Euro-500TX Handy
© Elcom, s. r. o.
Service manual
10
Euro-500TX Handy
© Elcom, s. r. o.
Service manual
11
2.1.4 The +5 V power source (VCC1)
This power source supplies a group of logical circuits with power. Those circuits are not powered all the
time (printing, serial port transmission, etc… in normal mode) and function from time to time as needed. In
the economy and standby mode this power supply is ineffectual.
2.1.5 Power supply for the printer performance circuits (VH)
This power source is used for the supplying of the printer’s thermal head performance circuits, the step-
-motor circuit, and the produces programming voltages for the fiscal memory.
2.1.6 Accumulator voltage to the VH voltage converter
The voltage converter is used to produce the VH voltage for the printer’s thermal head performance circuits.
The core element here is the LM2588-ADJ that converts the accumulator voltage to the fixed voltage of
23 V. The converter is switched off automatically when the EECR gets connected to the external power
source.
C7
330u/25V
VCC1
VCC
SAVEPWR
T5
RFP15P05(SFP9Z34)
R29
100k
T6
BC817
R35
100k
T7
BC817
R113
100k
NMI
Fig. 2.3 VCC1 power supply
C16
2200u/25V
VH
VIN
D2
MBRS340T3
T1
RFP15P05(SFP9Z34)
R1
100k
R2
100k
T2
BC817
T3
BC817
R3
100k
R4
100k
SAVEPWR
NMI
Fig. 2.4 VH power supply
BAT+
Ls1
47uH
Ds1
MBRS340T3
Rs1
2k7/F
Rs2
47k
Rs3
2k7/F
Cs3
1u
Cs1
330u/25V
VHSU
Rs5
10k
Rs4
1M
VIN
NMI
Cs4
100n
P
D
1
Comp
2
FB
3
G
N
D
4
S
W
5
S
yn
c
6
Vin
7
Us1
LM2588-ADJ
Cs2
100n
Ds2
LL4148
Rs6
2k2
Ds3
LL4148
Ts1
2N7002
Rs7
22k
Rs8
47k
Fig. 2.5 Accumulator voltage converter circuit