Chapter 2---System Description
/COVER_ON: Cover interlock signal. Indicates both covers are in place.
/LAMP_OK: Tells the ALPS that the lamp is installed, the temperature is within limits, and the lamp cooling blower is working.
Outputs:
+140 VDC boost voltage to the Laser Power Supply. Voltage: 18 to 25 VDC to maintain the arc lamp ON. Current: 30 to 38 amps to maintain the arc lamp ON. LAMP_OUT: Lamp output voltage, positive.
LAMP_RTN: Lamp return.
/LAMP_LIT: Signal to SCB that the lamp is lit.
Operation:
Two signals (/COVER_ON and /LAMP_OK) are required in order for the arc lamp to light. /COVER_ON from the cover interlock switches tells the Arc Lamp Power Supply that the covers are in place and the interlock switches are pressed down. /LAMP_OK informs the System Controller that the lamp is installed (a mechanical switch activates when lamp is installed). The System Controller sends the /LAMP_ENA signal to the Arc Lamp Power Supply. The /LAMP_ENA signal turns on the ALPS.
The Arc Lamp Power Supply then provides the +140 VDC boost voltage to a spark gap and high voltage transformer which steps up the voltage to approximately 32KV and ignites the Xenon Arc Lamp. After the Arc Lamp is lit, it is maintained on by the ALPS at a steady 20 volts and 37 amps. The /LAMP_LIT signal output informs the System Controller if the lamp is lit or not.
The Arc Lamp Power Supply is electrically and magnetically shielded to prevent noise or disturbances in the CRTs or other circuitry.
High Voltage Power Supply (HVPS)
The High Voltage Power Supply (HVPS) is located on top of the LVPS on the right side of projector ( as viewed from rear). This
supply provides the anode, focus, and screen voltages required for the three CRTs in the Model 200 projector.
The following functions are provided by HVPS:
•Phase locked loop circuit for synchronization to the horizontal sync
•Generation of anode voltages (25 KV) for all three CRTs (RGB)
Model 200 Service Manual |
