Casio ZD-1 Service Manual page 19

2. "CD CLOSE" is not displayed.
Is the waveform
at pin 43 of IC704 like that
shown in Fig. 13 ?
Is the waveform
at base of Q713 like that
shown in Fig. 14 ?
Does +5 V output
appear at pin 1 of
appear at pin 3 of
appear at emitter
* Check Q707, Q708 and Q903.
* Check circuit around Q707, Q708
and Q903.
Door close
Figure 13
2
No
Yes
No
Yes
No
IC708 ?
Yes
No
Does +9 V
IC704 ?
Yes
No
Does +9 V
of Q704 ?
Yes
5 V
Door close
Figure 14
* Check IC704.
* Check circuit around IC704.
* Check Q713.
* Check SW706.
* Check IC708.
* Check circuit around IC708.
* Check Q704 and Q706.
* Check circuit around Q704 and Q706.
5 V
17