Troubleshooting; Display; Key Entry - Radio Shack TRS-80 26-3650 Service Manual

5-2.
Trouble shooting
Note:
Numbers
in
CAUSE
column denote
order of
possibility.
A. Display
LSI's
to function
:
CPU,
RAMI
OPERATION
Turn
the
power switch on.
Push the
ALL RESET
button
on
the
back
of the
computer.
TROUBLE
Dot
display
cannot be shown.
No
display at
all
or
unusual
indication.
Some
dots
cannot be
displayed.
RUN
DEG
•
•
•
>
•
•
•
• • • .:
I"-
i::,'
CAUSE
1.
RAMI
2.
CPU
CPU
1.
CPU
2.
LCD
3.
Heat
seal
B.
Key
Entry
LSI's
to function:
CPU Key
input operation, Displaying.
RAM
1
Storing entered
numbers
or
characters.
TROUBLE
No
entry
at
al
Cursor moves, but entered
number
or character
cannot be displayed.
Only
characters
can be entered
CAUSE
t.
CPU
2.
Wiring
between
CPU
and
keyboard.
1.
RAMI
2.
CPU
3.
Wiring
between
CPU
and
RAM
1
1.
CPU
2.
Wiring
between
CPU
and keyboard.
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8