Technics SA-310 Service Manual

SA-EX310
Fan Motor Troubleshooting
Is the air
cooling path blocked
or the fan motorjammed
by any external
obstacle ?
Are the
terminal voltage of
Q772 and Q773 normal in both
and inactive states of the
fan motor ?
(see table1.)
The power IC ( IC601 ) is defective.
The fan motor, power ICs and fan driver
are functioning normally.
YES
Is an audio signal
present at pins 7 and
10
of IC601
NO
YES
NO
Check the integrity of Q772, Q773 and the fan
motor driving circuit. (see Fig.1)
YES
Reinstall the fan on the unit.
Is the fan
motor's DC resistance
20 ~ 30Ω ?
Fan motor failure
Short circuit : DC resistance below 5Ω
Open circuit : DC resistance over 1kΩ
NO
NO
Remove the fan from the unit.
Remove the obstacle.
YES
The Model SA-EX310 employ fan motor error sensing electronics.
If the cooling fan is not operating and "OVER LOAD" is displayed on the FL display, check the fan motor and its driving circuit.
fan. off fan. on
E 14.5V 14.5V
Q772 C 0V 14.5V
B 14.5V 0V
E 0V 8.5V
Q773 C 14.5V 14.5V
B 0V 8.5V
(Table 1)
(Voltage table)
Fig.1
"OVER LOAD" is displayed on the FL display.
M
Q777
Q776
Q773
C775
0.022
2SB621AQSTA
REGULATOR
R778
R772
4.7K
MTZJ9R1CTA
D773
CP771
FAN
MOTOR
C773
0.022
R775
R771
+
+
R776
4.7 1/4W
330
Q772
R779
10K
R777
47K
R773
10K
Q778
47K
47K
C772
C771
35V4.7
50V4.7
R774
3.3M
D771 D772
1SS133
Q772,Q776
2SC1740SSTA
MOTOR DRIVE
Q777
2SA933SSTA
MOTOR DRIVE
Q778
RVTDTA114TST
MOTOR DRIVE
D774
1SS133

Technics SA-310 Specifications

General

Brand	Technics
Model	SA-310
Category	Stereo Receiver
Language	English