Pioneer sx 680 service manual

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MODEL SXA680 COMES IN FOUR VERSIONS DISTINGUISHED AS FOLLOWS:

Type Voltage Remarks

KU 120V only U.S.A. model

KC 120V only Canada model

S 110V, 120V, 220V and 240V (Switchable) General export model

S/G 110V, 120V, 220V and 240V (Switchable) US. Military model I

MODEL SX-690 COMES IN THREE VERSIONS DISTINGUISHED AS FOLLOWS:

Type Voltage Remarks
KU 120V only U.S.A. model

HG 220V and 240V (Switchable) United Kingdom model

HGW4 220V and 240V (Switchable) Europe or Oceania model

Although the basic features of models SX-680 and SX-GQO are the same, there are a few minor changes in design.
The variations in safety standards in different countries has also necessitated variations in power supply and circuit
component specifications. Furthermore, the difference in Dre-emphasis characteristics employed by FM broad-
casting stations has also meant variations in de-emphasis circuit time constant.

This service manual is applicable to the SX-680/KU. For servicing of the other types please refer to the ad-
ditional service manuals.

CONTENTS

1. SPECIFICATIONS ..................... 3 9. SCHEMATIC DIAGRAMS, P. C, BOARD
2. FRONT PANEL FAClLITIES .............. 5 PATTERNS ANDPARTS ST
3. BLOCK DIAGRAM ..................... 7 9" Ml5°93"ea ---------------------- 17
4. ClRCUIT DESCRIPTIONS 9.2 Schematic Diagram ................. 19
4-1 Tuner Section ................... 8 9.3 P. C. Board Connection Diagram ........ 21
4.2 Audio Section .................. 8 9.4 FM Frontend (GWB-lOI) ............. 23
5. DISASSEMBLY ....................... 10 9'5 Tape 59 GWXIBS """""" 24
6. PARTS LOCATION ___________________ 11 9.6 De-emphasis Switch Assembly (GWX-iSO). . 24
7. DIAL CORD STRINGING ................ 13 9'7 PM" Jac" Assemb'y (wa'ngl ----- 24
8. ADJUSTMENTS 9.8 Fuse Holder Assembly (GWX-178) ....... 24 -
8.1 FM Tuner IIIIIIIIIIIIIIIIIIIII 14 9.9 Indicator Assembly (GWX-177) ......... 24
8.2 AM Tuner IIIIIIIIIIIIIIIIIIIIIII 16 9.10 Main Board Assembly (GWM117) ....... 25
10. PACKING ........................... 29
11. EXPLODED VIEW ..................... 30