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26 Illumination
26.1 The background light to the keyboard or to the display
does not work
Start the phone in the test program.
Go to MMI\Display/Top indicator test.
Activate background light with "Disp./Keyb. led on " Fig. 26.1.
Check which of the LED´s that are working.
If one or more LED´s at the display are not working, go to section 26.2.
If one or more LED´s at the keyboard are not working, go to section 26.3.
If no LED´s are working, go to section 26.4.
26.2 The LED´s at the display H651-H654 and H662 are not
working
If one LED does not work, it is almost always that one that is faulty.
There is also possible that there is a damage on the board between the pads under nearby lying
diodes.
No further action should be taken for a liquid damaged telephone.
If a replacement of a diode did not help, measure the voltage over it +4.8 V
side and +2.8 V
If the voltages are correct then the diodes are faulty.
If VBATT is missing there is a foil damage, possibly caused by liquid damages.
4/00021-3/FEA 209 544/18 B
Fig. 26.1
on the other side.
DC
Trouble Shooting Guide, Advanced
VBATT on one
DC
109(121)
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