Casio MA-100 - Troubleshooting No Sound

No sound
Measure voltage at pin 13 of IC AN8053N.
Is the voltage +5 V ?
Measure voltage at pin 16 of IC AN8053N.
Is the voltage +6.8 V?
Follow flow chart
of No Power.
Measure voltage at pin 14 of IC AN8053N.
Is the voltage 0 V?
Clean contacts of the
power switch.
Replace IC AN8053N.
Turning power on, measure voltage
at pin 3 of LSI MSM6387-13.
Does the voltage raise
from 0 V to +5 V?
Clean contacts of the
power switch.
A
Yes No
No
NoYes
Yes
No
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