- 77 -
Chassis Block Diagrams
Remote control
R/C signal is sent to pin 292 of IC301(Main CPU) and also sent to pin 20 of IC4801(Sub CPU).
Thermal switch
There is the thermal switch (SW902) above the lamp holder to prevent the internal abnormal temperature rising. If the
internal temperature reaches near 100°C, the switch will be opened and the lamp operation will be stopped.
Remark;
The thermal switch is not reset to normal automatically even if the internal temperature becomes normal, so in
this case you have to reset it manually.
Lamp cover switch
If the lamp cover is not fixed securely, the lamp cover switch(SW8803) will be open, and LAMP_SW signal will be shut off
automatically and the lamp operation will be stopped.
Temperature sensor
The projector provides the temperature sensors "TH901", "TH902" and "IC8841" to prevent the internal temperature rising
abnormally and to control the cooling fans. (refer to "Fan control circuit" for detail)
If the internal temperature rising abnormally over the threshold value, the IC301 shuts down after cooling.
Service port
The mini DIN-8 pin jack is used for service the projector with RS-232C. The RS-232C Rx/Tx signals are connected to pins
291and 386 of IC301 via IC3801(RS-232C RECEIVER/DRIVER). The main program and data are stored in IC801(FLASH ROM).
The program can be replaced with new one by specified software "FlashUpgrader".
Note;
The service port is factory default set "OFF".
When the service port is used, the item of the service port of the setting menu is changed to "ON".
(The service port cannot be used in the state of "OFF". )
Change to "OFF" after servicing ends.
(Power consumption when standing by increases in the state of "ON". )
●
Description of System control circuit
Switch of standby mode
Service port "Off" : Super standby mode
Service port "On" : Normal standby mode
