Ericsson T18s Trouble-Shooting Instruction page 37

Check the feed voltages VDIG (~3.2 V) on the marked side of C600 (class A) and
VRAD (~3.8 V) on the marked side of C482 (class A, Fig. 6.1).
• If any of the feed voltages are incorrect, proceed to chapter 3, "Doesn´t start"-
fault.
• If the voltages are correct, the fault probably is due to N450 or N800, but both
are class C components and must be calibrated after being replaced. The calibra-
tion can only be done at Advanced electrical repairs.
6.3 Doesn´t begin to charge.
Open the phone and check for liquid damages.
Make sure the pads of the system connector are not burned or oxidated.
There is often dirt on the system connector, clean it with isopropyl alcohol and a
brush.
Measure the resistance of F603 (see Fig. 6.2), it should be >200 kOhm.
• If it is too low, replace F603 and C667 (both are class A and in fig. 6.2).
Measure the resistance between GND (pin 10) and AGND (pin 4) (Fig. 6.1) at the
system connector (~0 Ohm).
* If it is incorrect, is there a foil damage and the board has to be discarded.
Measure the resistance between V450 pin 1 and X800 pin 3 (see Fig. 6.1), it should
be < 1 kOhm.
4/00021-2/FEA 209 544/12.B
T18s, T18sc Standard Electrical Repairs
Fig. 6.2.
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