Canon PC720 Service Manual - Page 112

Canon PC720 Manual

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OPERATIONS AND TIMING Code EMI" LOW 4 4 Cause • Thermistor (TH1, TH2; faulty) • Triac (faulty) • DC controller PCB (faulty) E1"211- 0 • Thermistor (TH1; faulty) • Fixing heater (H1; faulty) • Thermal fuse (FU1; melting) • Triac (faulty) • DC controller PCB (faulty) EL"3AU • Thermistor (TH1; faulty) • Fixing heater (H1; faulty) • Thermal fuse (FU1; melting) • Triac (faulty) • DC controller PCB (faulty) Criri , • Fixing heater film (displaced, torn) G.1-0-0 4 EC 4 rf • Main motor (M1; faulty) I 11 • DC controller PCB (faulty) jr•riu • Composite power supply PCB CLIIL1-I • DC controller PCB (faulty) Description • The thermistor (TH1) temperature exceeds 245°C during copying operation. • The thermistor (TH1) temperature exceeds the control temperature by 30°C after a press on the Copy Start key. • The thermistor (TH2) temperature exceeds 275°C during copying operation. • The thermistor (TH1) detects a temperature increase of 100°C or more within 1 sec. • The thermistor (TH1) detects a temperature increase of 40°C or more during standby after it has reached 100°C. • The thermistor detects a temperature increase of 40°C after it has reached 130°C. • The temperature detected by the thermistor (TH1) has exceeded 150°C during copying operation and maximum power is applied for 10 to 14 sec thereafter. • The thermistor (TH1) temperature exceeds 190°C during copying and then drops 170°C or less for 0.1 sec or more. • The output of the fixing film displacement sensor (PS5; '1') continues 100 ms or more while the main motor (M1) is operating. • The fixing film cannot be corrected for displacement when fixing film displacement correction mode is executed at power-on. • The revolution of the main motor deviates from the specification for 1 sec or more while the main motor drive signal (MMD=1) is being generated, i.e., remains MLOCK=0. • The actual output differs from the specified output for the high-voltage output of the composite power supply. 3 - 72 COPYRIGHT © 1994 CANON INC. CANON PCT20/74017501T70 ARO AUG.1994 PRINTED IN JAPAN (IMPRIME AU JAPON)

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OPERATIONS
AND
TIMING
Code
Cause
Description
E
MI"
4
LOW
4
•
Thermistor
(TH1,
TH2;
faulty)
•
Triac
(faulty)
•
DC
controller
PCB
(faulty)
•
The
thermistor
(TH1)
temperature
exceeds
245°C
during
copying
operation.
•
The
thermistor
(TH1)
temperature
exceeds
the
control
temperature
by
30°C
after
a
press
on
the
Copy
Start
key.
•
The
thermistor
(TH2)
temperature
exceeds
275°C
during
copying
operation.
•
The
thermistor
(TH1)
detects
a
temperature
increase
of
100°C
or
more
within
1
sec.
•
The
thermistor
(TH1)
detects
a
temperature
increase
of
40°C
or
more
during
standby
after
it
has
reached
100°C.
•
The
thermistor
detects
a
temperature
increase
of
40°C
after
it
has
reached
130°C.
E
"2
11
1
-
0
•
Thermistor
(TH1;
faulty)
•
Fixing
heater
(H1;
faulty)
•
Thermal
fuse
(FU1;
melting)
•
Triac
(faulty)
•
DC
controller
PCB
(faulty)
•
The
temperature
detected
by
the
thermistor
(TH1)
has
exceeded
150°C
during
copying
operation
and
maximum
power
is
applied
for
10
to
14
sec
thereafter.
E
"3
LAU
•
Thermistor
(TH1;
faulty)
•
Fixing
heater
(H1;
faulty)
•
Thermal
fuse
(FU1;
melting)
•
Triac
(faulty)
•
DC
controller
PCB
(faulty)
•
The
thermistor
(TH1)
temperature
exceeds
190°C
during
copying
and
then
drops
170°C
or
less
for
0.1
sec
or
more.
Criri
,
G.1-0-0
4
•
Fixing
heater
film
(displaced,
torn)
•
The
output
of
the
fixing
film
displacement
sensor
(PS5;
'1')
continues
100
ms
or
more
while
the
main
motor
(M1)
is
operating.
•
The
fixing
film
cannot
be
corrected
for
displacement
when
fixing
film
displacement
correction
mode
is
executed
at
power
-on.
4
rf
I
11
EC
•
Main
motor
(M
1
;
faulty)
•
DC
controller
PCB
(faulty)
•
The
revolution
of
the
main
motor
deviates
from
the
specification
for
1
sec
or
more
while
the
main
motor
drive
signal
(MMD=1)
is
being
generated,
i.e.,
remains
MLOCK=0.
jr•riu
CLIIL1
—
I
•
Composite
power
supply
PCB
•
DC
controller
PCB
(faulty)
•
The
actual
output
differs
from
the
specified
output
for
the
high
-voltage
output
of
the
composite
power
supply.
3
-
72
COPYRIGHT
©
1994
CANON
INC.
CANON
PCT20/74017501T70
ARO
AUG.1994
PRINTED
IN
JAPAN
(IMPRIME
AU
JAPON)