Onkyo M 508 Service Manual

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SERIAL N0. 3232

ONKYO SERVICE MANUAL

Stereo Power Amplifier
MODEL M-508

STD 7,7,, IEEVACfiOI-Iz 7
T U6 7 ivzrzov ACTfiz
T UQ _, 240V AC 50Hz h

uw Iii-6V; 220v AC, 50/60117.

SAFETY-RELATED COMPONENT WARNINGI!

COMPONENTS IDENTIFIED BY MARK [L ON THE
SCHEMATIC DIAGRAM AND IN THE PARTS LIST
ARE CRITICAL FOR RISK OF FIRE AND ELECTRIC
SHOCK. 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

Specifications ............................ 2
Precautions .............................. 2
Block diagram ............................. 3
Adjustment procedures ....................... 4
Front panel facilities ........................ 4
Packing procedures ......................... 5
Chassis-exploded View ....................... 6
Printed board parts list ....................... 8
System connections ......................... I 1
IC Block diagram ........................... [2
Schematic diagram (UD) . . ; .................. 13

(U6) ..................... l7

(UW) ..................... 21
Printed circuit board View. . . .................. 15

ON KYO®
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A.

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SPECIFICATIONS

Music Power Output;
Continuous Power Output;

Total harmonic distortion:

2 x 450 watts at 4 ohms, lkI-lz (DIN) 2 x 260 watts at 8 ohms, lkHz (DIN)

2 x 315 watts at 4 ohms, IkHz (DIN) 2 x 215 watts at 8 ohms, lkI-Iz (DIN)

200 watts per channel, min. RMS, at 8 ohms, both channels driven, from 20 Hz to 20 kHz,
with no more than 0.003% THD

01003% at rated power

0.003% at 1 watt output

Intermodulation distortion: 0.003% at rated power
Frequency response: +0, ~1.5 dB at le to lOOkHz
Input sensitivity: 1.0V
Input impedance: 20kohms
Damping factor: 140 (8 oluns, IkHz)
S/N ratio: 120 dB (IHFA, shorted)
Outputs: SPEAKERS l & 2, AC OUTLET (l20V models only)
Inputs: INPUT (V ARIABLEI DIRECT)
Power Supply: European models: AC 220V, 50Hz
Canadian models: AC 120V, 60Hz
British and Australian models: AC 240V, 50Hz
Worldwide models: AC 120V, 60Hz
(Switchable): AC 220V, SOHZ
Dimensions: 465(W) x I85{H) x 426(D) mm
18 5/16" x 7 9/32" x 16 25/32"
Weight: 25 kg, (55.1 lbs.)
Specifications and features are subject to change without notice.
PRECAUTIONS
l. Replacing the fuses
For continued protection against risk fire, replace only with same type and same rating fuse,
CIRCUIT NO. PART NO. DESCRIPTION
F80], F802 252032 7A (ST-6), Primary fuse (120V, I20V/220V model)
F803, F804 252077 4A-SE-EAK, Primary fuse (220V, HOV/220V, 240V model)
F702 252044 2A (ST76), Secondary fuse (120V, 120VI220V model)
F702 252074 2A-SE-EAK, Secondary fuse (220V, 240V model)
2. Replacing the lamp
This unit uses the lamp listed below.
CIRCUIT N0, PARTS NO. DESCREPTION
PL88I, H.882 210191 PL14V ISOmA (Green)
PL883, PL884
PL885, H.886 210192 PL14V 150mA (Orange)
PL887, H.888
3. Insulation resistance mesurement (Only USA, model)

Connect the insulating-resistance tester between the plug of power supply cable and the terminal GND on the back panel.
Specifications; More than 10 M52 at 500V.

. Voltage selector (rear panel)

Worldwide models are equipped with a voltage selector to conform with local power supplies. Be sure to set this switch
to match the voltage of the power supply in your area before turning the power switch on. Voltage is changed by sliding
the groove in the switch with a screwdriver or similar instrument to the up or down position. Confirm that the switch
has been moved all the way to the up or down before turning the power switch on. If there is no voltage selector switch
on the unit you have purchased, it can only be used in areas where the power supply voltage is the same as that of the

unit.
[:11] CE
220v 120v 220v 120v
at Ac 120v at Ac 220v

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PACMNG

GD-

PROCEDURES

REF NO.
A351
A852

A853
A854
A855
A856
A85 7
A 858

A880

PARTS N0.
29051307
29091081
29091037
29091084
29095319
29100038A
29095447
260012
282301

DESCRIPTION

Master carton box

Pad ass'y, left

Fad assy, left [X]

Pad assy, right

500 x 1000mm, Protection sheet.
720 x 950mm, Poly-Vinyl bag
Sheet (P)

Damplon tape

Sealing hook

Accessa ry bag assy

293 4 1001
293 4 1002
2934 1009
29365006 *7
2936501 2A
2936 800 2C
2935 8002C
2010097

29 100006A
25055018

2 5055251

2 8330072

Only 120V models

,: Only 220V models

: Only 120V/220V models

: Only USAI models

: Only Military market models

Only British and Australian models

Instruction manual [D] [N:
Instruction manual [G] [WHQ]
Instruction manual [X]
Warranty card -N l
Warranty card [X]
Service station list [N]
Service station list [x]

Connection cable
250 x 350mm, Poly-vinyl bag for accessary

CVK-l, Conversion plug [WI
CVCP, Conversion plug [WJ
Cap (AC Outlet) 2X.

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