Sharp MD-DR470HS Service Manual page 42

MD-DR470H/MD-DR480H
• Abnormal display
Is a waveform found in pins 8 to 10 of CN451 ?
Is pin 2 (VCC) and pin 6 (GND) of CN451 normal ?
Check the pattern and soldering of SW flexible PWB and LCD
flexible PWB. If no problem is found, replace the LCD.
• Audio playback circuit
If playback time is counted but no sound is heard during continuous playback.
Is an audio waveform found in pins 1 (TP721), 2 (TP722), 3
(TP723) and 4 (TP724) of J703 ?
Is there a pulse where duty varies in pins 2 and 5 of Q751, Q752,
Q761 and Q762 ?
Is a pulse waveform found in pins 1, 4, 9 and 12 of IC751 and
pins 1, 4, 9 and 12 of IC761 ?
Are pins 2, 5, 10 and 13 of IC751 H ?
• The spindle motor does not rotate.
Does a waveform appear in pins 26 and 27 of IC201 after
ending the test mode AUTO2 ?
Is a waveform found in pins 60 to 64 of IC601 ?
If there is no defect in soldering of IC601 and insertion of the
flexible PWB, replace the spindle motor.
No
No
No
Yes
Yes
Is a waveform found in pins 29 to 31 of IC401 ?
Yes
Check between IC401 and CN451.
Check soldering of J703, the remote control and the earphones.
Yes
If the voltage of pin 6 of Q751 and Q752 and pin 3 of Q761 and Q762
Yes
is below 2 V when setting VOLUME to MAX, check the power
supply circuit of IC813 and IC821.
Check pins 68, 69, 71 and 72 of IC201 and pin 19 of IC401.
No
Check the periphery of IC201.
No
Check the periphery of IC601.
No
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Yes
Check around IC401.
No