Canon D78-5132, Service Manual

Page: 82 / 134

Part 4: Troubleshooting
4-4
Fig. 4-1
IC301
SYSTEM
CONTROL
ON/OFF BUTTON
17-18
16
14
15
13
19
18
146 206
2
6
2-5
8
2
4
AC INPUT
FAN
LAMP BST_SW.
LAMP POWER
5V_SW.
5V_SW.
F601
FUSE
SW902
THERMAL SW.
Is fuse (F601) blown?
SW904
INTER LOCK
SW.
LAMP
READY
TEMP
WARNING
LAMP
REPLACE
Check that the
POWER FAIL signal
at pin 6 of IC1808 is
correct.
L : abnormal
Check that the 5V_SW signal
at pin 11 of K3D is correct.
H : Power ON
Check that the LAMP_BST_SW
signal at pin 12 of K3D is correct.
H : Power ON
Check that the LAMP_POW
signal at pin 2 of IC2882 is
correct.
KEY SW
LAMP_BST_SW
IC1803
FAN_DRIVE
(Abnormal: H)
(Power-On: H) (Power-On: H) (Power-On: H)
(Power-On: H)
(Abnormal: L)
IC1804
IC1851
FAN CONT1
IC1806
POWER LED
TEMP LED
READY LED
LAMP REP. LED
POWER_FAIL
POWER_FAIL
POWER_FAIL
IC1808
KEY SW.
LAMP_ERR
LAMP_SW
LAMP_ERR
IC2882 IC2883
PSDA
PSDA
INDICATOR
KEY SWITCHES
Check that the LAMP
indicator and READY
indicator are lighting.
If both of indicators
are not lighting,check
the primary side of
the power supply
circuit or S6V of
standby power supply
circuit.
IIC BUS