Troubleshooting Flowcharts - Toshiba RAS-18YKH-E Service Manual

9-3. Troubleshooting Flowcharts

9-3-1. Power cannot be Turned on (No Operation at All)
< Preliminary checks >
(1) Is the supply voltage normal?
(2) Is the connection to the AC output OK?
(3) Are the connection of the primary side and the secondary
side of the power transformer inserted into the P.C. board?
(4) Is the FUSE (F01) blown?
Turn the power off for about 5
seconds and then turn it on again.
Does the OPERATION
lamp flash?
NO
Is 50Hz 220–240V AC
supplied to the primary side of
the power source transformer?
YES Refer to the figure below.
Is 12V AC supplied
to the secondary side
of the power transformer?
YES Refer to the figure below.
Is the voltage display on the rear
panel of the P.C. board normal?
(12V DC or 5V DC)
NO
12V DC, 5V DC power supply circuit failure
(DB01, C01, Q03, D01, Q01, Q02, lC03)
Transformer P.C. board (MCC-629)
Does operation start
YES
when you push the ON/OFF button
of the remote control?
NO
Does the transmission indicator of the
remote control flash normally, and is
the transmission really performed?
YES
Is the lead wire disconnected from
the infrared rays receive parts?
NO
Infrared rays receive parts
or P.C. board failure
NO
NO
YES
Primary side
Secondary side
CN32 CN33
Fig. 9-3-1 Power transformer connection diagram
YES
NO
YES
Refer to above "Preliminary checks".
Or there is a defect before the power transformer.
Power
transformer
is failure
Microcomputer
is failure
CN01
Main P.C. board (MCC-1293)
– 29 –
Operations
Check items
Probable
main causes
Remedies
Item by
symptoms
(Normal)
Remote
Replace
control
failure
Connect the
wire properly
Replace
Replace
transformer
Replace the
P.C. board
Replace the
P.C. board
CN12