Sansui QA 7000 Service Manual

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REGULAR MATRIX

SERVICE MANUAL

4-CHANNEL AMPLIFIER
SANSIII 00-7000

SANSUI ELECTRIC. CO., LTD.

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Sansui. QA.7000

This service manual is designed for service engineers to repair,
adjust, maintain and order the replacement parts of the QA-7000
corrctly.

When ordering the parts, use the stock number and parts name speci-
fically referring to the Parts Locations & Parts List.

For general usage and maintenance of the unit, please refer to the
Operating Instructions attached with the unit.

TABLE OF CONTNETS

Section Title

1. SPECIFICATIONS .....................................
2. BLOCK DIAGRAM AND LEVEL DIAGRAM.
2-1. Block Diagram ..
2-2. Level Diagram ..
3. ADJUSTMENTS ............................... i ,
3-1. Regulated Power Supply Board Adjustment .................. 4
3-2. Level Meter Adjustment ................................... 4
3-3. Driver Circuit Board Adjustment.
4. TROUBLESHOOTING CHART .........................
4~1, Troubleshooting on Power Supply Section .................. 6
4-2. Troubleshooting on Protector Section .....
4f3. Troubleshooting on 2-CH Section .................
4-4. Troubleshooting on PHONO-1, 2 Section .........

4~5. Level Meter Inoperative ..................... . 8
4-6. Troubleshooting on Q5 SYNTHESIZER Section ..... 8
4-7. Troubleshooting on Main Section .......................... 8
5. PARTS LOCATIONS AND PARTS LIST . 9
5-1. F-2028A Equalizer Circuit Board ........................ 9. 10
5-2. F-2031 Switch Control Circuit Board ........................ 10
53. F-2066 Tone Circuit Board ........... . , 11, 12
5-4. F-2064 Meter Circuit Board ................. . . i .13
5-5. F-2043 Tone Control Circuit Board ......... 14
56. F-2010 B.T.L. Circuit Board ............... 15
5-7, F-2022 Protector Circuit Board ............... .. . . . .15. 16

5-8. F-1354B Driver Circuit Board .............
5-9. F-2032 Fuse Circuit Board .........
5-10. F-2033 Power Supply Circuit Board .......
5-11, F-2038 Fuse Circuit Board .............
5-12. Other Parts (Front Side) . . .
5-13. Other Parts (Top Side) .................
5-14. Other Parts (Bottom Side) .................

6. SCHEMATIC DIAGRAM OF AUDIO SECTION-1 .
7. SCHEMATIC DIAGRAM OF AUDIO SECTION-2 .
8. PACKING LIST ...........................
9. ACCESSORY PARTS LIST
10. MAINTENANCE ....................... .
10-1. Voltage Adjustment ................................... 22

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, QA-7ooo

4-3. Troubleshooting on 2-CH Section

Symptom Check Point
*Set B.T.L. switch to off
1. One channel inoperative

1) Quick Acting Fuses open
()1, F02 (F03, F04) on F-2038

1-1) After replacement, quick acting

.fl

1-2) After replacement, quick acting

2) Quick Acting Fuses_not open
F01, F02 (F03, F04) 'on F-2038

2-1) Reverse L and R-ch at PRE OUT,
MAIN {N

1) No sound at MIR-J.

2) R and L-ch sound reverses

2-1) Level meter operative--~-~4.

2-2) Level meter inoperative-*5.

-6

1) Protector circuit board F-2022 operative~-~-~1Z.

4-4. Troubleshooting on PHONO-1, 2 Section
1. One channel inoperative

fuse opens againml

fuse not open M2.

Cause & What to Do

Defective main amp. (See 4-7.)

Confirm the center voltage which is with-
in 2.5V

Defective main amp. (See 4~7.)

Defective TR09, TRI3, TRl7 (TR10, TR14,
TRIB) on F-2066

Imperfect contact of S701-af (S701-bf)
on SELECTOR switch

. imperfect contact of 501-: (SOl-d) on 2-
,VCHJAPEMONJTQR switch V ,,

A imperfect contact of SOS-c (SO3-d) on 4-

CH TAPE MONITOR switch

. Imperfect contact of S702-af (5702-100 on

FUNCTION switch

. Defective TR01, TROS (TROZ,'TR06) on

2. Both channels inoperativektm
11,

F-2066

Defective power section (See 41.)

Grounding of PRE OUT and speaker
terminals not released (See4-2.)

Even if center voltage on one channel is
more than 2.5V on F-13543, both (or 4
channel) function would be inoperative
by protector circuit

. imperfect contact of S701-ar (S701-br)

on SELECTOR switch

. Defective TR601, TR603, TR605 (TR602,

TR604, TR606) on F-ZOZBA

. imperfect contact of S701-af (S701-bf)

on SELECTOR switch

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8. PACKING LIST 10. MAINTENANCE

10-1. Voltage Adjustment

Pa!!! No. Stock No. Descrlptlon

The Voltage Selector on the rear panel enables you to
1 901720! Inner Packing (upper) operate at correct voltage in any areas. The voltage has
2 9027692 Slylolorm Packing been preadjusted at the factory, but can be easily
3 9027692 Stylolorm Packing changed as follows.
4 9027691 Stylolorm Packing 1) Remove the two screws securing the name plate on
5 9027692 Siyloiorni Packing the units rear panel, then remove the name plate.
6 9007391 Canon Case 2) Unplug the Voltage Selector plug once, and reset it

so that the arrow mark on it faces the correct voltage
indication. Also change the power fuse when the
power supply voltage has changed. For 100, 117 volt
operation, use a 4-ampere glass-tubed fuse. For 220/
240 volt operation, use a Zvampere one.

Note: The Voltage Selector can be used to eliminate
the trouble caused by the considerable voltage
fluctuation. In this case, it should be set to the
peak voltage.

100V 240V
240V II7V 140V II7V
O
120V 100V 2 IOOV
11 7V 220V

240V II7V 240V II7V
O O
220V 100V 220V IOOV

9. ACCESSORY PARTS
LIST

Stock No Description
9406020 Polishing Cloth
0433620 3A Quick Acting Fuse
9207070 Operating Instructions
92207070 Operating Instruction sheet

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