REV.-A
Table
6-7
Variable
Resistors
and
Their
Functions
Loca-
Name
Function
tion
VR1
Speaker sound level adjustment
MAPLE
VR2 A-D converter reference voltage
Board
VR3
7508
sub-CPU clock signal adjustment (for keyboard scanning)
LCD
VR
LCD
view
angle adjustment
VR2 and VR3, listed in the Table
6-7
need
to
be adjusted
as
follow:
(1)
VR2
Adjust
the voltage across the
VRF
terminals
to
2.0V
with
VB+ at 5.0V.
(2) VR3
Adjust
the cycle
of
the pulse signal at point
"CL2"
or
Pin
21
of
IC
"2E"
to
200
kHz
±4%.
6.5.4
Jumper
and
DIP
Switch
Settings
When a computer board is replaced, set the jumpers
and/or
DIP
switches according
to
the
follow-
ing;
(1) Jumpers
Set the jumpers by referring
to
the old board
as
well
as
the descriptions in 2.5,
"Jumper
and
Switch
Setting"
paying attention
to
the following:
J1:
The
J1
setting varies depending on the type
of
main
CPU
(.uPD
70008).
Examine the main
CPU
chip (4A) on the
new
board before setting J 1 .
J5:
Use the same setting
as
the old board, A
or
B.
If
a different terminal is wired,
ghost
dis-
plays may appear on the
LCD
panel.
J2
and
J4:
Use the same settings
as
on the old board. The user may use
other
than the stan-
dard setting.
J3:
Always
use the standard setting; open
or
OFF.
(2)
DIP
switch
(SW4)
Set the individual switches
of
this
DIP
switch
assembly according
to
the descriptions in 2.5
"Jumper
and
Switch
Setting".
6.6
Microcassette
Tape
Drive
Adjustment
The microcassette tape drive requires
two
regular adjustments, reel torque and azimuth.
However, the test tapes have no directory area and cannot be read
by
the normal LOAD instruc-
tion, resulting in a message, "DEVICE UNAVAILABLE". Therefore the drive must be manually
operated
as
follows:
6-11
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