Sharp MD-M3 Service Manual page 62

MD-M3/M1
• Disc loading is not normal.
Is disc loaded when it is inserted?
No
Is the pin 4 of CN1601 set to L state?
Yes
Is change observed on the pin 23 or 24 of IC1601?
Yes
Is change observed on the pin 30 or 31 of IC1601?
Yes
Check CN1604 and CN1604
Yes
Is ejection performed when the MD taking-out button is
pressed?
Yes
Disc retracts soon after completion of disc ejection.
Yes
Check CN1601 and SW1956.
• Playback state cannot be set.
Is it impossible to set both high reflection disc and low
reflection disc to playback state?
Yes
Only the high reflection disc cannot be played back.
Yes
Is 1.02V±0.3V (high reflection disc) applied to the pin 93 of IC1401
in the TEST mode where the high reflection disc has been
inserted?
Yes
After adjustment check as stated in item "Normal playback".
Yes
Check CN1601 and SW1956.
No
Check IC1401.
No
No
Check CN1604 and IC1601.
No
No
Check as stated in item "TEST mode check".
No
Only the low reflection disc cannot be played back.
Is 3.2V±0.3V(record enabled) or 2.06V± 0.3V (record disabled)
applied to the IC1401 pin 93 after the low reflection disc has been set?
No
Yes
Check SW1951A/B, mechanism switch PWB, and CN1601.
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No
Yes
No