HP Portable PLUS - Page 78

8·12 Troubleshooting
Portable PLUS Computer
Table 8·2. Diagnostic Test Results (Continued)
Test Result
Assembly·Level
Component·Level
Oscilloscope
Replacement
Replacement Routines
Messages (continued):
Number of devices on
Check connections; if
Check connections; if HP-IL
HP-IL loop = wrong
HP-IL/HP-IB interface
HP-IL/HP·IB interface
number
connected, perform
connected, perform
system configuration
system configuration
in PAM; check HP-IL
in PAM; check HP-IL
peripheral; if occurs
peripheral; if occurs
for every peripheral,
for every peripheral,
replace the
replace A2U15 (HP-IL
motherboard PCA.
controller).
Transmitted or Rcvd.
Check test connector;
Check test connector;
RS-232
Data line(s) bad
replace the
trace signals using
motherboard PCA.
scope routine.
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 transducer 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 A2U10 (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 A2U10 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).