Nokia 5140 Manuales De Servicio
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NPL-4/5
Company confidential
Troubleshooting Instructions
Nokia Customer Care
Page 78
Copyright © 2004 Nokia Corporation. All rights reserved.
Issue 1 05/04
Keyboard faults 4
Keyboard
faults
4
Is PTT key working ?
Measure ROW4
line from S303.
Is it ~1.8v ?
Check S303, S300,
S301 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
Yes
Keyboard
faults
5