Apply 10 V AC power to the section between the point TP1 and the point TP2 . Shown in
Fig.1
2. Connect the DC+12 V to+15 V (more than 0.1 A) to the point TP5 , and the GND terminal to
the point TP4 using the DC power supply. Shown in Fig.1
3. Connect the DC -12 V to -15 V (more than 0.1 A) to the point TP3 , and the GND terminal to
the point TP4 using the DC power supply. Shown in Fig.1
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3.2 Operation Check
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1. Input a signal (1 kHz, 100 mV) to the each line-in terminal.
2. Connect the oscilloscope or the speaker with the built-in amplifier to the PRE OUT terminals and
check if the signals are outputting from this unit.
Fig.1
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4 Operation Checks and Component
Replacement/Procedures
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5 Type Illustration of ICs, Transistors and
Diodes
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6 Schematic Diagram
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6.1 Schematic Diagram Notes
6.2 Schematic Diagram
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6.1 Schematic Diagram Notes
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●This schematic diagram may be modified at any time with the development of new
technology.
Notes:
❍S801:
VGCA switch (
)
❍S802:
Tape monitor switch (TAPE MONITOR)
❍S804:
Input select switch (SELECTOR)
❍S805:
Unit on/off switch (
/I)
❍VR301:
Volume control VR (VOLUME)

❍VR311:
Output voltage adjustment VR (L ch)
❍VR312:
Output voltage adjustment VR (R ch)
❍VR401:
Balance control VR (BALANCE)
❍VR402:
Tone control VR (BASS)
❍VR403:
Tone control VR (TREBLE)
●Indicated voltage values are the standard values for the unit measured by the DC electronic
circuit tester (high-impedance) with the chassis taken as standard. Therefore, there may exist
some errors in the voltage values, depending on theinternal impedance of the DC circuit tester.
No mark : Power ON
●Important safety notice:
Components identified by mark have special characteristics important for safety.
Furthermore, special parts which have purposes of fire-retardant (resistors), high-quality
sound (capacitors), low-noise (resistors), etc. are used.
When replacing any of components, be sure to use only manufacturers specified parts shown
in the parts list.
●Caution!
IC and LSI are sensitive to static electricity.
Secondary trouble can be prevented by taking care during repair.
Cover the parts boxes made of plastics with aluminum foil.

Ground the soldering iron.
Put a conductive mat on the work table.
Do not touch the legs of IC or LSI with the fingers directly.
●Voltage and signal line
●
: Positive voltage line
●
: Negative voltage line
●
: Phono signal line
●
: Tape rec signal line
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