Trouble Shooting (Md Section); When Md Fails Operate; Power Turning-On Failure - Sharp MD-R3 Service Manual

MD-R3

When MD fails operate

If the objective lens of optical pickup is contaminated, MD may fail to operate. At first, clean the objective lens to check playback
operation. If MD fails persistently to operate, perform checks as follows.
If dust or foreign substance is accumulated on the pickup lens, playback is disturbed and indication of TOC (content of tracks) may
be disabled. Before adjusting check that the lens is clean. If the lens is contaminated, treat it as follows.
Turn off power supply, impregnate the lens cleaning paper with a small quantity of isopropyl alcohol, and gently wipe the lens with
it with due care so that the lens is not damaged. At this time do not touch the lens directly with your finger.
Is power turned on when the remote control or main unit
POWER button is pressed?
Is disc loading normal?
Is playback state set when the PLAY/PAUSE button is
pressed?
Is audio output normal?
Is record and playback operations normal?
OK

• Power turning-on failure.

Is normal operation performed when the main unit POWER is
pressed?
Is +5V applied to the pins 15 and 16 of CNP471?
Is pulse given to the pin 5 of CNP471?
Is +3.2V applied to the pin 62 of IC1401?
Is 8.4672 MHz pulse applied to the pin 15 of IC1401?
Is pulse output from the pin 34 of IC1401?
Check CNP471 and system PWB.

TROUBLE SHOOTING (MD SECTION)

Yes
Yes
Yes
Yes
Yes
No
Yes
Yes
Yes
Yes
Yes
Check as stated in item "POWER turning-on failure".
No
Check as stated in "Disc Loading is nor normal".
No
Check as stated in item "Playback state cannot be set".
No
Check as stated in item "Audion playback circuit".
No
Check as stated in item "Record playback operations".
No
Check the remote controller and display PWB.
Yes
Check the main PWB and CNP471.
No
Check the display PWB, main PWB and CNP471.
No
Check the periphery of IC1401.
No
Check IC1201.
No
Check IC1401.
No
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