Sansui QRX 7500 Service Manual

Page 2

QRX-7500

This service manual is designed for service engineers to repair,
adjust, maintain and order the replacement parts of the QRX-7500
correctly.

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

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

TABLE OF CONTENTS

Section M Pa_ge
1. SPECIFICATIONS ................................................ 2
2. BLOCK DIAGRAM AND VALUE OF EACH LEVEL. ...3,4
3. ALIGNMENTS AND ADJUSTMENTS ......................... 5
3-1. Regulated Power Supply Board Adjustment ............... 5
3-2. Level Meter Adjustment ............................. 5
3-3 Driver Circuit Board Adjustment ...................... 6
3-4, FM IF Alignment .................... .r ......... 7
3-5. FM Dial Calibration and RF Alignment ................... 7, 8
3-6

FM Signal Meter, Mono Distortion, Tune Meter and

Muting Adjustment. - ».
3-7, MPX Alignment ............................................ 9 1'
3-& AM IF, Dial Calibration, RF and Signal Meter Alignment 9, 10 '

4-. THREADING 0F DIAL CORD' .. . .M. 11
5. TROUBLESHOOTING CHART ............................ 11
5-1 Troubleshooting on Power Suoply Section ............... 11

5-2. Troubleshooting on Audio Section ......

5-3. Troubleshooting on RF Section .......
G. PARTS LOCATIONS AND PARTS LIST

6-1. F4484 Tone Control Circuit Board

62. F-149O De

6-3. F-1479A Tuner Circuit Board ................. .H

6-4. F4515 Protector 8: Power Circuit Board .................. 19, 20

6-5. F-2048 Vario-Matrix Circuit Board .................. 21, 22
6~6. F-2047 Vario~Matrix Circuit Board . ........... 23, 24
6-7. F4485 Meter Circuit Board ....................... 24
6-8 F-1Sl4 Driver Circuit Board ............................ 25, 26
69. F-IS16 Accessory'Circuit Board ........................... 26
640. F-1487 Volume Circuit Board ....................... 26 1
6-11. F1488 Connector Joint Circuit Board .. ............. 27
6-12. F-1486 Filter Circuit Board ........................... 27
' 6-13 F-2085 Equalizer & CD-4 Main Circuit Board .. . ......... 28
6-14. F-2090 CD-4 Sub Channel Unit Circuit Board. . ....... 29,7 30
6-15, Other Parts (Front Side) ,. ,7 .................... 31, 32
6-16. Other Parts (Top Side) ................... 33
(r17. Other Parts (Bottom Side) ................................ 34
7. PACKING LIST ........... 35
8. ACCESSORY PARTS LIST 35

9.. SCHEMATIC DIAGRAM 0F TUNER SECTION .................. 36
10. SCHEMAITC DIAGRAM 0F AUDIO SECTION H: ............. 37, 38