K850
1203-2528 rev. 1
TROUBLESHOOTING
Display Problems
TROU
B
L
E
S
H
O
OTIN
G
No
Display Backlight
Ok
Replace
X4200
2.6 Volt DC
at
MP 4 (ST4201
VAUDIO26)
Yes
No
Yes
Yes
SL 5 Replace
N2000
SL 4 Scrap
Use Fault Trace SW
MMI
Display pattern
Activate
Tri color pattern
Go to Display
illumination
problems
SL 5 Replace
D2000
SL 4 Scrap
Claim Component
X4200
1.8 Volt DC
at
MP 5 (ST4200
VDDE18)
Display
Ok
No
Yes
No
START
Step 1:
Use TRS Fixture and connect the display
and keypad. Connect VBATT.
If the display is working properly at the
TRS Fixture then replace the display
If not then continue with Step 2.
Step 2:
Load ITP SW into the phone
Use TRS Fixture and connect the display
Connect: VBATT and DCIO/SEPI
Continue with the
Display problems TRS guide
Display problems
START
Step 1:
Use TRS Fixture and connect the display
and the keypad. Connect VBATT.
If the display is working properly at the
fixture then replace the display
If not then continue with Step 2.
Step 2:
Load ITP SW into the phone
Use TRS Fixture and connect the display
Connect: VBATT and DCIO/SEPI
Continue with the
Display illumination problems TRS guide
No
Display Backlights
Ok
SL 5 Replace
N2000
SL 4 Scrap
No
3.8 Volt DC at
MP 26 (TP4200)
Use Fault Trace SW
MMI
Misc
Activate
Display Backlight
15V Pk-Pk
Pulses at
MP 26 (TP4200) shortly
after Display Backlights
Is set
Replace
X4200 or Display
Yes
3.8 Volt DC at
MP 51 (V4201
Anode)
No
SL 5 Replace
L4201
SL 4 Scrap
No
Replace
V4201
Yes
Yes
3.8V
Pk-Pk Pulses
at MP 49 (R4215) shortly
after Display Backlights
is set
No
Replace
V4200
Yes
Yes
0 Volt DC
At MP 25 (TP4201)
When Display Backlight
is activated
Yes
SL 5 Replace
V4205 or N2000
SL 4 Scrap
No
1.8 Volt
Pulses at
MP 8 (R2206 OPTO_EN)
shortly after phone
Power On
SL 5 Replace
N2000
SL 4 Scrap
No
3.0 Volt
Pulses at
MP 3 (TP2203 VOPTO30)
shortly after phone
Power On
Yes
Replace
N2201
No
0.8 to 2.5
Volt Pulses at
MP 52 (N4200 Pin6)
shortly after phone
Power On
No
Yes
Replace
N4200
Yes
Flash the Phone with
EMMA
SUCR SW
Display illumination problems
/ Display Illumination Problems
SEMC Troubleshooting Manual
10
(101)