Troubleshooting Guide - NAD CI 940 Service Manual

Connect AC Cord from CI940
POWER ON BY POWER SWITCH OF REAR PANEL
NO
IS THE AMBER LED LIGHTED?
YES
CAN PRESSING STB KEY MAKE NO
THE UNIT WORK NORMALLY?
YES
NO
IS THE SPK OUT NORMAL?
YES
NO
IS 12V TRIGGER NORMAL?
YES
NO
IS AUDIO SENSE CIRCUIT NORMAL?
YES
NO
IS BRIDGE MODE NORMAL?
YES
OK

TROUBLESHOOTING GUIDE

YES
IS IT RED?
NO
NO
IS POWER MODE RIGHT?
YES
RED
IS THE ABMER LED AMBER
OR RED?
AMBER
CHECK MCU CONTROL CIRCUIT
NO
IS THE OUTPUT DC LEVEL NORMAL?
YES
NO
IS THERE SIGNAL OUTPUT?
YES
YES
IS THE THD HIGH OR ABNORMAL
WAVEFORM?
10
NO
IS THE STANDBY SINGAL LOW
YES
NO
IS INPUT BOARD OUT NORMAL?
NORMAL?
YES
YES
IS THE MUTE SIGNAL OFF?
NO
NO
IS PROTECT CIRCUIT NORMAL
YES
CHECK POWERAMP CIRCUIT
CHECK THE LED CONTROL CIRCUIT
,AND PROTECET CIRCUIT
CHECK THE 5V SUPPLY CIRCUIT
CHECK THE 5V SUPPLY CIRCUIT
OR CHANGE AUTO ON MODE TO
TO TRY AGAIN
CHECK THE PROTECT CIRUIT
CHECK THE STANDBY CONTROL
CHECK POWERAMP CIRCUIT
CHECK INPUT BOARD CIRCUIT
CHECK THE MUTE CONTROL
CIRCUIT
CHECH NJW1194 AND PREAMP
AMP CIRCUIT
OPEN THE UNIT FOR OVERALL
CHECK
CHECK 12V OUT CONTROL CIRCUIT
CHECK AUDIO SENSE CIRCUIT
CHECK PHONE CIRCUIT
OR CONNECTION