C905
1222-9526 rev. 1
TROUBLESHOOTING
Back Side LED Problems
TROU
B
L
E
S
H
O
OTIN
G
- Tally LED Problems
SL 4 Replace
X4400
SL 5 Replace
N2000
START
Load ITP SW into the Phone
Use TRS Fixture
Connect: Flash Complete to the PBA
Connect: VBATT and DCIO/SEPI
Use Fault Trace SW and go to:
MMI
Misc
Init Screen Testing
Led and Backlight
Activate:
Back-Side LED
If the Back-Side LED is working on the TRS Fixture
then Replace Flash Complete
If not then continue with the
Back-Side LED Problems TRS guide
Disconnect:
VBATT and DCIO/SEPI
Disconnect:
Flash Complete from the PBA
Connect: VBATT and DCIO/SEPI
Restart Fault Trace SW and go to:
MMI
Misc
Init Screen Testing
Led and Backlight
Activate:
Back-Side LED
5 Volt DC at
MP 56 (TP4400) when
Back-Side LED
is Activated
No
Replace
N4400
Yes
Max
1 Ohm between
MP 74 (R4401) and
MP 72 (C4401)
SL 5 Replace
L4400
SL 4 Escalate
No
Yes
Back-Side LED Problems
5 Volt DC
at MP 56 (TP4400)
Yes
Replace
N4400
Connect: VBATT and DCIO/SEPI
Restart the Fault Trace SW and go to:
MMI
Misc
Init Screen Testing
Led and Backlight
Activate:
Tally LED
START
Load ITP SW into the Phone
Use TRS Fixture
Connect: Flash Complete to the PBA
Connect: VBATT and DCIO/SEPI
Use Fault Trace SW and go to:
MMI
Misc
Init Screen Testing
Led and Backlight
Activate:
Tally LED
If Tally LED is working on the TRS Fixture
then Replace Flash Complete
If not continue with the
Tally LED Problems TRS guide
Max 1 Ohm
between
MP 74 (R4401) and
MP 72 (C4401)
SL 5 Replace
L4400
SL 4 Escalate
No
Yes
Disconnect:
VBATT and DCIO/SEPI
1.8 Volt DC
at MP 134
(V4400_Pin 1)
No
Is
any of
MP 134 (V4400_Pin 1)
and MP 148 (V4400_Pin 3)
Short circuit to
PBA GND (Shield
Can Fence)
No
Replace
N2410
No
SL 5 Replace
V4400
SL 4 Escalate
Yes
Fault Trace SW:
Deactivate
Tally LED
Yes
2V – 2.5 Volt DC
at MP 148
(V4400_Pin 3)
No
SL 5 Replace
V4400
SL 4 Escalate
Fault Trace SW:
Activate
Tally LED
Yes
0 Volt DC
at MP 148
(V4400_Pin 3)
Replace
X4400
Yes
SL 5 Replace
V4400
SL 4 Escalate
No
Tally LED Problems
SEMC Troubleshooting Manual
16
(124)