Sharp R-9570 Service Manual page 17

R-9570
POWER SOURCE CIRCUIT
240 V AC power is applied to the primary winding of trans-
former (Tl). The output voltage of the secondary winding of
transformer (Tl ) is then full-wave rectified by the diode bridge
and smoothed by the electrolytic capacitor to become DC vol-
tage Vp.
Then the voltage Vp is delivered to the constant voltage circuit.
Symbol Voltage
VC
-5v
Application
LSI (ICl), ACL circuit and
Temperature measurement
circuit.
VA -15v IC2.
VP
VI=+
VF-
-27V
Fluorescent display tube.
: Grid and anode voltage.
- 18.5V Filament of fluorescent display
-22v tube:
VF+ - VF-
voltage.
Figure T-3.
SYNCHRONIZING SIGNAL CIRCUIT
The secondary winding output voltage of the transformer (Tl)
is half wave rectified, subjected to a voltage division by R21
and R23 and treated as a power source synchronizing signal.
T/C TRANSFORMER
LSI
ICl
c
31
IRO E27
This is the basic timing for all time processing.
C20: Noise filter capacitor.
D20: Clamp diode.
20msec.
Figure T-4.
15