HP Portable PLUS - Repairing the Keyboard

8·28 Troubleshooting
Portable PLUS Computer
Table 8·9. Repairing the Keyboard
Use this procedure if the system processors are operating, but the keyboard doesn't operate prop-
erly. If you make a repair at any step, check whether the keyboard seems to operate properly; if it
does, go back to the main diagnostic procedure in section 4.2.
1.
Step
1. Turn off the computer. (Press 00 in the
main
PAM screen, or else press and hold
(J[) for at least 5 seconds.)
2. Measure the voltage of each column line:
A2U16, pins 6-14, 46-48.
A2U17, pins 18 and 36.
3. Measure the voltage of each row line:
A2U16 pins 15-22.
DJIC...um
aUINOST1C
c .......
K .. 8CWOD
'NT.-.,
., .....
1000
Response
If all voltages are above 2.5 Vdc, go to step 3.
If any voltages are below 2.5 Vdc, check the
voltage with the keyboard disconnected from
the motherboard
PCA.
• If the voltages remain low, check continuity
on the motherboard
PCA; replace A2U16.
• If the voltages go above 2.5 Vdc, check and
repair the keyboard module.
If all voltages are below 1 Vdc, go to step 4.
If any voltages are above 1 Vdc, check the volt-
age with the keyboard disconnected from the
motherboard
PCA.
• If the voltages remain high, check continuity
on the motherboard
PCA; replace A2U16.
• If the voltages go below 2.5 Vdc, check and
repair the keyboard module.