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3.3
51
2K
HAM Upgrade Instructions
To
upgrade
a
128K memory unit
to a
512K memory unit, follow the
procedure below.
1.
Remove
the top
cabinet
as
described
in 3.1.
Remove four
ICs
(IC16
-
IC19) from the IC sockets
of the
PCB (Figure
3-3),
unsolder C65
82 pF
ceramic
capacitor and remove
it.
2.
Three nylon stand-offs are
packaged with
the
RAM card. Insert
them into corresponding holes
of
the
RAM card (Figure
3-4).
3.
Align
the pin
socket of the
RAM
card over CN4 through CN6, then
slowly lower
the
Board.
4.
Snap each stand-off into the
corresponding hole
on the
computer
PCB.
5.
Connect
the
computer's AC cord and
signal cables
to a
TV monitor and
run
the
following program
to
verify proper operation
of the new
memory
chips.
6.
Secure
the top and
bottom
cabinets.
L
L
*
m
2
O
\
JiC IB
[
|
iC
19
±
)
licir
J
C65
CN4
|
<=5
C 65
;
1
lor
PAi_ verftmn
[
1
J
Figure
3-3.
Main PCB
Figure
3-4.
512K RAM Card
<Test
Prograra>
10
WIDTH
40:
PALETTE
0,0:
PALETTE
7,63: CLS8
20
POKE&HFFD9,0
30
FOR A=&H0OOOO TO
5.H5FFFF
STEP 512
40 D=RND(2
55)
50
LP0KE A,D
60 B=LPEEK(A)
70
LOCATE
10,2:
80
LOCATE
10,4:
90
IF
BOD
THEN
130
100
NEXT
A
110
LOCATE
10,10:
PRINT"RAM TEST
IS
GOOD!
1
120
P0KE&HFFD8,0: END
130
LOCATE
10,6:
PRINT"ERROR!
140
POKE&HFFD8,0: END
PRIN^'ADDRESS^A
PRINT"DATA=";D
-27-
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