Overheating Protection - Sanyo PLC-XF45 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, IC2541 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 Blue polarization glass
(PTH901) 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 indi-
cator at intervals of 0.6 seconds. Cooling fans operate until
temperature returns to normal. Indicator will stop blink, if
temperature returns to normal.
Check the following possible causes and wait until stopping the TEMP WARNING indicator flashing.
Possible causes
- Air filter is clogged with dust particles. Remove dust from the air filter by following instruction in the
"Air filter care and cleaning" below.
- Ventilation slots of the projector are blocked. In such an event, reposition the projector so that ventilation
slots are not obstructed.
- Check if projector is used at higher temperature place(Normal operate is 5 to 35°C or 41 to 95°F)
PTH901
Temp. Sensor
(Blue polarization glass)
Temperature sensors
location

Overheating Protection

PRESSURE
SENSOR
IC886
Blue polarizer unit
IC5801
Temp. Sensor
(I )
nhalation air
--
The temperature monitor system --
----- The temperature monitor -2 : -----
(Temperature check of lamps. )
Temperature switches (SW 903~906) are arranged near the
four lamps. Temperature switches will operate, if temperature
reaches 100 degrees.
SW (903~906) -----
(Lamp-1~4)
When temperature switches have operated, lamp ballast units
will be shut down, then a projector will be turned off.
Note.
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.
-5-
It operates at 100 degrees.
Temp.
SENSOR
IC2541