Onkyo A 8780 Service Manual

Page 1

ONKYOQ SERVICE MANUAL

Integrated Stereo Amplifier
MODEL A-8780

a

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 SHOCKI
REPLACE THESE COMPONENTS WITH ONKYO PARTS
WHOSE PARTS NUMBERS APPEAR AS SHOWN IN THIS
MANUAL.

MAKE LEAKAGE-CURRENT OR RESISTANCE MEA-
SUREMENTS TO DETERMINE THAT EXPOSED PARTS
ARE ACCEPTABLY INSULATED FROM THE SUPPLY
CIRCUIT BEFORE RETURNING THE APPLIANCE TO
THE CUSTOMER.

TABLE OF CONTENTS

A

REF. NO. 3376

Item

Specifications
Precautions

Block diagram

Chassis exploded view
Adjustment procedures
Circuit description

IC block diagram

Printed circuit board parts list
Packing pan list

System connections
From panel facilities
Printed circuit board View
Schematic diagram

ONKYO

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Page 3

BLOCK DIAGRAM

DBII. DQI2

POWER
INPUT SELECTOR 33(5)? 6 INDICATOR
EOUALIZER AMP. 52.3 52.2 52 MICRO PROCESSOR
PHONO© 4": .L TAPE' TU ' R CD 30 POWER/BACK 2 RELAY
" 0 K52 DRIVE
5214 SELECTOR
5' TAPE 2 3233-4' A I INDICATOR
KS I j; I ( )
- soil? 3236.3! : LED
I
CARTRIDGE SELECTOR KS O
MIND/STBY 9 '3 oaI4.OaI5 .®Z
R ODE K 2 39 WTING }_
ROTA v ENC R ~
UNPUT K I Q80, DRIVE [1le DZIB
CO C CI
0 SELECTOR) K o MUTE .o MUTING _ I
I. 3~e DRIVE
TUNER G j') ENCD 34 0307 REMOTE
REM '" I O SENSOR
Aux-I <3 ____( ::):MOTOR SEL UP
[/- DRIVE '2 SEL DOWN UOIB
/ I6
_ oaoz 2' 5Y5 IN Bus LINE
AUX 2G lxao. osc ' svs OUT I5 VI] BUS LINE
SOURCE =4M -V (RI)
REC SELECTOR a DIRECT TONE - oeoe __,_fl
$28! T,.DAT.T2 ' JCDNTROL IA osc2 I
Is , -©PI-IONEs
[REC © | j J F OFF RESET +aI21
DAT Is I
I VICTOR VOL UP
23 0804 I -��I-)
PL" G ° 537|I DRIVE 4 VOL now as lmaI I I \
RL853 A
I I 0803 -MJ /
REC ©J 0 I POWER AMP age-Tm-
. I SPEAKERS
TAPEI 7'7 525] -L R185! 0
PLAY i VOLUME L ,,, \
I B
RELAY RL25I I RL852 /
,_____ SURBO AMP 4r
REC ©-®)_L cg 53m 7 PROTEC SPE§5§R§_ _S_8\5I (*3
TAPE-2|: @ 7» (W 3 TONE MUTING [BALANCE 40R - Egg RE LAY
PLAY 1, DIRECT 05 I9 085| I
1.-. MODE
T_2 :I MONITOR REL M I
RELAY I
RL951 F902 DRIVE RELAY _'_I
3/ ' ' 025| aalz DRIVE
-+aa (2I 4v) 52 '3 0552. 0853
T902
AC -»-Be (-22.Iv) 3 CONST
INPUT : -H- ~ - +Bl3 (5.7V)
+39II2.9V) - mTACE
+Bl ~ +B3I54.7V) 0805

-r

AC OUTLETS

AC LINE

._3_

092 I
-u- '
OISE-I. 10905

-BI~ -83(-537V)

0902090440906

VOLTAGE + as (22.4v)
CONST. _
VOLTAGE BM, 22.3w

AC LINE

-._

-_-.+BIZII2.7VI

A-8780