Troubleshooting (Amp Section) - Sharp MD-C2 Service Manual

• Although HF waveform is normal and time
indication is normal, no sound is not output.
Check the IC2 pin 48 (EFLG).
Check the IC2 pin 37 and 40.
Replace IC2.
• Although the power is turned on, the device does
not turn on.
Pin 54 on ICF01 changes from L to H.
Yes
Power relay RL900 turns on.
Yes
The 5V_SWD line is powered up. (ZD806
cathode)
Yes
Pin 41 of ICF01 changes from L to H and
stays there.
Yes
Check the supply power to the MD unit.
4.75 < DVCC < 6.75
6.0 < AVCC < 7.0
Yes
Check the peripheral circuits for ICF01 and
also the RESET circuit.
Yes
Yes
TROUBLE-SHOOTING (AMP SECTION)
No
When the POWER key is pressed, pin
23 of ICD01 will change from 5V to 0V.
Check between pin 54 on ICF01 and
No
Q900.
Check the power circuit (F802, Q807,
No
ZD806 etc)
If the voltage changes from L to H to
L, check QV00, QV01, QV02 and
QV03 on the SP_PROTECT line on
pin 41.
Check the power circuit (F803, Q809,
ZD805 etc)
Usually, the number of pulses of flawless disc is 100 pulses/sec or
No
less.
No
– 71 –
MD-C2
Check between POWER key and pin 23
on ICD01.
Yes
Check the serial communication line
between ICF01 and ICD01. Make sure
that the ON/STANDBY line is H.