Chapter 2—Functional Descriptions
2–6
Model 330, 340SC, and 370SC Service Manual
All of the SPS output voltages except Arc Lamp power are indicated by a LED
display (see ). The LEDs are located on a bar-type display on the backplane at the
left side of the card cage. The individual LEDs will be lit when the corresponding
voltage is energized. The LEDs are wired to the SPS output power using only a
current limiting resistor so when the LED is lit, it is an indication that there is a
voltage present, not necessarily the correct voltage. To verify whether or not the
voltage at the output is correct, a voltmeter must be used to probe the output
connectors J500, J501, or J502.
+5V
+5V
STB
+24V
STB
+6.3V +15V -15V +24V +48V +107V -200V
Figure 2-2
Backplane Status Indicators.
A safety interlock switch is located on top of the power supply. The interlock
switch shuts off the System Power Supply whenever the cover is removed. During
normal operation with the cover installed, the switch is in the 'armed' position.
When the rear cover is removed, the switch will be released and cause power to
the projector to be interrupted. To run the unit without the cover installed,
override the interlock switch by pulling it up into the 'service' position. When the
cover is replaced, the switch will automatically be reset into the 'armed' position.
A circuit breaker is located on the right side of the System Power Supply. The
circuit breaker serves to remove all power from the projector (except for the
power at the input terminals) by switching it to the OFF position.
CAUTION!
The circuit breaker must be switched off, and the
projector must be disconnected from AC power prior to performance of any
maintenance, to ensure that all power is removed from the internal components of
the projector.
Normal operation of the System Power Supply is as follows:
When external power is applied, +5V Standby will always be energized as will the
internal SPS fans. +24V Standby power for operating the fans will be energized
whenever the lamp or electronics are turned-on and five (5) minutes after the
projector is shut down.
All other voltages are controlled by the power-up or power-down commands
issued by the operator.