Overheating Protection - Sanyo PLC-EF30 Service Manual

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 driving power 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.
The CPU controls the driving power of the cooling fans so the
temperature inside the projector is maintained to normal tem-
perature.
■
To shut down the projector.
The CPU checks temperature of Red-LCD panel periphery
(IC2541) and inhalation air(IC5801). If each part temperature
reaches to abnormal temperature(IC2541 ; 47degrees /
IC5801 ; 42degrees), 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 normal. Indicator will stop blink, if temperature returns to
normal.
Temp. SW903
for Lamp-2.
It operates
at 100˚C
Temperature sensors
location
❏

Overheating Protection

PRESSURE
SENSOR
IC886
TEMP.
SENSOR
IC2541
TEMP.
SENSOR
IC5801
--
The temperature monitor system --
--- The temperature monitor -2 : ---
(Temperature check of lamps. )
Temperature switches (SW 903~904) are arranged near the
two lamps. Temperature switches will operate, if temperature
reaches 90~100 degrees.
SW904 (Lamp-1)-----
SW903 (Lamp-2)-----
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-WARNING
indicator does not blink.
Y/V
-5-
It operates at 90 degrees.
It operates at 100 degrees.
Temp. SW904
for Lamp-1.
It operates
at 90˚C
Y/V