![background image](http://html.mh-extra.com/html/nad/c-725bee/c-725bee_service-manual_703249029.webp)
CHECK THE HANDSET ITSELF
CHECK THE +12V SUPPLY CIRCUIT
CHECK THE KEY BOARD AND MCU
CHECK THE IR IN/OUT CIRCUIT
(POWER BOARD)
IS THE +12V SUPPLY NORMAL?
IS THE REMOTE CONTROL OK?
IS THE REMOTE HANDSET ITSELF
IS THE IR IN/OUT NORMAL?
NO
NORMAL?
YES
NO
YES
NO
NO
OK
YES
YES
TROUBLESHOOTING GUIDE
IS THE SPK OUT NORMAL WHEN
INPUT IS TUNER
YES
TO KEYBOARD OK?
IS THE CABLE FROM TUNER MODULE
YES
IS THE IDLE CURRENT NORMAL?
IS THE THD BAD?
NO
YES
NO
NO
NO
YES
YES
CHECK OTHER PATRS OF THE
CHECK THE TUNER MODULE
CHECK THE PREAMP MODULE
TURN THE TRANSFORMER
CHECK THE IDLE CURRENT CIRCUIT
ADJUST THE IDLE CURRENT OR
CHECK THE AMP CIRCUIT SECTION
CHECK THE AMP CIRCUIT SECTION
CHECK THE TONE DEFEAT CIRCUIT
CHECK THE VOLUME CONTROL CIRCUIT
CHECK THE MUTE CIRCUIT
IS THE S/N BAD?
YES
NO
CHECK THE CABLE
AMP SECTION
IS THE MUTE SIGNAL HIGH LEVEL?
IS THE PREAMP MODULE NORMAL?
IS THE TONE DEFEAT CIRCUIT
IS THE VOLUME CONTROL CIRCUIT
NO
NORMAL?
YES
YES
NO
NO
NO
NORMAL?
YES
YES
YES
CHECK THE AMP CIRCUIT SECTION
CHECK THE DC SERVO CIRCUIT
CHECK THE MAIN TRANSFORMER
CHECK THE PREAMP CIRCUIT SECTION
CHECK THE PROTECTION CIRCUIT
CHECK ALL POWER SUPPLIES
CHECK THE +5V SUPPLY
AND PROTECTION CIRCUIT
CHECK THE LED CONTROL CIRCUIT
IS THE POWERAMP INPUT NORMAL?
IS THE DC SERVO CIRCUIT OK?
YES
NO
NO
AND POWER BOARD
CHECK KEY CIRCUIT
(POWER BOARD)
YES
IS IT BLUE
NO
CAN PRESSING ANY KEY TO MAKE
THE UNIT WORK NORMALLY?
IS THE 3-COLOUR-LED AMBER LIGHT?
PUSH THE POWER SWITCH TO ON
YES
IS THE SPK OUT NORMAL?
YES
IS THERE SIGNAL OUTPUT?
IS THE OUTPUT DC LEVEL NORMAL?
IS THERE ''PROTECT!'' FLASH ON VFD?
SHORT WORKING
IS THE 3-COLOUR-LED RED AFTER
NO
NO
YES
NO
NO
YES
YES
NO
ARE ALL POWER SUPPLIES OK?
IS IT RED?
NO
YES
NO
NO
Содержание C 725BEE
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