Section 1: Introduction
D4K25 Service Manual
1-5
020-100880-01 Rev. 1 (06-2012)
1.5
Interlocks
The projector has a number of sensor and switches that detect when safety critical components of the projector
fail. Many of these are linked into an interlock circuit so that if there is a malfunction or an error condition the
projector’s Lamp Power Supply (LPS) is turned OFF or unable to be turned ON if already powered OFF.
Table 1.1 Safety Interlock
There are a number of sensors used to indicate the projector is operating under stress and may soon shutdown.
These warning sensors are not wired into the interlock circuit since they do not monitor safety critical areas of
the projector.
Table 1.2 Fan, Temperature and Pump Sensors
Name
Description
Lamp Door
The lamp door interlock prevents the lamp from being ignited when the lamp
door is open.
Lamp Exhaust
This sensor is mounted inside the exhaust duct to monitor the airflow velocity.
If airflow is not detected, the lamp will not ignite or remain ON.
Lamp Blower
This sensor is located at the blower inlet to monitor airflow velocity from the
blower before the air reaches the lamp or reflector. If airflow is not detected,
the lamp will not ignite or remain ON.
Name
Description
Cooling Fans
The tachometer of each fan is monitored by the Environmental Board (EVB) to
ensure it is turning at a minimum RPM. If any of the fans slow below a preset
threshold the TPC will report a warning.
Temperature Sensors
Temperatures of each DMD, integrator, prism, filtered air intake, cardcage
exhaust and lamp exhaust are tracked to ensure the projector is functioning nor-
mally. Only a severe over-temperature reading on the DMDs will result in an
automatic shutdown.
Pump
If the pump speed falls below a preset threshold the TPC will report a warning.
