Buzzer Driver; Fan Driver - Citizen CL-S6621 Technical Manual

(4) Buzzer driver

This circuit drives the buzzer.
To sound the buzzer, the CPU outputs a pulse waveform from pin 171 (BUZZER). The
transistor Q24 turns ON and OFF, and the buzzer sounds.
U1A
CPU
171
P77
[SA, Main PCB]

(5) Fan driver

This circuit drives the cooling fan ("SA, Fan") for ribbon motors.
When pin 130 (FANCTL_R) is set to "Low" level, Q101 turns ON and the fan is driven.
The fan is driven according to the temperature raise of the "SA Ribbon Motor F".
When the temperature detected by the thermistor bonded to the "SA Ribbon Motor F" is under
45 ° C (113 ° F), the fan is not driven.
When the temperature exceeds 45 ° C (113 ° F) during ribbon motor running, the fan starts to
turn.
If the temperature is 60 ° C (140 ° F) or more after the ribbon motor is stopped, the fan is kept
turned until the temperature falls below 60 ° C (140 ° F).
Fan does not turn.
U1A
CPU
FANCTL_R
D30
130
[SA, Main PCB]
BUZZER
(While ribbon motor is
45 ° C
(113 ° F)
+5V
J102
J19
2
2
+5V
12
12
FANCTL
18-20
18-20
[SA, Ribbon PCB]
+24V
BZ1
R111
Q24
DTC114EM
Fan turns.
running.)
R107
Q101
2SK3664
2-35
Operation of Control Parts
Fan turns.
- While ribbon motor is
60 ° C
running.
(140 ° F)
- Even if motor is not
running.
+5V
J106
1
D101
SA, Fan
2
CL-S6621