Electrical Troubleshooting Guide; Power(Smps) Circuit - Toshiba SD-33VB Service Manual

ELECTRICAL TROUBLESHOOTING GUIDE

1. Power(SMPS) CIRCUIT

(1) No 5.3VA (SYS/Hi-Fi/TUNER)
NO 5.3VA.
YES
NO
Is the F101 normal?
YES
NO
Is the BD101
normal?
YES
NO
Is the R101
normal?
YES
NO
Is Vcc(8.5~21V) sup-
plied to IC101 Pin7?
YES
NO
Is the D112 normal?
YES
NO
Is there about 2.5V
at the IC103 Vref?
YES
Check the Main PCB
5.3VA/5.0V Line short?
Replace the F101.
(Use the same Fuse)
Replace the
BD101.
Replace the R101.
Is the D102
normal?
NO
Check or Replace
the D102.
Replace the D112.
Replace the IC103.
(2) No 12VA (TO CAP, DRUM MOTOR)
NO 12VA.
YES
Is the Vcc(13V) supplied to
(+) terminal in D115, D117?
YES
Is the Vcc(12V) supplied to
(-) terminal in D115, D117?
YES
Check or Replace
the Motor Vcc.
(3) No 5.0V (SYS/Hi-Fi/TUNER)
NO 5.0VA.
YES
Is 5.3VA put into
the Q160 Emitter?
YES
Is the Q162 Base
"H"?
YES
Is about 5V put into
the Q160 Base?
YES
Check or Replace
the Q162/Q160.
3-4
NO
Check or Replace
the D110.
NO
Replace the D115.
NO
5.3VA Line Check.
NO
Check the Power
Control.
NO
Check or Replace the Q162,
R157, R158, R159, D121.