Portable
PLUS
Computer
Reference
Information
10-5
Table 10-1. Diagnostic Test Results (Continued)
Test Result
Assembly-Level
Component-Level Oscilloscope
Replacement
Replacement Routines
Messages (continued):
CTS line
bad
Check test connector;
Check test connector;
DSR line
bad
replace the
check serial interface
DTR line
bad
motherboard
PCA.
according to table 8-
RTS
line
bad
10, 'Repairing the
Serial
Interface:
Carrier Det line
bad
Beep Test Observations:
Three beeps
don't
Swap
transducer; re-
Swap
transducer or
sound
place tr'lnsducer or
check signal with
motherboard
PCA, as
scope during test; re-
indicated.
place the transducer,
A2U17
(PPU), or
A2U21.
Display Test Observations:
Display
doesn't
scroll
Motherboard PCA.
Replace
A2UI0
(LCD
LCD RAM write
properly
controller). LCD
RAM
read
Border line improper Display assembly. Display assembly.
Extra or missing pixels. Swap top case assem- Check VccDS at
LCD
RAM write
bly
(if
available) and
A2UI0
pins 10, 17, LCD RAM read
retry; replace display
and
21
; swap top case
assembly or the
assembly
and
retry;
motherboard
PCA, as
check display circuit or
indicated.
replace display assem-
bly, as indicated.
Row (or column) dark
Display assembly.
Display assembly.
or light
Blinking or inverse
Display assembly.
Display assembly.
display improper
Two
cursors improper
Motherboard PCA.
A2U10 (LCD
controller).
Quadrant
bad
Check continuity be-
Check continuity be-
LCD RAM write
tween
A2U10
and
tween A2UlO
and
LCD RAM read
display assembly;
display assembly; use
swap
the motherboard
scope to check for tog-
PCA,
then
retry; re-
gling signals
at
A2U10
place
di
splay assembly
pins
12-16
and
18-20;
or
the
motherboard
replace display assem-
PCA, as indicated.
bly or
A2U10 (LCD
controller), as
indicated .
•
Adjacent rows (or col-
Display assembly.
Display assembly.
umns) duplicated
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