Sony MCC3000MT, Service Manual

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3. Power supply voltage detection
The power supply voltage at the RE-309 board is measured by the A/D port on IC1202 on the AVP-18 board, and
it is posted to the system controller as the input voltage value.
4. Power system control
IC1202 on the AVP-18 board checks that the power switch on the unit is turned ON, and turns on the system
controller of IC700.
After that, it controls the power for each circuit block according to the system controller.
The system controller controls the respective power supply systems in the AVP-18 and DPR-340 boards according
to the operation mode of the device, via the POWER SUPPLY MICON (IC1202).
By turning off the power systems to unnecessary circuits blocks, power can be saved.
1-6-6. SDI System
AVP-18 Board
The Copro (IC1300) receives the parallel video signal from IC300 on the DPR-340 board and performs serial-parallel
conversion, and outputs the SDI signal.
And the Copro (IC1300) performs embedding audio signal and time code.
Output SDI signals are supplied to CN1300 and CN1301 through the cable driver (IC1305).
The PLL circuit is used to reduce jitter of the HD-SDI clock signal.
The Copro (IC1300) is controlled by IC300 on the DPR-340 board through 4-line serial communication.
The FPGA program is stored in the IC1600 ROM, and JTAG can be used to overwrite the data from IC700.
1-6-7. Power System
RE-309 Board
The RE-309 board is a DC/DC converter board for conversion from input 24 VDC to output 12 VDC. This board also
outputs the ALERT signal when output overvoltage protection or output overcurrent protection is activated.
• Input 24 VDC: 1 channel
• Output 12 VDC: 3 channels
• LED_ALERT (10 VDC blinking signal): 1 channel
1. Operation of input system and protection function
The protection function outputs a voltage of 12 VDC immediately when the input power voltage reaches the
activation voltage.
The normal input power voltage value for usual operation is 24 V ±10%.
The input protection function works as follows.
• Activation voltage: When the input power voltage rises to approx. 18.0 V, the relay is turned on to activate
the main converter IC.
• Breaking voltage: When the input power voltage lowers to approx. 15.7 V, the relay is turned off to stop the
main converter IC.
• Protection of reverse power connection: If input voltage polarity is reversely connected, the relay is
immediately turned off to stop the main converter IC.
• Protection of input system short-circuit: A 3.15 A fuse is provided in the 24 V power line to blow the fuse at
an input overcurrent to protect the circuit.
MCC-3000MT
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