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Nokia Customer Care
Troubleshooting Instructions
Company confidential
NPL-4/5/
Issue 2 05/05
Copyright
© 2005
Nokia Corporation. All rights reserved.
Page 77
Keyboard faults 3
Keyboard
faults
3
Is volume up key
working ?
Measure ROW0
line from S300.
Is it ~1.8v ?
Check S300, S301,
S303 and lines. If OK
change Z300.
If still fail change UPP
Check S300 and COL0
lines. If OK change
Z300.
If still fail change UPP
Measure COL0 from
S300 when key is pressed.
Is there 50us pulse ?
No
Yes
No
No
Change UPP
Yes
Measure ROW1
line from S301.
Is it ~1.8v ?
Check S300, S301,
S303 and lines. If OK
change Z300.
If still fail change UPP
Check S301 and COL4
lines. If OK change
Z300.
If still fail change UPP
Measure COL0 from
S301 when key is pressed.
Is there 50us pulse ?
Yes
No
No
Change UPP
Yes
Is volume down key
working ?
Keyboard
faults
4
Yes
No
Yes