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9-1 Inverter Board Circuit
The diagram of inverter board circuit is shown in Appendix (PWB-0538). The inverter supplies power for the
LCD panel back light.
9-2 Power supply Board Circuit
Please refer to 2.0 power Schematic sheet in Appendix. The 12Vdc from adaptor output is fed into J800 as regulated
power for U801 (AO4403), and as inverter main power on pin 1 of CN830. U801 provides 5Vdc to main board.
9-3 Scaling controller Board Circuit
U5, the scaling IC of MRT MASCOT V2 is a highly integrated System-on-a-Chip with very powerful functions, including
integrated 8 bit triple-channel ADC/PLL, programmable On Panel timing controller, OSD engine, and PWM back
light intensity control.
The Scaling IC features an integrated timing controller (TCON) that connects directly to commercially available
row and column drivers. All TCON signals OCLK, ECK, ORGB, ERGB, OSP, ESP, OPOL, OINV, and EINV
could be programmable drive strengths and can be disabled to control Panel.
U1, the MCU, in addition to communicating and controlling scaling IC U5, also controls other functions for the keypads,
volume, and panel power.
The DDC memory chip of U4 stores DDC data and the NVRAM chip stores timings and setting data.
The NVRAM gets serial number data from the DDC chip, so the SDA and SCL ports connect together. In order to avoid
conflict on the I2C interface while the host gets DDC data from U4, electrical switching of U009 is implemented as an
isolation role controlled by scaling IC pin GPIO7.
9-4 Audio Circuit
Please refer to 7.0 Sound Amp schematic sheet, the audio Right/Left channels are fed into pin 6 /8 of sound AMP U701
(AN7522) while Audio plug is inserted on J701 jack. The sound output amplitude depends on the bias voltage
on pin 9 of U701, which is always controlled by Q702. When mute is activated, the Q703 will be forced to saturation
to block sound output. When standby is activated, the sound outputs of U701 will drive speakers via CN701 connecter.
9. Block Diagram
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