Troubleshooting - Sanyo SBM-20 Service Manual

9. Troubleshooting
Wiring diagram for repair
Symptom Procedure
Inspection
Cause Countermeasure
A. No indication ap 1) Remove the power cord
Microcomputer
Normalized
pears on LD1 from the socket. Wait 10
went out of
control due to
when the power
seconds and then turn
external noise.
plug is con-
the power on again.
YES
netted to the
power outlet
2) Measure the voltage Poor connec- Repair wiring
NO
tionofCN101
between @ and @ to
check ifAC 230V is sup
Poor connec-
Repair wiring
plied to the power
tion of connec-
board.
YES
tor lead wire.
Thermal fuse Replace ther-
failure mal fuse
3) Measure voltage to
Power board Replace power
check if the power
board
board is in normal
Fuse 315mA
Replace the
condition.
blowout
fuse 315mA
@-(@ Approx. DC5V
4) Measure voltage to NO Poor connec-
Repair wiring
check if the control
tion of 6-core
board is in normal
parallel wire
condition.
@-@ approx. DC 5V
Control board
Replace control
board
3. Operation key
1) Remove the power
Microcomputer
Normalized
input is not ac-
cord from the socket.
Start
went out of
Wait 10 seconds and
control due to
cepted.
then turn the power
external noise.
on again.
YES
NO
* Control board Replace control
failure
board
22