Battery Circuit - Samsung ER-220 Service Manual

D. VE(+4V)
The VF voltage is used for providing the power to the filament
of the DIGITRON. The AC 4V is rectified by the diode rectifier 1N4003
and regulated by the capacitor 16V 470uF. The 4V output voltage heats
the filament of the DIGITRON.
E. VDI(-24V)
The VDI voltage is used for providing to the GRID and PLATE of
DIGITRON. The AC 22V is rectified by the diode rectifier 1N4003 and
then regulated by the capacitor 50V 100uF. The switching circuit composes
of a zener diode 24V and a transistor KSA733, it maintains the output
voltage at DC -24V.
4-2 BATTERY CIRCUIT
In the normal operation, VCC voltage goes to the BATTERY through D2,
R for the charge. At the power off, BATTERY voltage goes to the RAM
(HY6116) and RTC(RP5C15). This operation is able to keep saving the DATA
for a long time without the external power source.
>
1N4148
CON S/W
1N4448
HY6116
(RAM)
— _NI-CD 3/60D
T fas i GEOG
| (RTC)