No Operation, Power Led Off - Mitsubishi DPLUS 74SB -BKA Service Manual

2. NO OPERATION, POWER LED OFF

POWER SW
TURN OFF
CHECK
F101
CHECK
Q101
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 C109"+".
NEGATIVE CONNECT TO C105"-".
SCOPE SET AT 10V/DIV, 10US/DIV, PROBE
2.
CONNECT TO Q101-GATE AND C105"-".
CHECK
U101 PIN 7 VCC
NO
PIN 4 SAWTOOTH
PIN 8, 5V
FAILURE
R114, R120, ZD106
6-3