CASIO CTK500
Instrukcja Serwisowa

FIlter Block Since the sound signall from the CPU is a stepped waveform, the filter block is added to smooth the waveform.
VDD

2SC3112B 10K 10K 6.2K

C331J

C222(H)

C562(H)

From the CPU

To main volume
1K AG AG AG

Initial Reset Circuit When batteries are set or an AC adapter is connected, the reset IC provides a low pulse to the CPU. The CPU then initializes its internal circuit.
VDD Battery set

Reset IC S8053ANO IC4

CPU MSM6626-01 LSI1
RESET

Power On/Off Circuit When the power switch is turned on, a low level differential pulse is provided to terminal MI of the CPU. Upon receipt of the pulse, the CPU starts the power ON sequence and raises the APO signal to +5 V. When the switch is off, on receiving the KO11 signal at terminal KI0, the CPU drops the APO signal to ground level to shut down power.
VDD VDD

ON

Power Switch
OFF ON MI

CPU
KO18 KI0

MSM6626-01 LSI1 APO signal OFF: 0V ON: +5 V

OFF ON

KI1 KO11

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