Marantz 4270 Service Manual

Page 2

TABLE OF CONTENTS

SECTION PAG E
Introduction ........................................................... 1
Service Notes ........................................................... 1
AM Tuner ......... _ .................................................... 1
FM Tuner ............................................................. 2
Phone and Pre-Amplifier ................................................... 5
Dolby Unit ............................................................. 6
400R: Tone ............................................................. 5
Dolby Switch ........................................................... 7
Record Level (L) (R) ..................................... . ............... 7
Dolby FM Preset Level Controls ............................................. 7
400Hz Tone Switch ....................................................... 7
FM De-Emphasis Switch ................................................... 7
Power Amplifier ......................................................... 8
BTL (Balanced Transformer-Less) Connection .................................. 8
Power Supply Unit ....................................................... 8
Audio Trouble Analysis ................................................... 8
Test Equipment Required for Servicing ....................................... 9
AM Alignment Procedure ................................................. 9
FM Alignment Procedure ................................................. 10
Audio Adjustment ....................................................... 11
Automatic Voltage Regulator Adjustment ..................................... 11
Dolby Alignment Procedure ............................................... 11
Alignment Procedures of Dolby FM Preset Level Controls ......................... 12
Explanation of the Dolby Processing Chart ................................... 12
Parts List ........................................................... 28~43
Technical Specifications ................................................. 44, 45

LIST OF ILLUSTRATIONS

FIGURE PAGE
1 Block Diagram of the HA1156 ......................................... 4
2. Front Panel Adjustments Component Locations ........................... 14
3. Main Chassis Component Locations (Top View) ........................... 14
4. Rear Panel Adjustments and Component Locations ......................... 15
5. Main Chassis Component Locations (Bottom View) ......................... 15
6. Dial Stringing ....................................................... 16
7. FM Front End Assembly P100 Component Locations ....................... 17
8. AM Tuner Assembly P150 Component Locations ........................... 17
9. FM IF Amplifier Assembly P200 Component Locations ....................... 18

10. FM MPX Stereo Decoding Amplifier P300 Component Locations ............... 18

11. Phono Amplifier Assembly P400 Component Locations ....................... 19

12. Vari-Matrix Unit Assembly P500 Component Locations ....................... 19

13. Dolby Unit Assembly P600 Component Locations ........................... 19

14. Main Power Amplifier Assembly P700 Component Locations ................... 20

15. Power Supply Assembly P800 Component Locations ......................... 20

16. FM Cal, FM DeEmphasis Assembly P001 Component Locations ............... 21

17. Tone Amplifier Assembly PD01 Component Locations ....................... 21

18. Buffer & Pro-Amplifier Assembly PE01 Component Locations ................. 21

19. Balance Control Unit Assembly PGO1 Component Locations ................. 22