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Customer Care Europe, Middle East & Africa
SCCE Training Group
CHAPTER 11: USER INTERFACE FAULTY
Display failure
Check mechanical appearance of display assy, especially the connector cavity.
If they are bent, it causes a blank Display /missing segments. Change part if necessary (See figure 10.1).
If LCD does not work after changing display assy, check VBB 2.8 VDC at C409/413.
Voltage at C410/412 is normally 8 VDC (generated inside of LCD assy). Check capacitors for shorts or change LCD assy
if voltage is not ok.
Check if voltage at J314 is 2.8 VDC (LCDReset) – if line is short-circuited to ground LCD does not work.
Also check if voltage at both sides of R306 is 2.8 VDC.
If above mentioned values are ok but LCD does not work probably MAD or PCB faulty.
Keypad malfunction
Check if contacts for keys on display assy are clean. Make sure that PCB is not dirty.
Check the resistance of ROW and COL lines between the keys. Probably MAD is faulty.
Backlight failure
Check VB 3.6 VDC at anode of keypad/display-LED´s.
Check VBB 2.8 VDC pin 2 and VB 3.6 VDC pin 1 of N400.
Check resistance of R403 and R404.
Check signal KBlights 2.8 VDC at pin 7/15 of N400. If voltage is ok but illumination does not work, change N400.
If no voltage is measurable there maybe a disconnection between D300 and N400 or MAD is faulty.
If backlight switches on itself after assembling battery to the phone, even though the phone keeps switched off, check R406/407
for shorts to ground. This fault often occurs in connection with liquid damages.
© NMP 2002
CONFIDENTIAL
NHM—2/5/6
3410
Date 20.11.2002
Figure 10.1
Checked by:
Customer Care E&A
31 (44)
Repairhints
Version 4.0 Approved
Approved by:
SCCE Training Group
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