No sound
Whether
each operational
amplifier IC4558 power
supply of decode
board is
normal
Whether
U207 IC4360 5V,
3.3V power supply
is normal
Whether
U207 has reset
signal
Check each voltage
stabilizing circuit
Change X203 flat cable
Check U207 power supply
circuit
Check U207 reset circuit
3. Troubleshooting process for “No sound” is shown in the figure 3.3.2.3:
Whether
power board
9V,
5V, 3.3V power supply
is normal
Change U207 IC4360
Y
N
Y
N
Y
N
Y
N
Figure 3.3.2.3 Troubleshooting flow chart for “No sound”
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