Onkyo TX-7920 - User Manual

Ref. No. 3420
ONKYO
SERVICE
MANUAL
QUARTZ SYNTHESIZED
TUNER AMPLIFIER
MODEL TX-7900
MODEL TX-7920
Black and Silver models
SAFETY-RELATED COMPONENT WARNING! !
COMPONENTS IDENTIFIED BY MARK A ON
THE SCHEMATIC DIAGRAM AND IN THE PARTS
LIST ARE CRITICAL FOR RISK OF FIRE AND
ELECTRIC SHOCK. REPLACE THESE COMPO-
NENTS WITH ONKYO PARTS WHOSE PART
NUMBERS APPEAR AS SHOWN IN THIS
MANUAL.
MAKE LEAKAGE-CURRENT OR RESISTANCE
MEASUREMENTS TO DETERMINE THAT EXPOSED
PARTS ARE ACCEPTABLY INSULATED FROM
THE SUPPLY CIRCUIT BEFORE RETURNING
THE APPLIANCE TO THE CUSTOMER.
ONKYO
AUDIO COMPONENTS
TABLE OF CONTENTS
Specifications eee errr ee eee eee eee ee eee Tee eee eee eee ere Terre ree eee ere 2
Service procedures::+++i+sssssssstssesesesseeesseeseseeseserseeageeens 3
Exploded view Model TX-7920++:+++:+++s+sssesseseseeeeseeessseeneens 4
Parts Ist Model TX-7920 tse: wvesncwses ceracmmamninsaeennenee 5
Exploded view Model TX-7900++++++++++:ssess+sessesesseeereeesaeeens 6
Parts list Model ‘TX-7900 issssster<eomnns sane venwavanes senna canon cones 7
Block diagram Model TX-7920-++++1:+++ssessseerseeesseersese seeeees 8
Block diagram Model TX-7900-+++++:++1s+sessseerseseseeteseeeeeeeens 9
IC block diagram and descriptions::::::1++++sseeeseseeseeseerees 10
Packing view svrcessscessceeeseeessseeseessenseneeseesesescnesensereanneens 17
Adjustment procedures ree eee eee eee er errr) 18
Printed circuit board view from bottom side-+r+++++rrr + est+* 21
Schematic diagram
Model "P7920: sere: ose cwaes uedewvensaes eonnenamenaee eemaseeeninenl 23
Model TX: 7900» «sss sentecnnsaxonenen nonce dvtineanennasaerawargicaeenines 25
Printed circuit board-parts list
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Model 1X. 20 0Gxrtceswens corweswaieaee dennwonatennigipien vpeiciirnay 9 tate wea 39
TX-7900/TX-7920

Summary

Safety Component Warnings

Critical Component Identification

Components marked A are critical for fire and electric shock risk. Use specified parts.

Specifications Overview

Amplifier Section Specifications

Tuner Section Specifications

Service Procedures

Fuse Replacement and Safety Checks

Guidelines for replacing fuses and performing essential safety tests after repairs.

Parts List - TX-7900

Critical Part Identification Warning

Warning on critical parts marked A; replacement requires specific Onkyo part numbers.

Block Diagram - TX-7920

Block Diagram - TX-7900

IC Block Diagram: LM7001

LM7001 Terminal Description

IC Block Diagram: μPD17103 CX-528

μPD17103 CX-528 Terminal Description

IC Block Diagram: μPD75268 CW-025

μPD75268 CW-025 Terminal Description

Adjustment Procedures - General

Preparation and Standard Knob Settings

Amplifier Idling Current Adjustment

Procedure for adjusting amplifier idling current using a DC voltmeter.

Adjustment Procedures - FM Section

FM IF and VCO Adjustments

Adjusting FM IF stage and VCO using test equipment.

FM Stereo Distortion and Separation

Adjusting FM stereo distortion and separation.

FM Tuned Indicator Level Adjustment

Adjustment Procedures - AM Section

AM OSC and RF Coil Adjustments

Muting and Indicator Level Adjustments

Schematic Diagram - TX-7920

Schematic Diagram - TX-7900

Onkyo TX-7920 Specifications

General

Brand	Onkyo
Model	TX-7920
Category	Amplifier
Language	English