Sanyo PLC-XF45, Service Manual, Page: 38 / 147

ASS'Y POWER
Hot circuit
AC-INPUT
CPU IC801
and
I / O
EXPANDER
IC1831
SUB POWER
System Control
INTERLOCK SW
FUSE
SW902
F901
DC out
WARNING
TEMP.
READY
PO
WER-ON/OFF
IIC-SCL & SD
A
AC
DC out
I / O
EXPANDER
POWER
CONTROL
SWITCH
INDICATORS
FAN
ON/OFF
FANS
FANS
PO
WER F
AILURE
CONTROL
LAMP
REPLACE
LAMP
Always
Switched
16V /9V /6.25V /-6V
-38-
===
NOTE : Temperature monitor operation
========================
The temperature monitor system is provided to prevents damage of optical components (the LCD panel
and polarization film etc.) inside a projector from overheat. Two protection systems are provided.
Each system operation as follows :
------
The temperature monitor -1:
------------------------------------------------------------------
■
To control the air-flow of the cooling fans.
The CPU checks the temperature and atmospheric pressure inside a projector. It checks a temperature
using temperature sensor-IC5801 and it checks an atmospheric pressure using pressure sensor-IC886.
CPU judges data from sensors and controls the air flow of the cooling fans so the temperature inside
the projector is maintained to normal temperature.
■ To shut down the projector urgent.
The CPU checks temperature of LCD panel periphery and inhalation air(IC5801). If each part tempera-
ture reaches to abnormal temperature, the CPU will turn off a projector, and will blink TEMPERATURE
WARNING indicator at intervals of 0.6 seconds. Cooling fans operate until temperature returns to nor-
mal. Indicator will stop blink, if temperature returns to normal. Trace the cause of the abnormalities-tem-
perature, and repair the projector.
------
The temperature monitor -2 :
------------------------------------------------------------------
■
Temperature check of lamps :
Temperature switches are arranged near the lamps. Temperature switches will operate, if temperature
reaches 85~90 degrees. When temperature switches have operated, lamp ballast units will be shut
down, then a projector will be turned off.
■ Note :
(1) Usually temperature monitor-2 will operate when other protection equipment did not operate with
trouble, so it is auxiliary protection equipment. When other protection equipment is rightly operat-
ing, this temperature monitor-2 rarely operates. If this temperature monitor-2 has operated it is
thought fault of other protection equipment.
(2) The CPU does not check operation of temperature switches. Therefore, when temperature switches
have operated and a projector has shut down, TEMPERATURE-WARNING indicator does not blink.
TEMPERATURE ABNORMALITY
Troubleshooting
NOTE : CPU OPERATION
■
CPU (IC801) performs an input check by the IIC-SDA
signal pin.
■
When it has detected abnormal condition, CPU turns off
the projector compulsorily. Cooling fans operate until
temperature returns to normal. Moreover, a projector
cannot be turned on during this period.
*
NOTE : TEMP. MONITOR LED OPERATION
■
The red LED indicates temperature monitor operation as follows:
LED off: Normal temperature.
LED flashes in 0.6 second interval: Abnormality temperature.
Doesn't the temperature warn-
ing indicator (red) blink?
The projector is turned off when
the temperature around the LCD
panel reaches 46 - 48 degrees.
And a temperature warning indi-
cator blinks.
CHECK !
CHECK !
CHECK Fan