Casio MA-100 Service Manual page 7

Touch pin 5 of LSI MSM6387-13 with test
rod (+) of multimeter in resistance range,
connecting test rod (-) to ground.
Is a noise made?
No
Touch pin 6 of IC AN8053N with test rod (+)
of multimeter in resistance range,
connecting test rod (-) to ground.
Is the noise made?
No
Using a multimeter, check conductivity of
speaker at terminals on the main PCB.
Is it OK?
No
Replace speaker.
A
Measure voltage at pins 22 ~ 30 of LSI
MSM6387-13.
Yes
Is the voltage +0.3 V?
Yes
Replace LSI
MSM6387-13.
Yes
Check filter circuit around
Q101.
Yes
Replace IC
AN8053N.
— 7 —
No
Replace LSI
MSM6387-13.
Does the keyboard work?
No
Replace ceramic
oscillator X101.
Does the keyboard work?
No
Replace transistor Q102.
Does the keyboard work?
No
Check the circuit around
Q102 and X101.
Yes
Yes
Yes
End