Power Supply Pcb - Brother FAX218 Service Manual

3.5

Power Supply PCB

The power supply uses the switching regulation system to generate DC power (+26.6V and
+8V) from a commercial AC power supply.
The +26.6V source is stabilized and fed to the motor and solenoid for feeding documents
and recording paper or activating the automatic cutter, and also fed to the CIS LED array. It
is also fed to the main PCB where the H26.6V source is generated. The H26.6V source out-
puts 26.6V only when the H26.6V ON/OFF control signal is High, for driving the recording
head.
The +8V source is not stabilized and fed to the speaker. It is also fed to the main PCB where
the 3-terminal regulator eliminates unstabilized components of the +8V source to generate
stabilized +5V source. The +5V source is fed to the logic, control panel, and sensors.
Fuse
Commercial
AC Power Line
Lightning
Link
Surge
Absorption
Filter
Circuit
Output Feedback
Oscillator
Circuit
Power Supply Circuit
III – 22
Main PCB
Rectifier
Circuit
H26.6V
Output
Circuit
26.6 V
Output
Circuit
8 V
Output
Circuit
H26.6V ON/OFF
Control Signal
H26.6V
26.6 V
8 V