Specifications

RMU800A SERVICE MANUAL
－ 80 －
5. Control Circuit
Circuit in this section is comprised of CPU, reset IC, power supply controller and flash ROM.
5.1 CPU
IC120 (CPU) operates at 9.8304MHz. It controls the data transmission between receive circuit, transmit
circuit, control circuit, display circuit and peripheral circuit.
Figure 4 Control Circuit
5.2 Power Supply
Power supply of the radio is derived from the battery which supplies battery B+. D135 and D137 are
over-voltage protection Diodes. Power-on/off can be controlled by software.
Figure 5 Power Switch Circuit