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projector temperature is monitored, and power wiii
turn off automatically if the temperature rises beyond
normai. The cooiing fan wi)) operate untii the temper-
ature returns to normat. This prevents projector compo-
nents from being damaged by excessive heat.
As the tamp generates heat and heat waves by
discharge, the temperatures of the )amp itself, as we)) as
the poiarizing g)ass, )iquid crysta) pane)s and other
optica) components wiif increase. Fan- induced cooiing
is essential.
The temperature of the iamp's luminous giass surface
must be iower than approximately 950 'C , the reflector
internal surface temperature must be iower than 350 "C
and the poiarizing glass and liquid crystal pane) surface
temperatures tower than 55 "C .
Temperatures may exceed these ranges if the fan
does not operate or if the projector is operated in poor
ventilation. !f the projector is used at ambient temper-
atures exceeding 35 °C , the above- mentioned temper-
atures wiii aiso exceed permissibie ranges, damaging
optical components such as the poiarizing gtass and
tiquid crystal panels.
in order to prevent damage resulting from excessive
heat. temperature sensors are located at the peripheries
of the polarizing glass and tiquid crystal pane! to monitor
temperatures.
The temperature sensor positioned near the iamp has
an applicable temperature range of 80" ± 5 °C with
hysteresis of 7 "C (sensor activates at 80" ± 5 ^C and
resets at 73 " ± 5 "C ). its main purpose is to protect
the tamp.
The temperature sensor positioned dose to the iiquid
crystal panets has an appticabte temperature range of
55 ° ± 2.5 "C with hysteresis of 7 'C - )t moans the
sensor activates at 55 ° ± 2.5 °C and resets at 48" ±
2.5 *C . its main purpose is to protect the iiquid crysta!
paneis.
Once AC power is input, the CPU (tC801) performs an
input chock at pin 33 regardless of the power on/off
setting, if the temperature at the tamp periphery reaches
approximatety 80 *C or the temperature at the periphery
of the iiquid crystal paneis reaches approximatefy 55 °C ,
an "L" signai is generated and sent to pin 33 of the CPU.
!f the "L" signai is continuous for 1 second, the CPU
sees it as an abnormal condition, automatically turning
off the projector and so turning off the iamp, and
continues cooiing fan operation untii the temperature
iowers.
in this protection mode, a)i set keys and remote
control keys do not respond. The CPU checks input at
pin 33 during coofing as wo)). The temperature sensor at
the periphery of the iamp wiii reset when the temper-
ature goes betow 73 °C , sending an "H" signal, h similar
fashion, the iiquid crystal panei temperature sensor wiii
reset betow 48 "C and output an "H" signal.
The CPU then judges normai temperature and cuts
cooling fan operation.
The red LED indicates temperature monitor operation
as foiiows:
shows the temperature monitor f!ow chart.
The iamp wiii require repiacement during operation at
some point. The yeiiow LED indicator wiii tight up after
1,000 hours of use and recommend repiacement.
Usage time wiii bo stored in non - voiatite memory
(iC807) by the CPU (iC801). Even when disconnected,
this information is retained.
After iamp repfacement, pressing the Reset switch at
the bottom of the projector wiii return iamp usage time to
0. The Reset switch activates oniy when power is on.
When this switch is pressed, a "RESET" indication wiii
appear onscreen. As the "RESET" indication cannot be
recognized immediately after power on, the Reset switch
can be operated oniy after the iamp has stabilized ("A
MOMENT!" goes off). Make sure to confirm "RESET."
The Reset switch shouid onfy be operated at iamp
repiacement.
For details, refer to LAMP REPLACEMENT procedure
—7
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