Ericsson A2618s Troubleshooting Manual page 15

5.2 Illumination
Use the Service Test menu.
Choose LED/Illumination and check that the illumination lights.
If the LCD-illumination does not lights, go to section 5.2.1.
If the keyboard illumination does not lights, go to section 5.2.2.
If the top indicator does not lights green, go to section 5.2.3.
5.2.1 LCD illumination glows faintly or does not glow at all
Open the unit and check for liquid damage.
No action should be taken for liquid damaged units, send the unit on according to the local
company directives.
Make sure that the flex-film and the elastomer are correctly mounted and mechanically intact.
Give the board power and start it up.
If the LCD-leds are not lit, measure the voltage on X850:3, 3.7 ± 0.50 V
Fig .5.1.
If the voltage on X850:3 is 0 V, there is a foil damage, send the unit on according to the local
company directives.
If the voltage on X850: 3 is correct, measure that there is 0.75V ± 0.10 V
the illumination is activated, if not measure at R854 (1.0 kohm) 2.70V ± 0.10 V
measure at the side close to D600.
If the voltage at R854 is correct measure the resistance of R R854 (1.0 kohm).
If the resistance is incorrect, replace R854.
If the voltage at R854 is incorrect the fault probably is due to D600.
NOTE!
If everything is correct change the flex-film and the elastomer.
If the problem still remains, send the unit on according to the local company directives.
5.2.2 Keyboard illumination missing or faintly glowing
Open the unit and check for liquid damage.
No action should be taken for liquid damaged units, send the unit on according to the local
company directives.
Make sure that the flex-film and the elastomer are correctly mounted and mechanically intact.
4/00021-2/FEA 209 544/25 A
Since the LEDs only are lit for ~10sec.
You will need to activate a key before measuring.
Trouble Shooting Guide, Standard
(VBATT)
DC
on V853:1 when
DC,
,
DC
15(24)