Sony RM-PJM15, Service Manual

Page: 42 / 150

3-14
VPL-PX32
3-9. Description of QD Board Circuit Operations
The functions of this board include buffer of RS-232C communication, reception of remote control
signals (CIRCS signal), and video input.
3-9-1. RS-232C Communication
In RS-232C communication, IC1901 is used as the buffer. Signals are connected to the computer by
CN1904, and passed through IC1901, CN1903, BB board, and then the Y board for communication with
the CPU on the Y board.
3-9-2. Reception of Remote Control Signals
Signals from the remote controller connected by cable are input from J1902.
They are then inverted by Q1904, and output from Pin 5 of CN1903 to the Y board.
If not connected by remote control cable, signals received by the NF and NR boards are input from Pin 6
of CN1903, passed through J1902, and output from Pin 5 of CN1903 to the Y board again.
3-9-3. Video Input
Video signals are input from J1901, and output from CN1901 to the BA board.
The video audio signals are output from CN1902 to the QA board.
3-10. Description of K Board Circuit Operations
This board amplifies audio signals and outputs them to the main speaker.
Signals input from Pin 1 of CN2900 are amplified by IC2900 and output to the main speaker from
CN2903.
Pin 3 of CN2900 inputs mute signals. When this line is High (about 4.5 V), no more signals are output to
the speaker.
3-11. Description of KS Board Circuit Operations
This board amplifies audio signals and outputs them to the sub speaker.
Signals input from Pins 3 and 5 of CN2951 are amplified in IC2950, passed through the H board from
CN2952, and output to the sub speakers.
Pin 7 of CN2951 inputs mute signals. When this line is High (about 4.5 V), no more signals are output to
the speaker.