REV.-A
Table
6-6
MAPLE
Board
Test
Points
and
Their
Functions
Name
Function
Remarks
GND Signal ground
VB+
Battery voltage
VB Backup voltage
Supply
for
6kB
V-RAM,
64kB
D-RAM,
7508
sub-CPU, and
A-D
converter
+5
Logic
circuit
voltage supply - VB+ supply
through
fuse F4 and
transistor
G6
VRF
A-D
converter reference voltage
Adjust
to
2.0
V.
E
6303
slave
CPU
enabling signal
MC Microcassette tape read data signal
4.9M
Clock signal halved
from
the primary frequency
of
9.8304
MHz
which
is used as the control clock
signal
for
the LCD
controller
SED1320.
--
MRG Issued
from
main
CPU
when
D-RAM
memory
is
read/written
or
refreshed.
SP
Microcassette
tape read data used as an
output
to
the speaker.
CL2 Keyboard Scanning clock signal
Adjust
the pulse cycle
to
11.5
to
12.5
ms.
6.5.3
Variable
Resistor
Adjustments
There are
four
variable resistors, three on
the
MAPLE board (see Fig.
6-13)
and
one
in
the
LCD
unit.
---VB+
---VB
Fig.
6-13
MAPLE
Board
Variable
Resistors
6-10
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