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 ;
■ Temperature monitor -1.
--- To control the driving power of the cooling fans. ----
CPU checks the temperature and atmospheric pressure inside a projector. And CPU controls the
drive power of the cooling fans so the temperature inside the projector is maintained to normal
temperature.
---- To shut down the projector. ---
CPU checks temperature of LCD panel periphery and inhalation air(IC5801). If each part temper-
ature reaches to abnormal temperature, CPU will turn off a projector, and will blink TEMPERA-
TURE WARNING indicator at intervals of 0.6 seconds. Cooling fans operate until temperature
returns to normal. Indicator will stop blink, if temperature returns to normal.
■ Temperature monitor -2. --- (Temperature check of lamps) . ----
Temperature switches are arranged near each lamp. Temperature switches will operate, if tem-
perature reaches 90 - 100 degrees.
When temperature switches have operated, lamp ballast units will be shut down, then a projec-
tor will be turned off.
Note. 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 -1
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.
Has not the temperature
switch operated?
If the temperature around FET
reaches 85 degrees, a PFC
circuit will be shut down.
Has not the temperature switch
operated?
When the temperature around a
lamp driver reaches 85 degrees, unit
lamp ballast will be shut down and a
lamp monitor signal changes from L
to H.
Refer to next
page but one
CHECK !
CHECK !
CHECK Fan
❐ Cooling fans drive power control.
CPU checks the temperature and atmo-
spheric pressure inside a projector. And
CPU controls the drive power of the cool-
ing fans so the temperature inside the pro-
jector is maintained to normal temperature.
Have not the temperature switches operated?
Temperature switches are arranged near each lamp.
Temperature switches will operate, if temperature reach-
es 90 - 100 degrees.
When temperature switches have operated, lamp ballast
units will be shut down, then a projector will be turned off.
■ Note :
CPU does not check operation of temperature switches.
Therefore, when temperature switches have operated
and a projector has shut down, TEMPERATURE-WARN-
ING indicator does not blink.
❐ Projector shut down.
CPU performs temperature check
around the LCD panel using tempera-
ture sensor IC2541 (B-side of assembly
main). If this temperature reaches 47
degrees, CPU will turn off a projector,
and will blink TEMPERATURE WARN-
ING indicator at intervals of 0.6 sec-
onds.
Temperature sensors location can see it on "protections"( page-5).
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