NAD 512 - Troubleshooting Guide

TROUBLESHOOTING GUIDE
SET POWER SWITCH TO ON
NO
1S POWER TURNED ON ?
YES
NO
CAN TRAY BE OPENED ?
CAN TRAY BE CLOSED ?
YES
DOES INITIAL READING OCCUR ?
YES
NO
CAN DISC BE PLAYED ?
YES
AUDIO OUTPUT IS CORRECT ?
YES
CHECK FUSE F501, F502 OPEN ?
YES
F501 OR F502 DEFECTIVE
IS THERE OPEN/ CLOSE KEY SIGNAL
INPUT ? Q104 PIN 13
YES.
CHECK OPEN/ CLOSE SIGNAL AT IC104,
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YES
IS LOADING MOTOR DRIVE CIRCUIT
OPERATION NORMAL ? Q507 PIN 9
YES
LOADING MOTOR AND LEAD WIRE DEFECTIVE
OR LOADING PART OF MECHANISM DEFECTIVE.
NO
CHECK LASER LIGHT ?
NO CHECK POWER SUPPLY NO
CIRCUIT NORMAL ?
YES
NO
iS OSCILLATOR CIRCUIT
OSCILLATING ?
$701 SWITCH, D704 DIODE DEFECTIVE
OR PATTERN AND CONNECTOR OPEN
MICROPROCESSOR IC Q104 DEFECTIVE.
MOTOR DRIVE IC Q507 DEFECTIVE.
YES YES
CHECK LASER CIRCUIT CORRECT ? RF SIGNAL OUTPUT ?
YES YES
CONNECTING OR PICKUP DEFECTIVE. FEED MOTOR OR WIRING DEFECTIVE
NO
Q101 OR Q110 DEFECTIVE
NO
CHECK TRACKING SERVO CIRCUIT CORRECT ?
YES
CHECK DISC OR MECHANISM AND CONNECTOR
NO
tS POWER SUPPLY NORMALLY ?
YES
CHECK OUTPUT PULSE AT PIN 76,78,80 OF 0103
IC Q103 DEFECTIVE.
IC Q201 OR Q202 DEFECTIVE.
CHECK OUTPUT SIGNAL AT PIN 1.7 OF 0201, Q2G2
YES
NO
CHECK OUTPUT SIGNAL AT PIN 1.7 OF Q203, Q204
YES
CHECK MUTE CIRCUIT Q207, Q208, 0209, 0210
YES
LINE OUT PLUG OR PATTERNS DEFECTIVE,
DOES LENS MOVE UP AND DOWN ?
NO
CHECK POWER SUPPLY PATTERNS.
IC Q203 OR 0204 DEFECTIVE.
MUTE CIRCUIT DEFECTIVE.
POWER SUPPLY PATTERNS OPEN
OR Q503, Q504, Q505 DEFECTIVE
CRYSTAL 2201 DEFECTIVE,
Q101 DEFECTIVE
NO
CHECK FOCUS SIGNAL OUTPUT ?
YES
CHECK CONNECTING OR PICKUP
SERVO IC Q102 OR DRIVE TRANS, Q604-Q607 DEFECTIVE.
YES
CHECK OUTPUT PULSE AT PIN 11,14,18,21 OF Q105 IC Q103 DEFECTIVE,
YES