Overheat Protection - Sanyo PLV-WF10 Service Manual

Overheat Protection

The temperature monitor system protects optical components (LCD panel, Polarization film, etc.) from the
unusual overheat inside a projector. This system is composed of two protection equipment. Each system
operation as follows ;
The temperature monitor -1;
The CPU controls Air flow.
The CPU checks the temperature by using the temperature sensor-
IC5801 and the atmospheric pressure by using pressure sensor-
IC886, inside a projector. The CPU judges data from sensors and con-
trols the air flow of the cooling fans so that the temperature inside the
projector may be maintained to normal temperature.
The CPU shuts down the projector compulsorily.
The CPU checks the temperatures by using the temperature sensors
IC2561 (near the Red LCD panel) and IC5801(inhalation air). If each
part temperature reaches to abnormal temperature(IC2561 ;
47degrees / IC5801 ; 42degrees), the CPU will shut down the projec-
tor, and will blink TEMPERATURE WARNING indicator at intervals
of 0.6 seconds. The cooling fans operate until the temperature returns
to normal. When the temperature returns to normal, the indicator
stops blinking. Then trace the cause of an unusual temperature. And
repair the projector. (Refer to the item of "temperature abnormality"
of troubleshooting.)
The temperature monitor -2 ;
The temperature switches shut down the projector compulsorily.
Temperature switches (SW903/904) are arranged near the two lamps.
Temperature Switch
"SW903" Temperature "SW903" Temperature
for Lamp-2 "SW903" switch for Lamp-2. switch for Lamp-2.
It operates at 100˚C It operates at 100˚C
It operates at 90ºC.
Temperature sensors
location
PRESSURE PRESSURE
Sensor Sensor
IC886 IC886
Temperature
Temperature Temperature
Sensor
Sensor Sensor
IC2541 IC2541
IC2561
Temperature Temperature
Sensor Sensor
IC5801 IC5801
--
The temperature monitor system --
If a temperature of lamp reaches an unusual temperature, the temper-
ature switch will operate.
SW904 (Lamp-1)-----
SW903 (Lamp-2)-----
The lamp ballast units shut down, then the projector is turned off
when the temperature switches operate.
Note :
(1) If other protection equipment (The function of signal check of
"Power failure", The temperature monitor-1, etc.) are rightly operat-
ing, the lamp does not become an unusual temperature. So, the tem-
perature monitor-2 rarely operates. However, when those protection
equipment do not operate with fault, this temperature monitor-2 oper-
ates and covers the broken protection equipment. If this temperature
monitor-2 operates, it is thought fault of other protection equipment.
Trace the fault of other protection equipment and the causes of an
unusual temperature. (Refer to the item of "temperature abnormality"
of troubleshooting.)
(2) The CPU does not check the operation of temperature switches
4R
(SW903/904). Therefore, the TEMPERATURE WARNING indicator
does not blink when the temperature switch (SW903 or 904) operates
and the projector is shut down.
-5-
It operates at 85 degrees.
It operates at 90 degrees.
"SW904" Temperature "SW904" Temperature
Temperature Switch
switch for Lamp-1. switch for Lamp-1.
for Lamp-1 "SW904"
It operates at 90˚C It operates at 80˚C
It operates at 85ºC.
4R