Technics SU-G95 - FAN MOTOR TROUBLESHOOTING GUIDE

re ta gee Ta fhe OD OOO a
WFAN
MOTOR
TROUBLESHOOTING
GUIDE
The
Models
SU-G75/G95
employ
fan
motor
error
sensing
electronics.
If
the
cooling
fan
is
not
operation
and
“OVER
LOAD”
is
displayed
on
the
FL
display,
check
the fan
motor
and
its
driving
circuit.
“OVER
LOAD?’
is
displayed
on
the
FL
display.
Is the air
cooling
path
blocked
or
the
fan
motor
jammed
by
any
external
obstacle?
YES
NO
Remove
the
fan
from
the
unit.
Is
the
fan
motor's DC resistance
20~3002?
NO
YES
Reinstall
the
fan
on
the
unit.
Are the
terminal voltage of
Q772
and
Q773
normal
in
both
active
and
inactive
states
of
the
fan motor?
NO
Remove
the obstacle.
Fan
motor
failure
Short
circuit:
DC
resistance
below
50
Open
circuit:
DC
resistance
over
1kQ
Check
the
integrity
of
Q771,
Q772,
Q773
and
the
fan
motor
driving
circuit.
(see
fig.
1.)
(see table1.)
(Voltage table)
Pov
|
ov
1
[cf
-oesv
|
-otv
|
OV
«
OV
re| |
|
es
fo]
—oav_
:
| re]
|
YES
Fan”
ofe”
-
fan”
On”
sav]
718 oY
Fan" OFF” ov
fan”
Om”
-O6S¥
Q771,772,
774,775
fam
"OFF:
OY
2SAI3Z09AIRTA
Fan
On“:
-a8y
MOTOR
ORIVE
\
ay?
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RI73
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MASOB2MTA
0
6s
ow
R783 10K
Fan“
OFF”
=
O.1¥
Fae
ox”
.-0.6¥
Fan
"OFF".
-1av
Fam
OW”
-
13.20
AQ7T3
2S8621A0STA
REGULATOR
(Table
1)
Is
an
audio
signal
present at pins @ and (0
of
IC601
or
pins
©
and @ of IC602
NO
YES
The
fan
motor,
power
ICs
and
fan
driver
are
functioning
normally.
Fig.
1
The
power
IC
(IC601
or
IC602)
is
defective.
M@
BLOCK
DIAGRAM
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