Nokia NPE-4 Service Manual page 22

Customer Care Europe & Africa
SCCE Training Group
Keypad faulty
If one or more keys are not working, disassemble phone and check resistance = 0Ω between keys on same Colum and Row with
ohmmeter.
For example key 7 is not working:
Check Row D2 keys "1", "4", "7", "*"
keys "End", Down" 7", "8", "9"
Check Colum D5
If between two keys the resistance is approximate MΩ, change PWB because of broken connection.
If all resistance = 0Ω, remove Z300 EMI-Filter and measure the connection between keypad and red marked
solderpads from EMI-Filter. If connection is not ok, change PWB, because of broken connection.
If connection is ok, check with ohmmeter the resistance between ground and blue marked solderpads
resistance around 2MΩ
If resistance is lower than 1MΩ or higher than 10MΩ, change PWB, because the UPP D400 is faulty and not
changeable.
© NMP 2002
CONFIDENTIAL
NPE-4 6310/NPL-1 6310i
Date 15.08.2002
resistance between the one and the other keys= 0Ω
resistance between the one and the other keys = 0Ω
Checked by:
SCCE Training Group
22 (25)
Repairhints
Version 1.0 Approved
Approved by:
SCCE