
-5-
AlladllMl'll
......._
(Hana
on
Illebaup
ball8ry
~============..L......;;;;;ui,..,..811da1Qit1Dlherib
adga.)
•
Do
not
_!he
ball8ry
1111111iN1
c:onl8CI
3. Coin screw insulation sheet attachment
. !
A
-
A"
cross section
:i:
The cushion must be attached
securely
.
After the cushion glue
is
dried, it cannotbe reattached.
This part must be attached.
NG
OK
This
sectionmust be
pasted
firmly
Cushion
Upper
cabinet
2. Battery holder cushion attachment
Battery spacer
1----
1.
Cabinet upper unit
0
Batteryspacerattachment
8.
Note
for
servicing
-
PC-:£220
>
~ -~AUlevel
~ - ----~STOP
>
level
~
~ t
Symbol
[Fig.
31
lights
up.
0"""-~..1-~-"---'-~~-'---•
Voltage detection ICoperation
[Fig. 2]
c
(
V
)
T
I
N
VoMt--
VDL
r
(Fig.
11
GND
LB
-----1
CPU
CPU
CAu---
(N-chopen)
R2
R1
Vee
r
.
.
,.I
This unit is equipped with the low battery detection circuit. Its opera-
tions are described below. (The parts location numbers are different
from the actual ones.)
As shown below, when the input voltage VIN exceeds detection volt-
age VO, the output becomes HIGH from LOW. When VIN falls below
DIN, the output becomes LOW.
The LSIC (MN1280) detects the CAU
l
evel and the STOP level
with
one
IC
.
To achieve
th
i
s, the input voltage applied to the input pin (2 pin)
is
div
i
ded with
R1
and R2, and R2is turned on/off by the CAUsignal.
As shown in Fig. 3, when the power voltage falls below the CAU level,
t
he BATT symbol lights
up
.
When it falls further below the STOP
l
evel
,
it
is
turned
off
.
To detect the CAU level, the CPU CAU pin is turned on (at low level)
and
t
he LB pin of the CPU
is
checked. (If the LBC pin is
low
,
the
symbol lights up.)
After detecting the CAU
l
evel, the CAU pin
i
s turned off (at
HIGH
.
)
(When the CAU
p
i
n
is
t
urned off, the resistor division
i
s not performed
and the potential at SIC
2
pin rises to drive the output to
HIGH
.
)
Then
the CPU LS pin
is
checked again to detect the STOP level.
Afte
r detecting the STOP level, the
ON/BAK
key and the RESET
switch do not work.
7.
Low battery detection circuit "
:
':
·
~
'.
C:
'
'2
~