Troubleshooting Guide - NAD C 325BEE Service Manual

PUSH THE POWER SUPPLY
SWITCH TO ON
NO
IS THE AMBER LED AMBER
LIGHT?
YES
NO
CAN PRESSING ANY KEY MAKE
THE UNIT WORK NORMALLY?
YES
NO
IS THE SPK OUT NORMAL?
YES
NO
IS THE REMOTE CONTROL OK?
YES
NO
IS THE 12V SUPPLY NORMAL?
YES
OK

TROUBLESHOOTING GUIDE

NO
IS IT RED?
YES
YES
YES
ARE ALL POWER SUPPLIES OK?
NO
NO
IS THE ABMER LED GREEN?
YES
YES
YES
SOME KEYS IS USELESS?
NO
NO
NO
IS THE OUTPUT DC LEVEL
NORMAL?
YES
NO
IS THERE SIGNAL OUTPUT?
YES
NO
IS THE THD HIGH?
YES
NO
IS THE IDLE CURRENT NORMAL?
YES
NO
IS THE IR IN/OUT NORMAL?
YES
NO
IS THE REMOTE HANDSET ITSELF
NORMAL?
YES
NO
IS THE 18V SUPPLY NORMAL?
YES
DID THE 12V SUPPLY SHORT
GROUND?
24
CHECK THE AMBER LED CONTROL
CIRCUIT(Q72,Q73,Q74,LED717)
CHECK 12V SUPPLY
YES
NO
IS IT GREEN?
YES
IS THE STANDBY SINGAL LOW
LEVEL?
NO
YES
IS THE POWER AMP INPUT NORMAL?
NO
YES
IS THE MUTE SIGNAL OFF?
NO
NO
IS THE VOLUME CONTROL CIRCUIT
NORMAL?
YES
NO
ARE THE TWO MODULES NORMAL?
YES
YES
IS THE S/N RATE BAD?
CHECK THE 5V SUPPLY CIRCUIT
(ON POWER BOARD)
CHECK THE LED CONTROL
CIRCUIT(Q72,Q73,Q74,LED717)
AND PROTECET CIRCUIT
CHECK THE POWER SUPPLIES
CIRCUIT
CHECK THE PROTECT CIRUIT
CHECK THE STANDBY CONTROL
CIRCUIT
CHECK THE KEYS CONNECTION
CHECK MCU AND RELAY
CONTROL CIRCUIT
CHECK THE SERVO CIRCUIT
CHECK THE POWER AMP CIRCUIT
SECTION
CHECK THE MUTE CONTROL
CIRCUIT
CHECK THE VOLUME CONTROL
CIRCUIT
CHECK THE MODULES CIRCUIT
CHECK THE TONE CIRCUIT
TURN THE TRANSFORMER
ADJUST THE IDLE CURRENT OR
CHECK THE IDLE CURRENT
CIRCUIT
CHECK THE POWER AMP CIRCUIT
(IF SOME TRANSISTORS ARE
DEFEATED)
CHECK THE IR IN/OUT
CONNECTION OR CIRCUIT(PARTS)
REPLACE THE BTTERIES OR
ANOTHER REMOTE CONTROL
HANDSET
CHECK THE IR CONTROL CIRCUIT
(INCLUDE THE IR RECEIVER AND
MCU)
CHECK THE 18V SUPPLY
CHECK THE CONNECTION
AND CHECK IF THE RELATIONAL
TRANSISTORS ARE DEFEATED