Onkyo TX 870 M Service Manual

Page 1

SERIAL NO. 3311

ONKYO SERVICE MANUAL

QUARTZ SYNTHESIZED
TUNER AMPLIFIER
MODELS TX-870/TX-870M

BHUD,BHUDN.MBHUDN IZOV AC,60HZ

MBHUWX lZOJZZOV AC, SO/GOHZ

SAFETY-RELATED COMPONENT WARNING TABLE OF CONTENTS

COMPONENTS IDENTIFIED BY MARK A ON
THE SCHEMATIC DIAGRAM AND IN THE PARTS Specifications ....................... 2
LIST ARE CRITICAL FOR RISK OF FIRE AND

s w d - .................... 3
ELECTRIC SHOCK. REPLACE THESE COMPO 5 7 I 4
NENTS WITH ONKYO PARTS WHOSE PART KP Ed 6W """""""""""""""
NUMBERS APPEAR AS SHOWN IN THIS Parts 1151 ---------------------- 5
MANUAL. Block diagramATuner section --------------- 6
Block diagram-Amplifier section -------------- 7
MAKE LEAKAGE CURRENT 0R RESISTANCE IC block dIa ram and descri lions IIIIIIIIIII 8
MEASUREMENTS TO DETERMINE THAT EXPOSED . g p
PARTS ARE ACCEPTABLY INSULATED FROM AdJUS'mem Procedures ----------------- - 18
THE SUPPLY CIRCUIT BEFORE RETURNING PC board View/parts lisI ----------------- 2]
THE APPLIANCE TO THE CUSTOMER. FM/AM {uney .................... 21
Display/Operation swiIch ---------------- 23
Pre. and power amplifier ---------------- 25
Tone control ..................... 23
Power Supply ..................... 29
Volume/Volume indicator --------------- 30
Packing view ....................... 3]

ONKYO
AIIIIIII BflMPIIIIIIIIS

Page 18

ADJUSTMENT PROCEDURES

Preparation 0 Standard knob position
0 Input TAPE MONITOR ................. SOURCE
FM mono: lkHz, 75kHz devir, 60dB/uV VOLUME ..................... Maximum
FM stereo: lkHz, L+R 67.5kHz devi.: Pilot signal l9kHz BASS/TREBLE/BALANCE ......... Center
7.5kHLdevir MODE...4.,.H,.........4..r.STEREO
AM: 400HZ, 30% mod, SPEAKER ..................... A
0 Output SIMULATED STEREO ........... OFF
Connect the non-inductive type resistor of 8 ohms to the DYNAMIC,BASS EXPANDER .......... OFF
speaker terminal A of left and right channels unless other- SELECTIVE TONE CONTROL .......... OFF
wise notedi MUTING/LOUDNESS ............. OFF
CARTRIDGE SELECTOR ........... MM
REC SELECTOR ................. SOURCE
Amplifier section

1 t Idling current adjustment

Connect the DC voltmeter to the terminalinD and VCT on

the power amplifier pc board.

Adjust the semi-fixed resistors R53! and R532 so that the

indication of voltmeter is 15 i ZmV.

Notes: VOLUME ............ Maximum, Open load,
Adjust after switching on for lSminutes.

® DUI] ® EIEIEI

R532 HI) E ch H53: iID E ch
IDLING IDLING
R"! Len

NAAF-3462-2

2. Check of operation of protection circuit
1) Check of operation of protection relay,
(1) Confirm that the relay turns ON approximately 5 seconds after the power switch is turned ON.
(2) The relay should turn OFF approximately 05 seconds after the power switch is turned OFF,
2) Check of DC detection
(I) Turn the power on with no load,
(2) After the speaker relay turns ON, apply DCl ~lt5V to the CD input terminals. Confirm that the relay turns OFF
(3) Confirm that operation is the same as (2) above when an input of DC- 1 ~ - 1.5V is applied
Note) Under no circumstances connect a load or short the speaker terminals when performing the above test

-18-