SH888, S868, Standare Electrical Repair
4/00021-2/FEA 209 544/3.D
35
(66)
The functional scheme is shown in fig. 8.3
Fig. 8.3
Make sure there’s voltage (3.2V) at the pads of the faulty keys according to fig. 8.4
below. Note that the “No” key has 4.8V.
Fig. 8.4
If the voltage is missing at an entire row of keys, measure the voltage at the corre-
sponding pin of D600 (see fig. 8.3).
•
If the voltage is correct at D600 there’s a foil damage and the phone is to be dis-
carded.
•
If the voltage is missing there too, replace D600 (class B, fig.8.2).
If VDIG is missing at some keys of a row, for instance key 2 and 3, but at key 1
there’s voltage, there’s a foil damage and the phone is to be discarded. This can be
verified by measuring the resistance from a functional key to one that isn’t (~0
ohms). If the resistance is incorrect there’s a foil damage.