Operating Principles LX-105O+ Service Manual

2.3 OPERATING PRINCIPLES OF THE ELECTRICAL

CIRCUITRIES

This section describes principles of electrical
circuitries.

2.3.1 Operating Principles of the Power Supply Circuit

The electrical power required by this mechanism is developed using the
TAa
Fiher
Unit (which
combines a filter and a power transformer) and the
T14NfA
board. The Ac input passes first
through the filter circuit, where line noise is removed, and is then set to the transformer, where it is
stepped down into two separate voltages: AC 26V and AC
12C.
The transformer output is sent to
the power circuits on the
TAMA
board, which converts the power to the DC voltages (see below)
required for operation.
AC IN

Table 2-2. Voltage Applications

Voltage Purpose

I
+5
VDC
Logic circuit voltage
Holding voltage for paper feed motor
Others
+24
VDC
Carriage
motor drive voltage
Paper-feed motor drive voltage
Printhead
drive voltage
I
+12
VDC
Voltage
for the optional l/F
TAa Filter Unit
I
TAMA
Board
I

o--

Step-
Full-wave
+24
VDC
+
Filter
down
26
VAC
rectifier regulator
Circuit
Trans-
and circuit
*
former
I
smoothing
12
VAC circuit
I
+24
VDC
+
——1
~1
Full-wave regulator
,1
circuit
rectifier
and
smoothing
circuit

Figure 2-10. Power Supply Circuit Block Diagram

+24
VDC
+5
VDC
+12
VDC
2-8
Rev.
A