SD-AT100 (serv.man6). 5 - Voltage, Troubleshooting, Function IC (95-112) - Sharp Audio Service Manual (repair manual). Page 5

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Is the disc chucked at the specified location ?

Check the changer mechanism.

Check the connection between pins 3 and 7 of 
IC705 and M3.

Does the pickup move in the direction of inner 
periphery ?

No

No

No

No

Replace IC705.

Check the cable connecting to the CS3301.
(Check the CS3301 and line of pins 13 and 14 of 
IC3801.)

Check the cable connecting to the CS3301.

Repair the changer mechanism.

Yes

Yes

No

Yes

After moving in the direction of inner periphery, 
does the pickup move in the direction of outer 
periphery ?

Yes

Check the M_8 V line.

Is 8 V being applied to the pins 8 of IC3801 ?

Yes

Replace the IC3801.

Yes

The disc does not rotate.

No

Is FE signal inputted into the pin 150 of IC3701.

Check or replace IC3701.

Check the line between the IC3301 and IC3701.

When removing disc and applying load to spin 
motor (by stopping with hand, etc.), objective lends 
moves up and down? (Checking item to symptom)
Note) If load is not applied to spin, lens does not 
move and becomes NO DISC immediately.

See FLOW CHART <The [No Disc] indication.
(In case focus servo does not function.)>

Replace IC3301.

Is there input signal on the pins(50,55) and (49,54) 
of IC3301?

Is FE signal output to the pin 21 of IC3301 when 
the disc is set ?

No

No

Check the connection of optical pickup cable.
If it is normal, replace the optical pickup.

Yes

No

Yes

Yes

Yes

The [No Disc] indication. (In case of focus error)

In case of CD.
For DVD, 58, 59, 63, and 64