Sharp MD-C2 Service Manual page 73

• Changer disc loading is nor normal.
When a disc is loaded into the disc 1 position, does the
mechanism go to the disc 1 position?
Does pin 55 on IC1401 change to L?
Does either pin 7 or pin 9 on IC1602 change ?
Check the lift motor, CW1904.
Is a disc loading ?
Does either pin 27 or pin 28 on IC1401 change ?
Does either pin 12 or pin 13 on IC1601 change ?
Check the loading motor(M1952), CN1401.
When the MD RELEASE button is pressed, is the unloading
operation enabled.
OK
• 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".
No
Yes
Yes
No
Yes
Yes
Yes
No
Yes
Check the C1940, SW1940
No
Check the IC1602, IC1401.
No
Yes
No
Check the IC1401.
No
Check IC1601.
No
Check as stated in item "TEST mode check".
No
No
Only the low reflection disc cannot be played back.
Yes
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?
Yes No
Check SW1930, MD mechanism switch PWB, and CN1920.
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MD-C2