— 4 —
CN8
*B, *D, *G
E412181*1
T1
TE-266-E2U
FUSE 1A
6
10
F1
C1
HE12TKYB103K
1SR35-100A X 4
D1
D2
D3
D4
C3
WITH HEATSINK
OSH-1625-MP
Q1 2SD2396(K)
25V4700uF
C8
HE60TKYB222K
R1 1K
ZD1
RD6. 8EB1
C7
10V100uF
R16
560
R17
150
HE60TKYB222K
C9
ZD5
RD3. 3EB2
VDD
R14
470K
Q7
2SC945
C23
ECQ-B1H103-KF
C28
DSTC50TKYR103K
CRH100-FH11J-1R0
1S2075K
RD24EB2
R3
D6
ZD3
1S2075K
2SD1803(T)
8
9
10V100
µ
50V4. 7uF
D5
C4
C11
C17
HE12TKYB103K
C6
HE50TKYB102K
ZD2
RD36EB1
Q2
R4
750
R6
24K
C5
HE12TKYB
103K
R5
100
1
2
7
3
4
5
ZD4
RD4. 3EB2
D7
1S2471
T2
DCS-267
VF1
VF2
VN
VDD
VDW
VP
PWD
GND
GNDP
I
G
H
D
E
A
B
C
F
6. CIRCUIT EXPLANATIONS
6-1. Power supply circuit
1. Plug the power cord into AC outlet, secondary voltage (9.65VAC) of the power transformer T1 will
be appears at "A" point.
2. Then, its AC voltage is rectified by the diode bridge and change it to DC voltage. ("B" point)
3. DC voltage appears more than 7V at the corrector of power transistor 2SD2396, and then the power
transistor is turned on.
Then VP is supplied. ("C" point)
4. When the VP voltage becomes more than 3.3V, the transistor 2SD945 is turned on and then PWD
signal becomes GND level. ("F" point)
When the PWD signal becomes GND level, CPU knows no power failure.
5. VP is supplied at the DC DC converter trans T2, the DC DC converter makes display and logic circuit
voltage.
VN ,VF1,VF2 :
Display voltage ("I", "J" point )
VDD
:
Logic circuit voltage ("H" point)
Transistor 2SD1803 is used for oscillating the primary voltage of DC DC converter trans.
