Normal Playback; Audio Playback Circuit - Sharp MD-R3 Service Manual

MD-R3

• Normal playback

When it has been confirmed that EEPROM value is normal in the TEST mode
Is initialization performed normally when high reflection disc is
played back?
No
Does disc rotate normally?
Yes
Is an attempt to read repeatedly the TOC section of low reflection
disc made?
Yes
Check the position as stated in item "lead-in switch position
measurement mode" (high reflection disc adjustment).

• Audio playback circuit

When sound is not output although the playback time display advances during playback in the normal mode.
Is audio output waveform observed on the pins 24 to 26 of
IC1701?
Yes
Is audio output waveform observed on the pins 22 and 24 of
CNS1901?
Yes
Check the main PWB.
Does the playback time display advance?
Yes
Check IC1201
Is lead-in switch turned on in the TEST mode when the pickup is on
No the innermost periphery (Is the pin 6 of OC1401 on L level?)
Check SW1953, mechanism switch PWB soldering joint, and
CNP1601 pin 1 periphery.
Since the TOC section has not been recorded on the new disc,
No
replace it with recorded low reflection disc.
Check the pins 70, 71, 72 and 74 of IC1201, and the pins
12, 16, 17, and 19 of IC1701.
No
Check connection between IC1701 and CNS1901.
No
– 68 –
No
No