No Operation, Power Led Off - Mitsubishi Diamond Pro 750SB Service Manual

2. NO OPERATION, POWER LED OFF

POWER SW
TURN OFF
CHECK
F101
CHECK
Q101, Q102, r121
CHECK
U101
U101 PIN6
PULSE O/P
POWER SW
TURN ON
1. DC P/S O/P VOLTAGE SET AT 17V,CURRENT SET
AT 200MA. POSITIVE CONNECT TO C111"+".
NEGATIVE CONNECT TO C107"-".
SCOPE SET AT 10V/DIV, 10US/DIV, PROBE
2.
CONNECT TO Q101-GATE AND C107"-".
CHECK
U101 PIN 7 VCC
NO
PIN 4 SAWTOOTH
PIN 8, 5V
FAILURE
R119, R120, R109, ZD101
6-3