The standby and main (run) power supplies are located on the AC In circuit board. The standby supply is on whenever the unit has 120V AC applied. A voltage multiplier is also located on the AC In CBA. This multiplier produces the high voltage that is required for the lamp power supply. The relay that routes the AC to the doubler is the relay that is heard when the unit is plugged in. Routing the +12VS voltage through the lamp door switch operates the relay. This is a safety feature that shuts off the lamp and supply when the customer accessible lamp door is opened.
The outputs of the standby supply includes +/- 21V for the Audio circuit board, +6VS, +5VS, -5VS, +12VS and +33VS to the DM2CR. A power fail (PwrFail) signal is generated by the standby supply and is routed to the DM2CR is the event that AC is lost or that supply malfunctions. The PwrFail signal is an early warning for the DM2CR to perform emergency shut-down housekeeping procedures.
The main (run) supply provides the +5VR and the +12VR that is required by the A/V In/Out circuit board. The +9VR, +12VR, +5VR and the Power Good signal are generated by the run supply. The Power Good signal informs the light engine (via the formatter CBA) that all run voltages are nominal. This signal goes low if the run supply turns off. This allows the light engine to perform pre shutdown house keeping functions. The run supply is turn on via the On/Off signal from the DM2CDR (via connector J24605-13).
AC-IN CBA
SERVICE POSITION
DM2CR MODULE
The DM2CR module has 2 RF inputs labeled ANTENNA A and B. Antenna A is input to a Tuner/IF module that contains a tuner section and dual IF section. The tuner is capable of processing both digital and analog RF signals (ATSC & NTSC) from either terrestrial or cable sources. The tuner is a single conversion, electronically aligned tuner with improved cross-modulation, UHF image rejection, and local oscillator phase noise performance over previous tuners. Performance is tailored to handle the predicted signal environment during transition to digital terrestrial television (HDTV) service, 256QAM digital cable, as well as providing “cable ready” NTSC performance as specified by the FCC. Antenna B input is the PIP tuner and is NTSC only.
The DM2CR has 2 DTV Link connectors which are a compressed digital video inputs offering an IEEE-1394 type video connection for consumer devices such as satellite receivers, cable receivers, and digital recorders that meet the specifications for DTV Link. DTV Link is better known as 1394 or FireWire for digital televisions. Audio and video information is carried on a single wire.
The DM2CR module contains a GPIP IC (U23501) and performs the following:
- NTSC processing
- ATSC decoding
- Process YPrPb
- Process S-Video
- Decode Y+C
- Adaptive combing of composite video
- Performs PIP function
- Recover Teletext, closed caption and Gemstar data
- Digitize all 1H video inputs
- Outputs digitized YprPb
DM2CR MODULE
FORMATTER MODULE
The formatter circuit board is responsible for converting the analog video from either the DM2CR and analog inputs from the A/V In/Out circuit board into aformat that is compatible with the light engine. DC power for the formatter circuit board as well as the light engine is supplied by the main (run) power supply located on the AC In CBA. These supplies include +5VR, +12VR, +3.3VR and +2.5VR. A Pwr_Good from the run supply is routed through the formatter CBA. This signal tells the light engine that supplies are at nominal value. All functions and circuits on the formatter circuit board are monitored and controlled by the system control microcomputer in the DM2CR. This is accomplished via the RUN 2 I2C clock and data bus. The same I2C bus is also routed through the formatter board to the light engine.
The 2H and 2.14H external inputs along with sync are applied to connector BV402. Next it is applied to the BEP (Back End Processor) for processing into an analog RGB signal. The NTSC and the ATSC analog video signal (2H) from the DM2CR is applied to connector BV401. The video is also applied to IV401 for conversion to RGB. The RGB output from IV401 is then applied to the Analog to Digital (A/D) converter IW601. It’s output is 8 bit digital red, green and blue video data stream. This digital video is next applied to the Lun-IC, IW701. IW701 converts the three separate digital video streams to a 48 bit 720P digital RGB signal. This 48 bit signal is then processed by the FPGA IC IW801. The output from IW801 is a 24 bit 720P signal that the DVI transmitter can use. The DVI transmitter IW901 converts the 24 bit signal to the DVI format. These outputs exit the formatter circuit board via connector BW901 and are sent to the light engine’s DVI receiver. The DVI transmitter and receiver incorporate HDCP (High Bandwidth Digital Content Protection. The HDCP encryption format covers all high bandwidth applications such as computers, DVD players and HDTV (ATSC). Whenever the connector BW901 is disconnected the DVI transmitter turns off. This is done to protects against and prevents any video pirating.
FORMATTER CBA [SERVICE POSITION]
