26
1. CIRCUIT CHECK PROCEDURE
1. Low Voltage Transformer check
• The low voltage transformer is located on the P.C.B.
• Measuring condition: input voltage : 230V / Frequency : 50Hz
2. Voltage check
• Key check point
• Check method
K
R
A
M
E
R
T
N
I
O
P
K
C
E
H
C
O
N
1
IC 1 PIN 5
5 VDC
2
IC 1 PIN 8
3
IC 1 PIN 19 OR PIN 20
NOTE :
Each measure point must be measured with GND points
.
NOTE :
1.
Re
fer to
Circui
t
Diagram
(poin
t 4).
2.
Secondary
side
vol
tage of the low
vol
tage transformer changes
in
propor
t
ion
to f
luc
t
ua
t
ion
of
power
source
vol
tage.
3
. The
allowable
tolerance of the
secondary
vol
tage
is
wi
t
hin
±
5% of nominal voltage.
Terminal Voltage
5-6-7
LOAD
AC 25.3V
NO LOAD
AC 30.8V
NO
MEASURE POINT
WAVE FORM
REMEDY
REMARK
1
MP
1
DC 5V ±0.25
V
Replace VL1, EC
1
NO LOAD
2
MP
2
DC 15V ±2.0
V
Replace EC2, D12, D13, D10
NO LOAD
PRINTED CIRCUIT BOARD
T
T:20ms(50Hz)
5V
0V
T
T:250ns(4MHz)
5V
0V