Tandy 1400LT - Page 183

RTC, Back up
:2 6.8K
182473
t
BDATA BUS
D3
IS2473
ADDRESS BUS
v
ZD 1
ba 02BZ4.7A
R30
2.7K
4t -"-- Tr6
,425
.'2.7K
1
*
1
E C
t
Tr4 JAlO1
B z
R26
IK R27
10K
,. .+
JC501
*
4-
R28
1K
A
SENCE I
A0
A1
A2
A3
E cs
~AO DO
~Al D1
~A2 D2
.A3
D3
(15) CKOUT
C51 30p - ISIOSCIN vCc
I
11
12
13
14
tv
+5v
BDO
1 BD1
1 BD2
1 BD3
15 - N.C
backup power
(+Back)
+5v
1
(4. 14. 15) DKN
(2, 4. 14. 15)
(2. 4. 14. 15)
(4)
(4. 14)
m
En?
m
m
*
+5v
RAlO
47K*4
ABE
AI
-A2
A ~A3
A A4
1
-
back up power
(+Back)
c54
! 1ou
t5v
JAlOl
SENSE
IC36, 37
C50
,. 54
R25
* 30
RAlO
TR4 * 6
D2
* 3
ZD 1
CTL4
BATT
1
-
74HC243 IC37
I
NOTE : backup power = 3.6 - 4.4V
!
: +V = 12 - 13V
NO. 8
7-8