Radio Shack TRS-80 Service Manual page 44

36
PC. J'"ta
T
T
U&I
I I
A ( / J - E - - - ~
Kl
'0'5
I
I
I
I
I
U3-4
I
k2
Al
~-~
'05
I
I
I I
I
I
ua:s
I
~3
A 2 ~
'05
I
I
I
I
U~4
I
I
A 3 ~
i<4
'D5
I
I
I
U.!1-1
I
I
A 4 ~
ks
•05
I
I
U:!>5 (
I
c;
A5-
1<
'05
I
I
I
U:!>~
I
I
A ( ; ~
f(7
'OS
I
US◄
I
I
A 7 ~
~B
74LS05 :
I
l
l
.Tl -Pl
Tr
I ~
I
I
I
I
2))
I
4>:
I
I
I
5>!
I
I
I
6::)
I
I
I
8 ~
I I
.L .i
\ ,----l'..JG/~~ JI/Pl
----------v
-----y-----
THESE l'ARTB MOUNTED
Of'I l'R0tESS0R 'BlYl°RD
1' / t- -
IB
!"I
N.O
>>--
~>
OP
r
0
t >>--
"RE.5£T SWITCH
N.C.
20
◊◊◊
◊◊◊
◊◊◊
-¢-◊~
THE ABOVE KEYS (MODE'S) ARE CONNECTED
II
12. 13 /4 1.5 '"
IN 'PA'P.ALLE'L WITH THE' SIMILAR /\£Y5 OF
TH£ KEYBOARD MATRIX.
"R 'PB : .3250..11..
74LS24(P
LJf',12,
DIA D2.A D.3A .D4A
m,A
FIGURE 5F. MODEL Ill CPU SCHEMATIC DIAGRAM - KEYBOARD SECTION