Pioneer sx 838 service manual

Page 1

SERVICE MANUAL

AM/FM STEREO RECEIVER

X-B3B

KCU, F, GN

NOTE:

MODEL SX-838 COMES IN THREE VERSIONS DISTINGUISHED AS FOLLOWS:

I
Round label on
rear panel Voltage Type

KCU 120V only UL (USA) and USA (Canada)
approved

F 5-pusiti0n selector Genera] export model

GN 220V only SEMCO (Sweden), NEMCO (Norway)
and DEMCO (Denmark) approved

GDPIONEER ,

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sx-Baa
CONTENTS

About 220V only model labeled GN"

This model whose rear panel is labeled "GN" circular mark operates only on 220V,
substantially in its circuit design from two other models. When repairing this model,
please see the manual on page 75 and the followings which include such items as Circuit
connection diagram, Miscellaneous parts list, Schematic diagram of power supply circuit
assembly, P.C. board pattern and its parts list.

Before servicing, also please do not fail to check to see if the "GN" mark is labeled on the
rear panel.

1. SPECIFICATIONS ........................................ 3
2. FRONT PANEL FACILITIES ................................ 5
3. CONNECTION DIAGRAM .................................. 7
4. BLOCK DIAGRAM ....................................... 9
5. CIRCUIT DESCRIPTION ................................... 11
6, PACKING METHOD AND PART NUMBERS ...................... 12
7. LEVEL DIAGRAM ....................................... 13
8. DISASSEMBLV .......................................... 14
9, PARTS AND P.C. BOARD LOCATIONS ......................... 15
10. DIAL CORD STRINGING ................................... 17
11. ALIGNMENT PROCEDURE
11.1 English ......................................... 18
11.2 German ......................................... 22
12. EXPLODED VIEW AND PARTS LIST ........................... 26
13. SCHEMATIC DIAGRAMS, P.C. BOARD PATTERNS AND PARTS LIST
13.1 Circuit Connection Diagram and Miscellaneous Parts ............ 33
13.2 Tuner Assembly (AWE-041) ............................ 37
13.3 Equalizer Amplifier Assembly (AWF-011l ................... 43
13.4 Microphone Amplifier Assembly lAWM-064) ................. 46
13.5 Control Amplifier Assembly (AWG-029l .................... 48
13.6 Power Amplifier Assembly lAWH~O31) ..................... 53
13.7 Protection Circuit Assembly (AWM-025l ................... 58
138 Power Supply Circuit Assembly (AWR-OSS) ................. 61
13.9 Switch 8: Volume Assembly lAWX-070) .................... 64
13.10 Switch Circuit Assembly (AWS-073l ...................... 67
13.11 Switch Circuit Assembly (AWS-065l ...................... 70
13.12 Switch Circuit Assembly (AWS-OBGI ...................... 72
13.13 Switch Circuit Assembly (AWS-O74) ...................... 73
13.14 Switch Circuit Assembly (AWS-075) ...................... 74
13.15 5? Connector Assembly lAWX-DGZ) ...................... 74