Sansui 500A Service Manual

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SERVICE MANUAL

AM/ FM MULTIPLEX STEREO TUNER AMPLIFIER

SANSUI ELECTRIC COMPANY LIMITED

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CONTENTS

TROUBLESHOOTING AUDIO SYSTEM ........ 3, 4,
AMPLIFIER TROUBLESHOOTING CHART... 5,6,7, 8,9, 10,11.12,13
REMOVING THE FRONT PANEL

BONNET & BOTTOM PLATE ................ 14
DIAL MECHANISM ...................................... 14
SCHEMATIC DIAGRAM ................................ 15,16
BLOCK DIAGRAM ........................................ 17
PARTS LAYOUT .......................................... 17
PRINTED CIRCUIT SHEETS ........................ 19
SELECTOR CHART ...................................... 20
CHASSIS DIAGRAM ...................................... 21
ALIGNMENT ................................................ 22, 23, 24
PARTS LIST .................................................. 25, 26, 27, 28, 29

COLOR CODE ................................................ 3O

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Symptom

Probable Cause

Check Point

(Continued)

7. Divergence in adjustment

Optimum adjustment often needs to

of: ' use measuring instruments.
a. Tracking. TC4, TCS
b. I.F.T. T301. T302
Distortion . Defective overall See Distortion over all program
section sources.
. Defective AM section . Divergence of voltage Measure voltage in AM section and
specified in CIRCUIT replace defective element.
DIAGRAM"
. Detector diode, aging or D301
weak
. Insufficient capacity of C305, C306
capacitor
. Divergence in adjustment See Weak sound.
I-Ium . Defective overall See Hum over all program sources
section
. Defective AM section . Inner contact or poor V4, V6
insulation of tube.
. Insufficient capacity of C305, Co
I capacitor.
Noisy i . Amplifier is OK. See- TROUBLESHOOUING AUDIO

SYSTEM WHEN THE AMPLIFIER
IS GOOD".

. Defective

overall
section

SeeNois over all ro ram sources.
y P 8

. Defective AM section

. Aging or defective tube.
2. Loose contact of rotary

switch.

V4
52a, 52b

Tuning meter
does not work
normally.

. Defective AM tuner

Check as described above.

. Defective tuning indicator circuit

See FM RECEPTION: Tuning meter
does not work normally.

USE OF RECORD PLAYER (MAGNETIC), TAPE DECK

' Symptom

Probable Cause

Check Point

No sound

. Program source de-

Check and repair or replace.

resistor.

fective
. Defective overall See No sound over all program
section sources".
. Divergenceof voltage . Divergence of voltage Measure voltage in head amplifier
specified in CIRCUIT section and replace defective element.
DIAGRAM
. Defective capacitor 01' 0507, C517, R510, R324, C505, C315