Casio ZD-3 Service Manual page 26

Repair Item 5: No audio signal (digital) present at output terminals.
5
Does digital signal
appear at pin 53 (DOUT) of IC702
like that shown
figuer 16 ?
Yes
* Check control/MD unit.
No
* Check circuit around and soldering IC702.
* IC702 is defective.
1 2 3 4 5
1 2 3 4 5
1 2 3 4 5
1 2 3 4 5 1 2 3 4 5 1 2 3 4
1 2 3 4 5 1 2 3 4 5 1 2 3 4
1 2 3 4 5 1 2 3 4 5 1 2 3 4
1 2 3 4 5 1 2 3 4 5 1 2 3 4
Figure 16
24
1 2 3 4 1 1 1 2
1 2 3 4
1 2 3 4
1 2 3 4
3.3V
1 2 3 4
1 2 3 4
1 2 3 4
0V